®

& Tunneling & Underground Construction tucThe Official Publication of UCA of SME www.TUCmagazine.com Volume 14 N0. 2 May 2020

Arkansas Tunnel studies Autonomous tunnel boring TBMs for hydropower projects /////

Special Editorial Supplement from the publisher of

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Departments Cover Story 2 Chairman’s column In This Issue On page 20, the Arkansas State Highway and Transportation Department initiated 4 a high-level tunnel feasibility study for Underground construction news a proposed east-west arterial highway under Hot Springs National Park to bypass and lessen traffic conditions in the historic city of Hot Springs. On page 34, 55 Mike Mooney and his co-authors look to UCA of SME News lessons learned from the autonomous- vehicle framework.

60 Tunnel demand forecast Feature Articles

64 20 Classifieds Highway connection through Ouachita Mountains — Arkansas Tunnel study Eric Wang, Ray Sandiford and Michael Fugett

34 EPB shield tunnel-boring machine automation using the autonomous-vehicle framework Mike Mooney, Hongjie Yu and Rajat Gangrade

48 Tunnel-boring machines for Norwegian small hydropower projects Sindre Log, Rune Skjevdal and Tobias Anderson

tucmagazine.com

AN OFFICIAL PUBLICATION OF UCA OF SME | WWW.SMENET.ORG | VOLUME 14 NO. 2 | MAY 2020

Copyright 2020 by the Society for Mining, Metallurgy and Exploration, Inc. All rights reserved. TUNNELING & UNDERGROUND CON- STRUCTION (ISSN 0026–5187) is published quarterly by the Society for Mining, Metallurgy, and Exploration, Inc., at 12999 E. Adam Aircraft Special editorial section Circle, Englewood, CO 80112-4167. Phone 1-800-763-3132 or 303-973-9550. Fax: 303-973-3845 or e-mail: [email protected]. Website: www. from the publisher of smenet.org. POSTMASTER: Send changes of address to TUNNELING & UNDERGROUND CONSTRUCTION, 12999 E. Adam Aircraft Circle, Englewood, CO 80112-4167. Article copies and back issues available on microfilm or microfiche from Linda Hall Library in Kansas Mining Engineering City, Mo. Printed by Cummings Printing Co.

Reproduction: More than one photocopy of an item from SME may be made for internal use, provided fees are paid directly to the Copyright Clearance Center, 27 Congress St., Salem, MA 01970, USA. Phone 978-750-8400, fax 978-750-4470. Any other form of reproduction requires special permission from, and may be subject to fees by SME. SME is not responsible for any statements made or opinions expressed in its publications. ™ Member subscription rate included in dues. Tunneling & Underground Construction maY 2020 1 tuc& Chairman’s Column

Take advantage of your Editorial Staff Editor membership in these unique times Willaim Gleason [email protected] he past few months have brings an opportunity for us all to been extraordinary and there meet in Dallas and experience a Senior Editor looks to be no reasonable slightly different, but equally high- Georgene Renner T [email protected] way to get back to normal in the quality UCA of SME meeting. upcoming weeks and even months As this pandemic changes the ahead. This even assumes that what way we work and interact, I’ve Associate Editor was considered normal before the spoken to people working on their Margo Ellis COVID-19 shutdown will become decks at home in the sunshine and [email protected] normal again. others working in their basements. With no travel plans and Wherever you are reading this, I Production Graphic Artist everybody now working from home, suggest that you take a moment Ted Robertson what better time to investigate ways this spring and peruse the excellent [email protected] to support your industry and the SME bookstore. Why not purchase UCA? and read a copy of the History of Business Staff COVID-19 has wreaked havoc on Tunneling in the United States, or Media Manager meetings and events this spring, from obtain one of the other excellent Advertising the NBA and NHL playoffs, to Major guideline documents for your Gary Garvey League Baseball’s Opening Day technical library. [email protected] and the postponement of tunneling While you are browsing the industry events such as the World bookstore, I ask you to look with a Phone +1-800-763-3132 or +1-303-973-4200 Tunneling Congress and NoDig. somewhat critical eye as well. If there Fax +1-303-973-3845 You should have already received a is something you expected or wanted notification that the UCA of SME is to see but did not, consider making Internet www.smenet.org not exempt from this phenomenon me or any member of the executive with the cancellation of the North committee aware of this missing item Society for Mining, Metallurgy, American Tunneling (NAT) in our umbrella of technical guideline and Exploration, Inc. Officers conference in Nashville, TN that was documents. President scheduled for June 7-10. You could volunteer to take on Robert Schafer As you can imagine, the a leadership role and produce this logistics of making such a decision guideline yourself or simply make us are complicated and yet, given aware of the need, and we can pick it President-Elect the situation with COVID-19 at up from there and find somebody to William Edgerton the moment, it was not a difficult lead the charge. decision to make. The health and We are always seeking better Past President welfare of the industry and all ways to be more connected to the Hugh Miller attendees is everybody’s highest industry and be responsive to your priority. Given that we will miss out needs. You are the industry and Executive Director on NAT, our focus now turns to the should drive the bus when it comes David L. Kanagy Cutting Edge Conference (Dallas, to ideas that you want the UCA to TX, Nov. 9-11) as the largest event on pursue. My job is to respond and the UCA of SME calendar. direct traffic to make sure your needs Underground Construction Cutting Edge will take place are fulfilled by UCA of SME, which Association of SME in Dallas, TX and will be the usual is YOUR industry organization. I’ll Executive Committee blend of technical presentations, continue to do this — wherever we Robert Goodfellow (Chair), Mike Rispin (Vice discussion panels, extended question- happen to be working. Keep well and Chair), Michael F. Roach (Past Chair), Mike and-answer sessions with the safe and I look forward to seeing you Bruen, Leon J. Jacobs, Jack E. Brockway, authors and plenty of networking all in Dallas at Cutting Edge, if not Erika Moonin, Mike A. Mooney, Pamela S. opportunities in an exhibit hall with before. Moran, Mark Johnson, Matthew D. Preedy, Jon small tabletop-style booths. For those Klug, Edward Dowey, Tony O’Donnell, Robert who have not attended previously, Robert JF Goodfellow, A. Robinson, Michael Smithson, Richard perhaps the wreckage of this year UCA of SME Chair Redmond, Paul C. Schmall, and Michael Vitale

2 may 2020 Tunneling & Underground Construction

® tuc& Feature Article 1 Highway connection through Ouachita Mountains — Arkansas Tunnel study

he Arkansas State Highway and Transportation topography and local geologic conditions, an appropriate Department (AHTD) initiated a high-level tunnel tunnel construction strategy, including temporary and Tfeasibility study for the proposed East-West arterial permanent tunnel support, was developed. Considering highway under Hot Springs National Park as part of its the highly fractured nature of the novaculite, a sequential due-diligence comparison of an open-cut versus a tunnel excavation method (SEM) tunneling approach was option to create a bypass to lessen traffic impacts on developed. The SEM approach was cost estimated and historic Hot Springs. The new tunnel on the proposed East- scheduled for comparison with the open-cut alternative. West bypass highway would be situated approximately 2 km (1.25 miles) north of a planned intersection Existing conditions with Highway 70, as shown in Fig. 1. The tunnel study Geologic setting. The tunnel alignment passes through Fig.1 Location plan of proposed highway tunnel.

addressed feasibility, constructability and conceptual a prominent ridge of the Ouachita Mountains, which cost and schedule estimates for a new tunnel alignment consist of outcrops of the Big Fort Chert, the Arkansas through elevated ridge terrain featuring an extremely Novaculite and the Stanley Shale. Novaculite is the hard novaculite formation. Considering the existing site predominant geologic formation of the ridge, as the less resistant rock has been eroded over time. Novaculite is a dense, hard, fine-grained, siliceous metamorphic rock. Eric Wang, Ray Sandiford and Michael Fugett It is a subcategory of chert, which has transformed into novaculite after low-grade metamorphism. Eric Wang and Ray Sandiford, members UCA of SME, are principal engineer & associate vice Physical properties. Novaculite is a very hard and president and vice president and east practice lead, very dense rock that varies in color from white to gray- respectively, HNTB National Tunnel Practice. and black. Novaculite is not only difficult to core with very slow drilling rates but also yields minimal rock recovery Michael Fugett is assistant chief engineer, Arkansas due to very brittle properties. Table 1 presents generalized State Highway & Transportation Department, email engineering properties of novaculite, which are subject [email protected]. to confirmation based on a site-specific investigation

20 May 2020 Tunneling & Underground Construction

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Table 1 Generalized engineering properties of novaculite.

Grain size Hardness Fracture Porosity Compressive Toughness Specific Density strength (psi) gravity (pcf) Micro-crystalline 7 Conchoidal Very low 65,270 1.5 2.5 - 2.7 162 - 169 and laboratory testing program including rock mass Fig.2 characterization data. Folding in novaculite formation. The difficulties encountered during coring attempts should not be considered as anticipated behavior for the drilling of holes for blasting and/or rock bolting. In fact, percussion drilling can be successfully performed in brittle rock, as brittle rocks do break or spall under concentrated loading. However, increased bit wear should be anticipated due to the relative hardness of the rock. Novaculite’s microcrystalline structure makes it both very hard and very brittle. The formation has also been subjected to tectonically induced folding, which has caused extensive fracture patterns in the rock as shown in Fig. 2.

Subsurface profile and ground water conditions. Difficult drilling access due to remote site location and mountainous terrain limited the available subsurface data to a single test boring shown in Fig. 3 with the approximate tunnel horizon. Ground water was encountered in boring 692 at an approximate elevation of 250 m (817 ft). This indicates a ground-water level approximately Fig.3 3 m (10 ft) above the tunnel invert. The temperature of the ground water General subsurface profile for proposed tunnel. encountered during mining is anticipated to be comparable to the ambient air temperature of the area. The ground water may contain a higher-than- normal concentration of silica due to migration through silica-rich novaculite. Fortunately, silica is not detrimental to either typical waterproofing materials or in-place concrete. The current tunnel design concept considers a watertight (partially tanked) system (Fig. 4) allowing ground water to flow around the tunnel structure and either bypass the tunnel or drain into a subdrain system. The impact of potential localized depression of the ground-water table would be evaluated during subsequent phases of design. A hydrogeologic analysis would also assist in developing drainage design as well as consideration of an alternative, fully enclosed waterproofing concept. Tunnel design basis General configuration. Considering a 5.5 percent roadway grade, the proposed

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Fig.4 Tunnel space proofing.

two-lane vehicular highway tunnel extension will be excavation method. The cross section provided in Fig. 4 approximately 365 m (1,200 ft) long. The tunnel study is had been developed in conformance with the most suitable based on a straight horizontal alignment crossing through shapes for this type of tunnel and the specific space the Hot Springs National Park Mountain in Arkansas requirements of a two-lane highway tunnel. accommodating a vertical curve with a high point midway between the portals. The relatively short length of tunnel Rock loading. The study considered a permanent and the existing rock formation favor mining by sequential reinforced concrete tunnel lining to be constructed

Table 2 Rock loads using Terzaghi system.

Rock Condition: Very blocky, seamy and shattered Tunnel Width B 52 ft Tunnel Height H 32.5 ft C = B + H 84.5 ft Unit Weight γ 169 pcf Moisture γ 174 pcf Load type Estimated rock Estimated rock Equivalent rock height loads height, h (ft) Initial Avg 0.3C 25 ft 2.2 ksf 13 Upper 0.6C 51 ft 4.4 ksf 25 Final Lower 0.35B 18 ft 1.6 ksf 9 Avg (0.35B+1.1C)/2 56 ft 4.8 ksf 28 Upper 1.1C 93 ft 8.1 ksf 46

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Fig.5 Rock loads using rock mass quality (Q) system.

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Table 3 Material properties used in FEM analysis.

Material type Ground (Mohr — Coulomb model) Concrete liner (Elastic model) Saturated unit weight, g (pcf) 174 150 Factored unit weight, g (pcf) 244 210 Young’s modulus, E (ksf) 35,000 580,000 Poisson’s ratio, n 0.3 0.3 Cohesion, c (psf) 4,000 N/A Friction angle, f (deg) 55 N/A after initial support installed over the entire tunnel load and equivalent height of rock using these systems. length. The tunnel final lining is subject to rock loads The FEM analysis (Table 3 and Fig. 6) was based on imposed by the overburden, the surrounding ground a ground-relaxation scheme, conservatively assuming a and hydrostatic pressure from ground water. The lining 30 percent ground relaxation value, in order to evaluate will be subject to minimal hydrostatic pressure due to previously determined values as well as internal member the location of the ground water, which is only 3 m (10 forces for final lining design. ft) above the tunnel invert. The hydrostatic pressure is anticipated to decrease over time due to the tunnel’s Drained versus undrained. Reduction of external pressure relief and drainage system. forces acting on the final liner is promoted by A top heading and bench sequential excavation enveloping the waterproof liner with a geotextile scheme assuming 1.2-m (4-ft) round lengths was used material that will facilitate the draining of ground in the tunnel study. An initial rock support system water, thereby reducing hydrostatic pressure. Water consisting of spiles, lattice girders, shotcrete and rock collected at the base of the liner will flow through dowels was considered installed immediately after perforated pipes installed on each side of the tunnel the full cross section was excavated over the length to discharge at portals. The drained condition was of the round. Upon completion of the excavation considered representative of the tunnel conditions and installation of initial support, drainage and featuring variable ground-water levels reflecting the waterproofing, the final liner will be constructed. local topography, indicating limited (< 1.2-m or 10-ft) Rock loads on the completed tunnel primarily impart hydrostatic head. compressive stresses in the final liner. However, shear and bending stresses will be exerted on various Fire load. Fire effects on the final liner include: locations in the liner due to the nonuniform curvature (a) additional bending forces due to temperature of the tunnel cross section and uneven distribution gradient occurring between the hot interior face and of rock loads. The final liner design thickness and the cool exterior face of the liner, (b) local cracking reinforcement will be governed by the combination of and explosive spalling of concrete along the face these parameters of compressive, shear and moments. directly exposed to fire and (c) reduction of tensile Rock-loading estimates were performed using strength of reinforcing steel. The fire load resulting applicable methods, including empirical (Terzaghi, 1946), from combustion of a vehicle is generally assumed to Norwegian Geological Institute’s (NGI) Q-system be equivalent to the energy of 50 MW over a two-hour and, for comparison, a numerical finite-element period. Mitigation measures include: (a) incorporating method (FEM) analysis. Specifically, based on the additional bending stresses due to temperature gradient lone nearby boring log, the rock core within the tunnel into the design analysis as an extreme loading case to excavation zone of influence was reported as hard, verify integrity of the liner, (b) using polypropylene slightly weathered novaculite with a variable degree of fibers in the concrete mix to minimize explosive spalling, fracturing and included localized, more closely fractured which help to create voids in the concrete to allow and ferrous stained zones. Site-visit observation notes expansion of water vapor and limit buildup of internal and photographs confirmed the presence of moderately pressure, and (c) increasing concrete cover or installing to highly fractured rock conditions as well as steep cuts a passive fire protection system to protect reinforcement with minimal erosion. Hence, the rock-mass condition from being excessively heated (i.e., reduce the thermal was characterized as moderately blocky and seamy exposure of the steel). (MBS) to very blocky and seamy (VBS) under the Terzaghi rock classification system (Terzaghi, 1946) Construction considerations and as corresponding rock mass quality Q = 1 to 5, The tunnel study included the following construction representing poor to fair conditions, by NGI’s Q-system. considerations, which informed the development of the Table 2 and Fig. 5 summarize the vertical rock support cost estimate.

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Fig.6 FEM analysis results.

Excavation and support sequence. The predominant combined with structural shotcrete layer. Per Federal rock formation is very hard. However, mechanized Highway Administration (FHWA) recommendations, excavation methods, including roadheader and backhoe a portal canopy structure projecting approximately 15 excavator, appear feasible due to the moderately to m (50 ft) from the headwall will be constructed as fall highly fractured condition of the rock mass. Drill-and- protection. Additional fall protection over the portal blast excavation does not appear to be necessary based features a catch-fence device at the base of the slope, on existing rock mass conditions. Figure 7 shows a which would be subject to periodic maintenance and feasible excavation sequence totaling five drifts under cleaning. Specifically, the portal canopy section will the top heading and bench arrangement. The proposed be constructed of expanded metal liner covered by a initial support system for this type of rock condition nominal 10 cm (4 in.)-thick shotcrete layer externally includes spiling presupport measures and steel-fiber- applied. reinforced shotcrete (SRFS) with lattice girder and rock Lattice girder encased in nominal 20-cm (8-in.) dowels on 1.2 m (4 ft)-round length. shotcrete will line the interior side of the metal liner. Waterproofing layer will be installed between the inner Rock drillability. As described in the physical- shotcrete face and the final cast-in-place concrete properties section, the host rock possesses a Moh’s lining. Collection of tunnel drainage will be provided by relative hardness scale value of 7, corresponding to sedimentation (holding) tanks at each portal. the upper end of the hardness scale, and hence would require specialty percussion button bits for drilling holes Construction cost estimate for presupport spiling and rock-support dowels. A rough-order-of-magnitude (ROM) construction cost estimate for the 365 m (1,200 ft)-long roadway tunnel Portals. Portal development commences with pre- based on anticipated material quantities, equipment and cut construction via top-down excavation of headwall crew sizes came to $68 million, including an approximate for the launch portal. The portal construction begins 10 percent contingency over a 16-month construction using mechanized rock excavation equipment to duration. build a headwall battered at the steepest stable slope possible based on actual rock-mass orientation, which Conclusions extends to the proposed portal invert elevation. Lessons learned. The results of the tunnel feasibility Anticipated support includes pattern rock dowels study indicate that: (a) the tunnel option is constructible

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Fig.7 Feasible excavation sequence.

through the prevailing geological formation using mining impacts and (c) an economically sound tunnel solution methods that require commonly available equipment providing safe highway connection through mountainous and local workforce, (b) the tunnel option presents an terrain is possible. (References available from the environmentally favorable solution, with minimal surface authors.) n

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dvances made in self-driving vehicles and past two decades, driven by the key performance indicators automated drilling during the past decade suggest realized (e.g., production, ground deformation control) Athat tunnel-boring machine (TBM) tunneling and by technology (e.g., sensing, information, electro- is headed toward autonomous operation. Automated mechanization). Automation employed by today’s TBMs drilling, primarily adopted in blast-hole drilling for mining, includes basic subsystem functions including cutterhead involves driverless surface drill rigs that self-navigate to rotation speed control (akin to vehicle cruise control), a predetermined X-Y location and drill at a preset angle foam injection ratio control and numerous hydraulic and (typically vertical) to a target depth. Remote operators mechanical subsystems. Recently developed and emerging oversee the drill rigs and perform some of the operations autonomous functions include robotic tool changes (de Wardt et al., 2012; de Wardt et al., 2016; Rogers et al., (Camus and Moubarak, 2015), ring erection (Martin, 1990; 2019). In current practice, autonomy is limited to auto- Wu et al., 2011), annulus grouting (Shirlaw et al., 2004) and positioning of drill rigs, drill-rod handling and drilling fault steering (Shimz Corp., 2018; Schwob et al., 2019). Further, detection. The main motivation behind automated drilling remote operation of TBMs is routinely used in Japan has been worker safety and workforce shortage in remote through surface control centers. area operations. Improvements in production and drilling Like AVs, the motivation for autonomous shield accuracy have been reported (Kinik et al., 2014; Jacobs, tunneling is multifaceted and includes safety (of workers 2015; Lopes et al., 2018). To the authors’ knowledge, the and of overlying structures and their inhabitants) drilling process itself has not become intelligent in terms of and optimization for improved performance (e.g., learning how to drill more efficiently. less downtime, higher production). Cost efficiency Self-driving or autonomous vehicles (AVs) provide a is a considerable barrier to growth in underground compelling roadmap for autonomous TBM tunneling given construction. A key question is what role automation can the complexity of the technology development, the partial play in reducing cost. or subsystem adoption demonstrated, the human factor This article examines autonomous earth pressure and the likelihood that full autonomy will be realized balance (EPB) shield tunneling using the development within the next decade. There are six levels of autonomous of AVs as a motivating technology. The basic technology driving, levels 0-5 are summarized in Fig. 1. At the time of AVs is presented using a sensing–planning–action of this writing, AVs on the road perform at level three framework, with noted parallels to TBM tunneling. via a variety of autonomous functions including adaptive The development of autonomous EPB shield tunneling cruise control, anticollision self-braking, traffic-jam assist, subsystems is presented within the sensing–planning– self-parking and lane-centering assist. Fully AVs, where a action framework. Subsystems addressed include ground- driver is not required, and defined by levels four and five, conditioning optimization, deformation control, chamber are commercially used in less complex environments (e.g., pressure control, drive-performance optimization, annulus local shuttle services). However, fully AVs are predicted grouting, steering and ring assembly. The potential to occur within the next decade, and no fewer than benefits of EPB shield automation are discussed, as are 1,400 fully AV vehicles are currently in testing by more the challenges, both technical and nontechnical, including than 80 companies across 36 states in the United States liability and risk. (Etherington, 2019). The main motivation behind AV technology is safety. Autonomous-vehicle framework There are approximately 6.5 million motor-vehicle crashes A sensing (perception)–planning–action (control) and 37,000 traffic deaths in the United States annually framework is adopted to describe AVs and to translate to (Insurance Information Institute, 2019). The underlying autonomous EPB shield tunneling. premise is that AV technology is better at driving than humans are. Data show that collision avoidance Mike Mooney, Hongjie Yu and technology on current vehicles has improved safety, and predictions are that fully AVs will dramatically improve Rajat Gangrade safety. Another motivation is improved efficiency. With road congestion growing and limited funding to build Mike Mooney, Hongjie Yu and Rajat Gangrade, new transportation capacity, transportation agencies members UCA of SME, are Grewcock Chair are counting on significant improvements in traffic flow Professor of Underground Construction & resulting from AVs (Kockelman et al., 2017). Tunneling and Ph.D. students, respectively, TBM tunneling has advanced considerably over the Colorado School of Mines, email mooney@mines.

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Fig.1 Six levels of autonomous vehicles as defined by the Society of Automotive Engineers (Estl, 2018).

AV sensing. AV technology requires an incredible as temperature, precipitation, vehicle braking, traction amount of information that is both gathered from a suite control and windshield wiper use for road condition of sensors embedded in the AV and gleaned from dynamic forecasting (Galanis et al., 2018). Global positioning maps hosted on cloud servers. Sensing is the process of system (GPS) and inertial measurement units using identifying all relevant objects and conditions within gyroscopes and accelerometers characterize the position the relevant field of view that an AV requires. Sensing and trajectory of the AV (i.e., AV localization (Fig. 2)). includes identifying objects (animal, baby stroller, traffic There are some important sensing similarities and signs/signals, pedestrians, other vehicles) as well as their differences with TBM tunneling. The biggest difference speeds and trajectories (Yurtsever et al., 2019). Sensing lies in remote-sensing technologies. While AVs can use also involves internet of things (IoT)-enabled information optical, LiDAR, radar and ultrasonic to image the desired (from vehicle to vehicle and from smart signage). field (tens of meters) with the requisite spatial resolution, An array of remote sensors outfitted on the AV include tunnel-project remote-sensing options are very limited. optical red, green blue depth (RGBD) cameras, radar, Geophysical seismic, GPR and electrical resistivity ultrasound and light detecting and ranging (LiDAR) methods have been used with only marginal efficacy to (Rosique et al., 2019). Infrared sensing and ground- characterize the ground ahead of TBMs (Mooney et al., penetrating radar (GPR) are also gaining acceptance. This 2012). We posit, however, that remote sensing is much suite of remote-sensing technologies provides redundancy more important to AVs than it is to autonomous TBMs. and ideally complete coverage day or night and in all- Regarding similarities, AVs need to operate at night and weather environments (day, night, fog, rain, snow, smoke). in the most adverse weather conditions (rain, snow, fog). A critical component of sensing is identifying objects from Similar objects that are sensed can change (e.g., pedestrian remotely sensed information. A radar image, for example, layers of clothing, size of animal, other vehicle model and can convey the size, shape, speed and trajectory of an age). This introduces significant ambiguity and uncertainty. object, but it does not indicate what the object is (Fig. In shield tunneling, the ground conditions also vary 2). Machine learning, embedded within the technology spatially. of computer vision, plays a significant role in object Despite tremendous advances, AV sensing is not fully identification. capable of enabling level-five AVs. Sensing techniques AV technology also uses high-resolution maps as a struggle to identify some objects (e.g., a ball in the road quasi-baseline condition for route and motion planning. that has led to AVs stopping). Sensing will also be the Such maps include road configurations and current limiting factor in autonomous EPB shield tunneling. We information about traffic, weather-impacted road cannot reliably image the ground ahead of the TBM, and conditions, construction conditions, etc. These maps are we do not know what is happening in the critical tool gap, highly dynamic based on real-time measurements of cutterhead openings and excavation chamber. These zones vehicle speed and congestion for traffic forecasting as well of critical operation need to be better sensed.

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Fig.2 Left: Object sensing using camera-measured image (Aryal, 2018). Right: Localization of AV (courtesy of ZME Science, https:// www.zmescience.com/science/news-science/self-driving-car-how-it-sees/).

AV planning. The process of planning is the intelligent tracking, or automatic parking. MPC is a more robust brain behind AV technology. This is the process and capable controlling strategy. The central idea of undertaken to perform path planning (route optimization/ MPC is to calculate the vehicle actions at each time step selection) and motion planning (the longitudinal by minimizing a cost function (error between desired acceleration/braking and lateral steering commands) for and predicted performance) over a short time horizon, the AV. Considerable machine learning is used within the while considering observations, input-output constraints planning process. Path planning determines the route from and the system’s dynamics given by a process model. the starting position to a desired destination. To find the The cost function may consider multiple performance optimal path from all potential routes, traditionally graph- goals including static safety (collision avoidance of fixed based methods are used, which consider the optimization objects), dynamic safety (avoiding other moving traffic of some objective value over all paths (e.g., minimal objects), energy efficiency, ride smoothness, etc. The input distance). Also, model predictive control can be used to constraints may include the range limit of steering, brake/ plan for a limited path ahead. Deep learning methods acceleration, etc., while the output constraints consist of have been recently used for path planning as well. One vehicle speed limit, vehicle cross-track error (deviation) representative method is imitation learning, which uses limit, orientation limit and lateral acceleration limit. the recorded driving experience to learn how human AV-motion planning is very relevant and transferrable drivers pick driving paths from the camera-observed to TBM automation. In TBM automation, the objective images. In that case, the model input is convolutional (cost) function also consists of multiple goals (higher neural network (CNN)-processed camera images and advance rate, minimal ground disturbance and the output is the human-chosen trajectory. Considering deformation, minimal tool wear, minimal alignment TBM automation, route planning is literally not relevant deviations). Furthermore, the inputs and outputs, like AVs, because the design tunnel alignment is prescribed. are subject to various limitations (thrust force limitation, However, the process of route planning can be applied to deviation limitation, torque limitation, chamber pressure other TBM subsystems. limitation, etc.). The TBM dynamics can be modeled based Motion planning to generate the longitudinal on physics to some extent, but this is uncertain. The ground acceleration/braking and lateral steering commands condition is uncertain due to geotechnical variability, for the AV uses physics-based kinematic and dynamics similar to the uncertain traffic environment caused by models to determine the action required for the given random driver/pedestrian behavior. scenario. In complex cases, machine-learning methods are used to learn the system dynamics, where the AV action. AV action is concerned with executing the past vehicle states are model inputs and the vehicle planned operational parameters from the planning stage. observations are the outputs. Either physics-based or The most common feedback controller used in AVs is the machine-learning-based models can be used within proportional-integral-derivative (PID) controller. This strategies such as iterative learning control (ILC) and seems to also be the case for TBMs. The technology to model predictive control (MPC). ILC is simple and implement the action phase is straightforward and already computationally lightweight, and is suitable for controlling developed. As such, little further discussion on action is systems that work in a repetitive mode, such as path included in this paper.

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Fig.3 Subsystem autonomous operations for EPB shield TBM (image portion courtesy of Herrenknecht).

Autonomous EPB shield tunneling autonomous framework. The development of autonomy in subsystem functions has been the mode of operation in AVs and drilling. The Ground-conditioning optimization. Ground same is likely true for EPB shield tunneling. This section conditioning (Fig. 4) is applied to help transform the in summarizes the various subsystem functions in EPB situ ground (soil, rock) into a workable medium possessing shield tunneling and how they have or will become more a consistency that can be used to smoothly balance the autonomous. Seven subsystem autonomous functions water and earth pressure at the face, dissipate that pressure are illustrated in Fig. 3. None of these subsystems are through the screw conveyor, minimize wear and energy mutually exclusive; they are all interrelated. As such, required to process, and make for efficient muck passage the optimization of parameters within a subsystem is through the cutterhead, excavation chamber, screw and constrained and a system optimization framework is disposal system (conveyor belt, buckets, truck transport, required. Of the subsystems illustrated in Fig. 3, annulus etc.). There are considerable nuances within this broader grouting, steering and ring erection have become semi- or goal that depend on ground type. For example, clays fully automated and will not be described due to page and shale present a clogging risk that conditioning must limitations. The development of ground conditioning mitigate. Cohesionless sands present ground-water inflow optimization and drive-performance optimization risk and abrasivity that conditioning should mitigate. subsystems are detailed using the sensing–planning–action To this end, there is a suite of ideal conditioned soil Fig.4 Foam generation and delivery system on a metro-size EPBM.

40 may 2020 Tunneling & Underground Construction PSC_TUC Ad_May 2020_v1_041720.indd 1 4/17/20 1:02 PM ® tuc&

parameters that can be defined depending on the ground outcomes are likely different. To this end, the model type. These include slump, permeability, shear strength, must be calibrated on the fly. Machine-learning compressibility and viscosity for cohesionless sands, and models, by design, learn while doing and therefore will consistency index, viscosity and adhesion for cohesive continuously expand knowledge of conditioning as data clays. However, there are numerous optimal conditioning are collected. Where there are co-dependent relationships inputs that vary ambiguously across soil types, including that sometimes may conflict, a weighting system is the type of conditioning agent, liquid quantity, foam implemented. Examples of this include a desire to reduce injection ratio, foam expansion ratio and concentration. cutterhead torque to some set point and a desire to In addition, the configuration and size of the cutterhead, maintain a set-point chamber pressure gradient. These excavation chamber and screw conveyor play a significant two outcomes may invoke different conditioning actions. role in the conditioned muck properties. Action. The recommended adjustments are Sensing. Ideally, we wish to know the properties of implemented via the EPB shield’s PLC that sends the conditioned state in the tool gap, cutterhead windows, analog signals to the system actuators to adjust flow excavation chamber and screw conveyor. These properties rates as prescribed (e.g., flow controllers in Fig. 4). The include shear strength, compressibility and adhesion. array of actions include different recommendations for In current EPBM tunneling, these properties are not cutterhead, excavation chamber and screw conveyor directly measured in the desired locations. Instead, we conditioning. A feedback control loop is used to rely on indirect measurements, including cutterhead implement the continuous loop of sensing, planning thrust force and torque, chamber pressure fluctuation and and action. The loop is typically completed on a time gradient from crown to invert, screw conveyor torque interval of 5-10 minutes for soil conditioning given the and pressure gradient and measured properties from belt latent response to action. Autonomous soil-conditioning samples (stickiness, slump, density, shear strength). Sensing optimization (McLane, 2014) can also incorporate within future EPBM may involve multiphysics belt muck geotechnical information (e.g., both from the ground scanning, direct sensors (e.g., rheometer, embedded in the model built from geotechnical site investigation data and tool gap, chamber and screw conveyor). from EPBM prediction of the ground type using deep learning). Planning. Measurable criteria are needed, including: Drive-performance optimization. Tunneling • Chamber pressure fluctuation (dp/dx where p = performance is determined by multiple factors, such pressure and x = longitudinal/advance position), as machine advance rate, alignment deviations, ground chamber pressure gradient (dp/dz where z is the settlement/disturbance, material consumption and tool vertical position), and screw pressure gradient (dp/ wear. Depending on the specific scenario, their priorities dL where L is length along screw conveyor). vary. For example, when tunneling in a deformation • Belt muck properties (density, adhesion, shear sensitive area, achieving minimal alignment deviation and strength under a desired pressure, slump). ground disturbance is critical. Conversely, a project that • Cutterhead torque, cutterhead thrust force. has experienced significant delays may prioritize high advance rate. When the performance metric is specified, The relationships between desired outcomes and optimizing drive performance is an optimal control measured outcomes must be developed as a function problem, in which the machine operations are adjusted of conditioning variables (e.g., form of conditioning, to achieve the best expected performance. To this end, location of conditioning, foam injection ratio (FIR), foam models relating operations with performance (Mokhtari, expansion ratio (FER), water injection ratio, bentonite et al., 2020) are needed, either derived from physics or injection ratio). Such relationships can be developed from via statistical learning. In addition, given the limited statistical models, machine learning models or physical machine capacity, as well as other coupled reactions that models. With measurements and desired outcomes, the are subject to limitations, feasible machine operations recommended adjustments to the conditioning variables are constrained. Improving drive performance therefore to move from current outcomes to desired outcomes can involves solving a constrained, nonconvex optimization be computed using the established relationships. problem that is solvable with a heuristic method. The mathematical framework for computing recommended adjustments can come from physics- and Sensing. Many machine operations and reactions are mechanics-based models (e.g., Yu et al., 2017) or from measured on modern EPB shield machines. For operations, machine learning-based models (Mooney et al., 2018). these include the individual thrust and articulation jack With the former, the chamber pressure response is forces, cutterhead and screw conveyor rotation speeds, and predicted based on TBM operations and conditioning the material injection rates of foam, bentonite, water and inputs. Given the complexity of the EPBM/ground/ polymer. For machine reactions, advance rate, alignment conditioning interaction, the modeled and measured deviations, chamber pressure and its distribution,

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cutterhead torque, screw conveyor torque and pressure where EPB shield operations X include the individual are all measured. However, there are still performance thrust jack forces Fi, cutterhead rotation speed ω, screw metrics that are unrecorded. A major limitation is the lack conveyor rotation speed ωs, as well as foam air and of sensing in the critical tool gap, cutterhead openings and solution injection rates Qair, Qsol. is the estimated excavation chamber areas. Further, continuous cutting tool advance rate to maximize and is a function of Fi, ω, wear is rarely measured on EPB shield machines, making it estimated cutterhead torque T̑ and estimated chamber hard to quantify wear rates under different operations. This pressure p̑ . Given the challenge of physics-based modeling, can be solved by adding wired or wireless sensors to the can be obtained with machine learning using data cutting bits. Another common issue is the lack of proper recorded on previous rings as well as geotechnical sensor calibration (e.g., thrust jacks) and inadequate information (Mooney et al., 2018). In addition, T̑ and p̑ sampling frequency (e.g., torque measurement), both are explicitly modeled and considered as optimization impacting the data quality and their usage for downstream constraints. For example, the estimated value of chamber processing. pressure p̑ should be within the tunneling face pressure ̑ bounds [pmin, pmax]. Estimated cutterhead torque T must Planning. To perform optimal control, both the not exceed the capacity of the torque motors. Cutterhead performance objective and all coupled machine reactions torque can be estimated using physics-based models are modeled. Take the advance rate maximization as (Godinez et al., 2015). A similar situation applies to the an example, its optimal control formulation is given as FIR and FER. Finally, individual thrust jack force Fi, follows: cutterhead rotation speed ω, and screw conveyor rotation

speed ωs all have their own mechanical limits set by interlocks and are all treated as constraints. The objective function and the constraints are nonconvex; therefore, solving the optimization above requires heuristic strategies such as particle swarm optimization.

Action. Formulations like the one above can be deployed for EPBM shield optimal control, though issues such as computation efficiency need to be addressed properly to

Fig.5 Diagram showing the performance of the AR model, learned using support vector regression. The training was conducted on the first 20 rings (#1001-1020) and was then tested on the following 20 rings.

44 may 2020 Tunneling & Underground Construction ® tuc&

Fig.6 Schematic layout of the environment perception framework for autonomous TBM tunneling.

yield the control in real time. Figure 5 presents one example CLASSIFIEDS ̑ where a predictive model, = f(Fi, ω, p̑ , T) was trained with a support vector regression model using the previous 20 rings worth of EPB shield data. The model performance is good, with R2 = 0.75 and RMSE = 5.92 mm/min. The BUSINESS OFFICE PRESS RELEASES model, in this example, was then used to predict performance SME - 8307 Shaffer Parkway Steve Kral Littleton, CO 80127 [email protected] over the subsequent 20 rings using the EPB shield inputs 800-763-3132 • Advertising: x243 actually adopted. As shown in Fig. 5, its performance is still Direct: 303-948-4243 acceptable, with an R2 = 0.65 and RMSE = 7.06 mm/min. In Fax: 303-973-3845 ADVERTISING AND www.smenet.org PRODUCTION/ addition to this example, the model provides as output a suite MEDIA MANAGER of input parameters to maximize AR. The input parameters EDITOR Johanna McGinnis are implemented via PID control on the EPB TBM. Steve Kral [email protected] It is worth noting that there are myriad supporting [email protected] operations as well as logistics that must be adequately Rock Splitting Mortar PRODUCTION DESIGNER  SENIOR EDITOR functioning to enable autonomous operations. These include D -mite Fractures Rock and Concrete in No Blast Conditions Bill Gleason Nate Hurianek [email protected] material batching (e.g., grout, bentonite, conditioners, D-mite aids and accelerates mechanical rock excavation [email protected] consumables resupply, umbilical extensions, segment No fly rock, no vibration, no noise, transport and mucking operations, to name a few). Some, Applications: Boulders, mass rock, tunneling, concrete removal if not all, of these can be made autonomous. Ideally, these operations are taken off the tunneling critical path. DAIGH COMPANY, INC. Tunneling & Underground Construction is supported 2393 Canton Hwy, Ste 400, Cumming, GA 30040 Geotech environment perception Office: 770-886-4711, Fax: 770-887-3783 by leaders in the underground industry. Please The ground plays a significant role in autonomous TBM www.daighcompany.com [email protected] tunneling. This environment is akin to the road network and patronize them and mention their ad in T&UC. spatial obstacle array in the area around an AV. A major concern and constraint for autonomous TBM tunneling is the fact that the spatial characterization of ground conditions along and above a tunnel project alignment is highly ADVERTISING SALES OFFICES uncertain. A related uncertainty lies in the behavior of the ground (e.g., uncertainty in shear strength, deformation and HOOPER JONES excess pore water-pressure generation). Efforts to advance CENTRAL, NW U.S. autonomous TBM tunneling, therefore, must implement ways 847-486 -1021 • Cell: 847-903-1853 • Fax: 847-486-1025 [email protected] ADVERTISERTunneling & Underground ConstructionPAGE may NO. 2020 45 MARSHA TABB EAST, SOUTH, WEST U.S. 215-794-3442 • Fax: 215-794-2247 AKKERMAN, INC...... 9 [email protected]

BRIERLEY ASSOCIATES ...... 17 LEWIS BONDER CANADA 514-485-3083 • Fax: 514-487-0553 CELLULAR CONCRETE LLC ...... 15 [email protected] blank doc.indd 1 5/23/07 1:23:40 PM DAVID R. KLUG & ASSOCIATES, INC...... 7 PATRICK CONNOLLY U.K. AND EUROPE GEOKON ...... 6 44 1702-477341 • Fax: 44 1702-477559 [email protected] HC GLOBAL ...... BACK COVER, 12 GUNTER SCHNEIDER SCANDIN. / EUROPE JACOBS ASSOCIATES ...... 17 49 2131-511801 • 49 2131-4038973 [email protected] JENNMAR CORPORATION ...... 14 JOHANNA MCGINNIS MINING EQUIPMENT, LTD ...... 13 ASIA, RUSSIA, UKRAINE, AFRICA, MID. EAST, LATIN AMER., AUSTRALIA 303-948-4243 • Fax: 303-973-3845 STRATA SAFETY PRODUCTS, INC...... 16 [email protected] WWW.TUCMAGAZINE.COM

46 MARCH 2009 T&UC

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to correctly capture spatial geotechnical uncertainty and use updated knowledge of the excavation environment. Figure 6 data to continuously update geotechnical conditions. This presents a general environment perception framework for updating of geotechnical conditions is similar to updating autonomous TBM tunneling. road conditions performed in concert with AV technology (described earlier). Conclusions Updating the ground condition can be realized by Autonomous vehicles (AVs) provide a compelling road using geostatistical models, machine-learning models or map for autonomous TBM advancement. With a well-thought- a combination of the two. Geostatistical models enable a out structure for autonomy and AVs currently at level 3 (of spatial estimation of the geological-geotechnical conditions 6), AV technology development has been remarkable, and at unsampled locations and help quantify spatial uncertainty. fully autonomous AVs are anticipated within the next decade. A 3D rendering of the geological-geotechnical environment, Using the AV framework of sensing (perception)–planning– developed using the geotechnical site investigation and action (control), this paper has described the various EPM associated laboratory testing results, will be fed into the TBM subsystems that are currently partially automated or can local area network (LAN) for the autonomous TBM to use. become autonomous in the future. As with AVs, the biggest TBM operation parameters can be used to estimate the hurdle to autonomous TBM tunneling is sensing, particularly as-encountered ground conditions using machine-learning in the critical areas immediately ahead of the cutterhead, at models. Additionally, instrumentation and monitoring (I&M) the cutterhead and through the excavation chamber and screw data can be back-analyzed using suitable machine-learning conveyor. Advances in the sensing of these areas is required to algorithms and physics models to estimate the ground drive autonomous TBM technology. conditions within the zone of influence. Integrating the Nontechnical aspects of AVs and autonomous TBM prior-to-construction estimates of geological-geotechnical tunneling include human trust, liability and regulation. Volvo, conditions from geostatistical modeling and preposterior for example, has stated it will accept all liability with its AVs. estimates from TBM and I&M data can aid in continuously The liability associated with autonomous TBM tunneling will updating the geological-geotechnical environment along be a significant barrier (e.g., Who will accept this risk and how the tunnel alignment. The process can enable TBMs to gain will this liability be underwritten?). Owner acceptance and

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regulation will also require development (e.g., Under what of robotics in the mineral raw materials sector-an overview, 2018 IEEE/RSJ Interna- conditions will owners permit autonomous TBM operations in tional Conference on Intelligent Robots and Systems (IROS). IEEE, pp. 1507-1512. urban environments?). n Martin, D., 1990. JAPANESE ROBOT CAN ERECT SEGMENTS. Tunnels & Tunnelling International 22. References McLane, R., 2014. Automatic Soil Conditioning Through Clay. North American Aryal, M., 2018. Object Detection, Classification, and Tracking for Autonomous Vehicle. Tunneling: 2014 Proceedings. Camus, T., Moubarak, S., 2015. Maintenance robotics in TBM tunnelling, ISARC. Mokhtari, S., Navidi, W., and Mooney, M.A. White Box Regression (Elastic Net) Proceedings of the International Symposium on Automation and Robotics in Con- Modeling of Earth Pressure Balance Shield Machine Advance Rate, Automation struction. IAARC Publications, p. 1. in Construction, 2020, 115(103208), https://doi.org/10.1016/j.autcon.2020.103208. de Wardt, J., Chapman, C.D., Behounek, M., 2012. Well Construction Automation- Mooney, M., Yu, H., Mokhtari, S., Zhang, X., Zhou, X., Alavi, E., Smiley, L., Hodder, Preparing for the Big Jump. W., 2018. EPB TBM Performance Prediction on the University Link U230 Project. de Wardt, J.P., Sheridan, T.B., DiFiore, A., 2016. Human Systems Integration: Key North American Tunneling 2018 Proceedings. Enabler for Improved Driller Performance and Successful Automation Application, Mooney, M.A., Walter, B., Frenzel, C., 2012. Real-time tunnel boring machine monitor- IADC/SPE Drilling Conference and Exhibition. Society of Petroleum Engineers. ing: A state of the art review. North American Tunnelling, 2012 Proceedings, 73-81. Estl, H., 2018. How ADAS Is Paving the Way for Autonomous Driving (https:// Rogers, W.P., Kahraman, M.M., Drews, F.A., Powell, K., Haight, J.M., Wang, Y., Baxla, www.5gtechnologyworld.com/how-adas-is-paving-the-way-for-autonomous-driving/). K., Sobalkar, M., 2019. Automation in the Mining Industry: Review of Technology, Etherington, D,. 2019. Over 1,400 self-driving vehicles are now in testing by 80+ Systems, Human Factors, and Political Risk. Mining, Metallurgy & Exploration, 1-25. companies across the US. Retrieved from https://techcrunch.com/2019/06/11/over- Rosique, F., Navarro, P.J., Fernández, C., Padilla, A., 2019. A systematic review of 1400-self-driving-vehicles-are-now-in-testing-by-80-companies-across-the-u-s/ perception system and simulators for autonomous vehicles research. Sensors 19, 648. Galanis, I., Gurunathan, P., Burkard, D., Anagnostopoulos, I., 2018. Weather-based Schwob, A., Guedon, F., Combe, B., Lockhart, T., 2019. Tuen Mun–Chek Lap Kok Link road condition estimation in the era of Internet-of-Vehicles (IoV), 2018 IEEE Inter- in Hong Kong–Innovative solutions for construction of an outstanding Subsea Tunnel, national Symposium on Circuits and Systems (ISCAS). IEEE, pp. 1-5. Tunnels and Underground Cities. Engineering and Innovation Meet Archaeology, Godinez, R., Yu, H., Mooney, M., Gharahbagh, E.A., Frank, G., 2015. Earth Pressure Architecture and Art. CRC Press, pp. 3086-3096. Shimz Corporation, 2018. AI-based Support System Developed for Shield Excava- Balance Machine Cutterhead Torque Modeling: Learning from Machine Data, Rapid tion Planning. excavation and tunneling conference, New Orleans. Shirlaw, J.N., Richards, D.P., Ramond, P., Longchamp, P., 2004. Recent experience in Insurance Information Institute, 2019. Facts + Statistics: Highway safety (https://www. automatic tail void grouting with soft ground tunnel boring machines, Proceedings iii.org/fact-statistic/facts-statistics-highway-safety). of the ITA-AITES World Tunnel Congress, Singapore, pp. 22-27. Jacobs, T., 2015. Automated Drilling Technologies Showing Promise. SPE-0615- Wu, C., Liu, X.-J., Wang, L.-P., Wang, J., 2011. Dimension optimization of an orientation 0050-JPT 67, 50-55. fine-tuning manipulator for segment assembly robots in shield tunneling machines. Kinik, K., Gumus, F., Osayande, N., 2014. A case study: first field application of fully Automation in Construction 20, 353-359. automated kick detection and control by MPD system in western Canada, SPE/IADC Yu, H., Mooney, M., Bezuijen, A., 2017. A Simplified Chamber Pressure Model for Managed Pressure Drilling & Underbalanced Operations Conference & Exhibition. EPB TBM Tunneling in Granular Soil, in: Jr., A.N., Jr., M.O.C. (Eds.), 9th Interna- Society of Petroleum Engineers. tional Symposium on Geotechnical Aspects of Underground Construction in Soft Kockelman, et al., 2017. An assessment of autonomous vehicles: traffic impacts and Ground, Sao Paulo. Yurtsever, E., Lambert, J., Carballo, A., Takeda, K., 2019. A Survey of Autono- infrastructureT&UC needs ad - finalAugust report. 2019.pdf Report FHWA/TX-17/0-6847-1, 1 8/15/19 8:05 182AM p. mous Driving: Common Practices and Emerging Technologies. arXiv preprint Lopes, L., Miklovicz, T., Bakker, E., Milosevic, Z., 2018. The benefits and challenges arXiv:1906.05113.

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Tunneling & Underground Construction may 2020 47 ® tuc& Feature Article 3 Tunnel-boring machines for Norwegian small hydropower projects

orway has a long history in Fig.1 hydropower and has a yearly Power production by percentage in Norway (Normal year, OED, 2019). Nproduction of 135 terawatt hours (TWh) distributed across more than 1,600 hydroelectric power plants. This production capacity covers more than 94 percent of the total electricity usage in the country. The vast majority of power plants in Norway were built before 1990, and more than 200 km (124 miles) of associated tunnels were excavated by tunnel-boring machines (TBM) during Norway’s big hydropower era stretching from the late 1960s to the early 1990s. As a larger degree of Norwegian rivers, streams and waterfalls were tamed for hydropower, public resistance grew against hydropower projects. In the mid-1990s, then-Norwegian Prime Minister Jens Stoltenberg declared that the era of big hydropower construction was over. Nevertheless, the Norwegian topography and water resources still represented a major potential for construction is cost efficient and quicker, and the initial hydropower, especially if a solution with less impact investment required is lower. The widespread availability on the environment could be found. One of these of locations where these projects can be built also offers a solutions included small hydropower projects, defined as great distribution of value generation across all parts of the hydropower plants with an installed capacity of less than country (Smakraftforeninga, 2016). 10 MW. This article addresses why small hydropower projects Construction of small hydropower projects. A are a great way of generating electrical energy and why significant number of the existing small hydroelectric mechanized tunneling is a beneficial way of making them. power projects (SHEPPs) had been constructed either with pipes on the surface or by trenching. In recent years it Small hydropower projects and why they matter. There has been a general trend that larger parts of these SHEPPs are currently more than 1,300 small hydropower plants are built in tunnels, either due to the topography or to operating in Norway with an installed yearly production reduce the environmental impact even more. of 11 TWh. The small hydro share of the total power In small hydroelectric projects that require an production is currently around 11 percent (Fig.1). underground waterway, the tunnel is usually built by one The local impact on nature of these small projects of the following methods: is generally lower than larger hydropower projects, • Trenching. Sindre Log, Rune Skjevdal and • Drill and blast tunneling. • Raise drilling. Tobias Anderson • Directional drilling. • TBM boring. Sindre Log, member UCA of SME, is civil engineer - product manager/cutters, The Robbins Company As a rule, trenching is the most cost-efficient solution and Rune Skjevdal and Tobias Anderson are chief for such projects. However, in many cases the topography executive officer and TBM chief, respectively, NGK and nature of the projects do not allow for trenching. If Boring, email [email protected]. a tunnel is needed, the other options have historically been between drill and blast tunneling, raise drilling or

48 may 2020 Tunneling & Underground Construction ® tuc&

Fig.2 Typical small hydro layout (Norhard.no). directional drilling or a combination of those methods. The SHEPPs that consist of a tunnel often have some physical constraints that limit the construction method:

1. There is naturally a big elevation difference between the tunnel portals. 2. There is generally as much overburden as is practically possible toward the downstream portal to avoid challenging geology, hydraulic fracking and hydraulic jacking, and to Fig.3 lower costs. Typical small hydro layout (Norhard.no). These limitations mean that the vertical profile of a SHEPP tunnel is often similar to Fig. 2, with limited inclination in the downstream portal and high inclination toward the upstream portal. The traditional way of constructing such projects has been to drill and blast the flat part and raise bore the incline. A concrete plug is installed where hydraulic jacking forces are lower than the minor principle stress in the surrounding rock and further through a pipe in the

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Fig.4 tunnel toward the powerhouse. The most common blasted Norhard breakthrough with pilot hole on Grytendal project cross section is between 16 and 25 m2 (175 and 269 sq ft) (NGK, 2019). due to limitations in the available equipment as well as the challenges of excavating efficiently with drill and blast at diameters smaller than 16 m2 (175 sq ft). If the tunnel was to be excavated with other methods, a profile like Fig. 3 would be typical. The alternative to the conventional method has been directional drilling performed with a heavily customized directional drilling rig such as that devised by Norwegian company Norhard AS. The Norhard drilling rig consists of a pilot tri-con bit for drilling with carbide raise drill cutters to ream up the diameter of about 0.7 m (2.2 ft). The hole can then be reamed up with several drillings up to a diameter of 1.5 m (5 ft). The drill string is powered by a nonrotational drill string from the outside (Fig. 4). As the SHEPPs have become increasingly complex, TBMs have been introduced on several projects in Norway in recent years as an excavation method that has its own unique benefits.

Benefits of mechanized tunneling for hydropower. Mechanized tunneling offers some significant advantages on unlined hydroelectric power projects: a tunnel with a TBM instead of blasting it. The theory • Reduction of needed cross section due to lower behind this result is that a lot of the rock support in blasted surface roughness. tunnels with small cross sections is installed to stabilize • Better tunnel quality, resulting in less rock support rock that has been damaged by the blasting. The TBM- and lower lifecycle costs. bored tunnel walls are less damaged, which also increases • Less impact on the environment. tunnel quality, ultimately leading to lower maintenance • Reduction of tunnel construction time. cost of the tunnels and longer tunnel life. Also, the smaller Due to the lower surface roughness Fig.5 of the tunnel wall in a mechanically Reduction of theoretical cross section with mechanized tunneling (Log, modi- excavated tunnel, the water flows better fied based on NTNU, 1998). and the needed theoretical cross section can be reduced by 40-60 percent. A more detailed graph is given in Fig. 5. The more efficient water flow, and the capability of using the tunnel as the water-carrying pipe, reduces the need for excavated material significantly. This means less excavated material needs to be removed and stored and is also economically advantageous. Less rock support is required in general in mechanically excavated tunnels, and because of the better tunnel quality, there are lower lifecycle costs to maintain the tunnel. Mechanized tunneling also disturbs the environment far less than drill and blast operations. The empirical data from TBM-excavated hydropower projects in Norway support these points. Results show that there is a reduction in installed rock support of between 40 and 90 percent when boring

50 may 2020 Tunneling & Underground Construction ® tuc&

Fig.6 Double Shield Rockhead at Holen SHEPP. (Photo: Endre and horizontal curvature. Hilleren) 4. Some of the projects have limited space on site and no road access at the upstream portal. 5. The length of the tunnel is typically between 500 and 3,000 m (1,640 and 9,800 ft). 6. The budgets for these projects are often extremely limited.

These challenges require a unique TBM design:

1. The TBM needs to be small but still equipped with sufficient cutter sizes to efficiently break the rock. 2. The TBM cutter diameters must be as large as possible and the highest quality disc ring material must be used to reduce cutter changes due to the limited space. 3. The machine needs to be able to negotiate steep inclines and the transitions between inclines. 4. The TBM needs to be able to backtrack through the tunnel. 5. The TBM must be optimized to be used on several projects with limited service time in between. tunnel dimension and the circularity of the hole increases 6. The TBM package needs to be economically the stability of the rock and decreases the need for rock viable. support. Excavation with TBMs also offers several environmental advantages. The EBRATIN EL G TBM and muck haulage are typically C run on 100 percent electric power from the grid, which in Norway consists of 94  percent renewable energy. In addition to the already-mentioned environmental aspects that include reduced excavated material, mechanized tunneling eliminates the risk of nitrous run-off and plastic waste that are present in drill and blast material deposits.   TBMs for small hydropower For the past 10 years there has been interest from owners, contractors and the government to develop TBM Model 4500S solutions for some of the upcoming Standard Piezometer SHEPPs in Norway. From a TBM design perspective, there are some special challenges of the Norwegian SHEPPs: GEOKON maintains a stock SAME DAY of many commonly used 1. The theoretically needed cross instruments. Contact us to fi nd out what we can send section is usually very small and SCAN ME requires TBMs smaller than 3 m with same day shipping. (10 ft). 2. Norwegian rock is often Producing Quality Geotechnical extremely hard. Instrumentation Since 1979. 3. The geometry of the projects www.geokon.biz/TUC is often challenging, with the | Lebanon, NH, USA tunnels often containing high +1.603.448.1562 | [email protected] inclines, combined with vertical

Tunneling & Underground Construction may 2020 51 ® tuc&

Fig.7 Breakthough at Holen SHEPP (Photo: Hardanger Maskin AS). upward tilt to 45 degrees at the breakthrough. The Rockhead launched in July 2018 with Robbins Field Service onsite assisting Hardanger Maskin AS with assembly, setup and launch of the equipment. As tunneling began, the slope was near horizontal, but as the tunnel got steeper, the special safety gripper system came into use. The safety gripper system was designed with interlocks to ensure primary grippers were never released while the safety grippers were engaged and with an additional safety mechanism that allowed for mechanical locking in the event that hydraulic pressure was lost. While the excavation rate of the machine was good, the novel design experienced some reliability issues during tunneling in the hard granite. Despite the challenges, the machine completed a daring hole-through at a steep 45-degree incline on Jan. 1, 2019. It has since been relaunched to bore its second 640 m (2,100 ft)-long tunnel, where the design continues to be fine-tuned (Fig. 7).

Unique TBM and conveyor solutions: Salvasskardelva SHEPP. The other solution, based on more standard TBM technology, came into use in the summer of 2019. Robbins supplied the 2.8 m (10 ft)-diameter specialized main-beam TBM, Snøhvit, to Norsk Grønnkraft to use on several of their hydroelectric tunnels. In addition to investing in a TBM, Norsk Grønnkraft also started a specialized contracting company, NGK Boring, that entered into a cooperation with Entreprenørservice AS to construct the tunnels. The first tunnel, the 2.8 km (1.7 mile)-long 7. The TBM might need to be able to launch from a Salvasskardelva SHEPP located in Bardu, Norway, has a limited space area. modest positive gradient of 5.2 percent. To combat boring on a grade, the small main-beam TBM was designed for This led Robbins to develop two separate solutions for adaptability with an option to add a safety gripper on the Norwegian hydro projects. One was based on small future tunnels for boring at high inclines. boring units (SBU), a line of trenchless boring equipment The TBM is equipped with nineteen 432-mm (17-in.) and machinery typically 2 m (6.6 ft) or smaller in diameter, cutters with a load rating of 267 kN each (Fig. 8). The 2.8 while the other used more standard TBM technology. m (1.7 ft)-diameter cutterhead is powered by four 210-kW variable frequency drives (VFDs). Small-diameter design: Holen hydropower. The first A continuous conveyor was provided for muck tunneling machine for SHEPPs was ordered by Hardanger removal, making it the smallest conveyor belt Robbins Maskin AS, for the project Holen Hydropower owned by has ever provided. The 450 mm (18 in.)-wide conveyor Smaakraft AS in early 2018. belt will need to travel through curves, which begin at the Robbins developed a new solution for the project 650-m (2,132-ft) mark at Salvasskardelva. The structure using well-proven SBU technology. The Double Shield was designed to minimize muck spillage in curves despite Rockhead (SBU-RHDS) provided for the tunnel includes its narrow width and is within its design limits. The small 360 cm (14 in.)-diameter cutters and is capable of self- jobsite also required the use of a double-stack belt storage propelled excavation using a gripper system. cassette standing 5 m (16 ft) tall. The unique system is The novel 2 m (78 in.)-diameter machine is equipped planned to be reused at each of the tunnel sites. with unique features that allow it to drill at a steep incline, NGK and Robbins worked together during the design including electric power, modified oil and lubrication period to design a launch frame instead of excavating systems and a fail-safe safety gripper (secondary gripper), a starter tunnel, which allowed the machine to advance as well as a water-based spoil removal system, developed until it was well enough into the tunnel to grip the tunnel by the contractor (Fig. 6). walls. The launch frame is planned for reuse on subsequent Due to local terrain, the tunnels had a small launch tunnels. area of 4 × 10 m (13 × 33 ft) and the tunnel slope on As of December 2019, the TBM had surpassed the the first 640 m (2,100 ft)-long drive ranged from a slight 1,300-m (4,265-ft) mark, and the machine was excavating

52 may 2020 Tunneling & Underground Construction ® tuc&

Fig.8 Crown-mounted conveyor at Salvasskardelva.

well in mica gneiss and schist rock, achieving rates above 100 mm (3.9 in.) per minute. TM Small-diameter hydro tunneling looks poised to continue making a big DigitalBRIDGE impact in Norway. A third TBM, a 2.6 m (8.5 ft)-diameter Robbins Double Bridging Power & Data to the Shield TBM with a safety gripper, began Edges of your Operation excavation in the winter of 2019 at the Tokagjelet SHEPP. The alignment of the 2.2 km (1.4 mile)-long tunnel will increase gradually from near-horizontal • VOICE to a 45-degree incline. • VIDEO Conclusions • TELEMETRY Hydroelectric power generation has historically required high investments and mountainous topography with water in abundance. Unfortunately, the sizes and complexity of traditional hydropower projects also tended to have a negative impact on the surrounding environment. The small hydro project approach introduces an opportunity to construct renewable energy with limited investment and limited negative consequences on the local environment. 800-691-6601 • www.strataworldwide.com Given the increasing interest in small hydro tunnels and the fine-tuning of effective designs for rock tunnels See us at NAT2020 Show Booth 1204 at steep inclines, there is a huge

Tunneling & Underground Construction may 2020 53

Strata-DigitalBRIDGE-Ad_114mmx122mm_NAT.indd 1 2/14/20 7:33 AM ® tuc&

potential for continued projects in Norway and in other large waterfalls and high mountains that big hydropower locations such as the United States. Renewable energy schemes require. n with a reduced initial investment and construction time could become essential wherever the terrain is hilly or References mountainous and water features abound. SSB (2016). Kryssløpstabeller - ESA Questionnaire 1850 - Symmetric Infrastructure spending, particularly on water tunnels, input-output table for domestic production (industry*industry). Til- is on the rise in the United States, and it is believed that gjengelig på https://ssb.no/en/nasjonalregnskap-ogkonjunkturer/tables/ there is a tremendous potential for small hydropower supply-and-use-and-input-output projects in North America. Small hydropower is likely Småkraftforeninga (2016).“Samfunnsnytte av småkraft”. Thema Con- sulting group to become more popular as it offers the best of several NTNU (1998). NTNU-Anleggsdrift: Project Report 1A-98 HARD worlds. It is an environmentally friendly way of generating ROCK TUNNEL BORING Design and Construction. power, is less taxing on natural resources and is cost- Norhard (2019). Pictures from Norhard.no effective and quick to implement. It does not require the NGK (2019). Picture courtesy of Norsk Grønnkraft

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54 may 2020 Tunneling & Underground Construction ® tuc& NEWSNEWSNEWS

Work on Hampton Roads Bridge-Tunnel project gets underway ork on the $3.8 billion the United States and is scheduled to and extensive negotiations by our Hampton Roads Bridge- launch from the South Island in about dedicated teams over the past year to WTunnel in Hampton Roads, a year and a half. deliver significant improvements to VA is underway and has not been The Hampton Roads Bridge- reduce daily congestion, increase safety, halted by the COVID-19 pandemic. Tunnel expansion is projected to and enhance connectivity throughout When the project is completed in bolster the economic competitiveness this key corridor.” 2025, there will be two, new two-lane of the Hampton Roads region with The Hampton Roads tunnels in addition to the existing ones. more than $4.6 billion in investments Transportation Accountability Interstate 64 will also be widened on and a projected 28,000 new jobs over Commission, a regional financing both sides of the tunnel. the life of the project. entity, will pay for $3.56 billion of the Paula Miller, a spokeswoman for “The largest project in project cost. That money comes from the project, said crews are working VDOT history, this expansion will an existing regional surcharge on fuel on the early stages of the project and address some of our most pressing taxes and sales taxes. are putting up new power poles and transportation challenges and unlock VDOT will kick in $200 million fixing existing ones. This is to prepare opportunity for families, military from its so-called “Smart Scale” for more electrical current to power a personnel and businesses, not only in financing program and $109 million tunnel-boring machine (TBM). the Hampton Roads region but across from a special fund for critical projects, The Virginia Department of the Commonwealth,” said Virginia Gov. to be used to replace trestles that carry Transportation (VDOT) officials said Ralph Northam. “These agreements the roadway on the Norfolk side of the it’s the second-largest TBM used in are a culmination of the diligent work bridge-tunnel. n

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4 maY 2020 Tunneling & Underground Construction DERRICK MUD RECYCLING TECHNOLOGY PATENTED SCREEN SURFACES I COMPLETE SYSTEMS I SOLIDS REMOVAL EQUIPMENT

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GLOBAL HEADQUARTERS • (412)-963-9071 • PITTSBURGH, PA USA • WWW.JENNMAR.COM ® tuc& NEWSNEWSNEWS Purple Line Extension TBM reaches Wilshire/Fairfax station ne of the tunnel-boring second TBM, named Soyeon, was “This has been an enormously machines (TBM) working expected to reach Wilshire/Fairfax in complex operation that Metro and Oon Section 1 of the Metro about eight weeks. its contractor, Skanska Traylor-Shea, Purple Line Extension Project in Los Reaching this milestone is a have successfully conducted,” city Angeles, CA reached the Wilshire/ significant accomplishment for Metro. of Inglewood Mayor and Metro Fairfax subway station near the La The underground soil conditions in Board Chair James T. Butts said in Brea Tar Pits in the Miracle Mile. It this area of Los Angeles represent a statement. “When this project is is the second station that LA Metro some of the most challenging for the ultimately completed, we will have has successfully reached via tunnel as entire project. The agency’s modern, fast, frequent and reliable subway part of Section 1. high-tech TBMs have mined through service connecting downtown L.A. The TBM, a 907-t (1,000-st), a unique combination of soils and and West L.A. in just 25 minutes. That 122-m (400-ft) machine, named geologic conditions, including tar will be a game changer for all of L.A. Elsie, started at the Wilshire/La sands and methane gas. County.” Brea station in October 2019 and The breakthrough also marks Public works projects like the broke through the eastern side of another milepost in the decades- Purple Line Extension project the planned Wilshire/Fairfax station long effort to extend LA Metro’s are considered essential activities site about 1.6 km (1 mile) away on subway farther west beneath Wilshire during the COVID-19 public health April 4. The TBM is now resting Boulevard, one of the busiest and crisis. Metro and its contractors are approximately 21 m (70 ft) below most congested urban thoroughfares committed to ensuring the safety of busy Wilshire Boulevard. Metro’s in the United States. (Continued on page 12)

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8 maY 2020 Tunneling & Underground Construction ® tuc& NEWSNEWSNEWS

Contractors chosen for Great Lakes tunnel project nbridge Inc. announced that Gov. Rick Snyder’s administration AB, Canada, planned to provide a it has hired companies to to drill the tunnel through status report to the Mackinac Straits Edesign and build a disputed oil bedrock beneath the straits. The Corridor Authority during a meeting pipeline tunnel beneath the channel case is before the state Court of in St. Ignace, MI. The panel was linking Lakes Huron and Michigan, Appeals, which declined to put the established by the law that approved despite pending legal challenges. lower court ruling on hold while the tunnel agreement. The Canadian company is considering the matter. Great Lakes Tunnel Constructors, forging ahead with plans to begin Nessel, a Democrat, also has a partnership between Jay Dee construction work in 2021 on the filed a separate lawsuit seeking to Contractors Inc. of Livonia, MI, Great Lakes tunnel project, which shut down Enbridge’s existing Line and the U.S. affiliate of Japan-based would replace twin pipes that have 5 pipes. Obayashi Corp., will build the tunnel. lain across the bottom of the Straits But the company believes its Arup, a multinational engineering of Mackinac in northern Michigan success in court thus far creates “a company based in London, will since 1953. path forward,” spokesman Ryan design it, Enbridge said in a The Associated Press reported Duffy said. statement. that State Attorney General Dana “We feel like it’s time now for Line 5 each day carries 87 million Nessel is appealing a Michigan Enbridge and the state to work L (23 million gal) of crude oil and Court of Claims ruling last October together and keep the project natural gas liquids used for propane that upheld an agreement between moving,” he said. between Superior, WI, and Sarnia, Enbridge and former Republican Enbridge, based in Calgary, (Continued on page 16) MINEVENT® Layflat Blower Ducting

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Tunneling & Underground Construction maY 2020 9 ® & tuc Design NEWSNEWSNEWS with Vision Funding plan for Ottawa tunnel announced Build with ntario, Canada’s Premier that provides benefits for all Integrity Doug Ford, along with transit riders and taxpayers,” said OCaroline Mulroney, Mulroney. “These subway projects Minister of Transportation, and in Scarborough and along Eglinton Kinga Surma, Associate Minister of will strengthen our transit network Transportation, invited the federal and better connect us as a world- government to join the province to class province, region and city.” fund at least 40 percent of the four “We’ve worked diligently to subway projects being built in the make great strides in building greater Toronto area. The projects transit, creating a transit plan, include the Scarborough Extension establishing a historic Ontario- and the Elington Crosstown West Toronto Transit Partnership Extension. agreement with the city and “Our government has a plan introducing legislation to build to build Ontario together and has transit faster,” said Kinga Surma, joined a coalition of municipal Associate Minister of Transportation. partners to build some of the most “Now it’s time to get shovels in ambitious, historic and nationally the ground and place orders for significant projects in the country,” tunnel-boring machines to expand said Ford. “We have made our subway system by more than 50 tremendous progress in the past percent. Our government is moving working with our federal partners, at an unprecedented pace to deliver and we can do it again with our on the premier’s transit vision for rapid transit plan, which includes the province.” four subways. I firmly believe these “Our government has made projects will not only move Ontario transit and transportation forward but will move the entire infrastructure a marquee part of country forward.” our plan for Ontario,” said Laurie The invitation to the federal Scott, Minister of Infrastructure. government comes as the Ontario “We are moving forward with the government announced the most significant transit projects first phase of construction and the Greater Toronto Area has tunneling work for two priority experienced in generations and all transit projects — the three-stop of these projects will be delivered Scarborough Subway Extension using Ontario’s world-class UNDERGROUND and the Eglinton Crosstown West public-private partnership (P3) Extension with planned connection model. Today marks an exciting ENGINEERING to Pearson International Airport, milestone for two of the priority McMillen Jacobs Associates the second-largest employment transit projects the three-stop brings decades of highly zone in Canada. Scarborough Subway Extension technical expertise in engineering, Two Requests for Qualifications and the Eglinton Crosstown West environmental, and construction (RFQs) were issued, through Extension. It’s another example services to any transportation, Infrastructure Ontario (IO) and that Ontario is getting shovels in water, wastewater, hydropower, Metrolinx. They mark the first the ground and we are delivering on and heavy civil project. step in the procurement process our plan.” to deliver on the province’s These RFQs outline the scope commitment to build transit faster, of work to design, build and finance eliminate gridlock and connect the construction of tunnels for the people to places and jobs. three-stop Scarborough subway and “We are building a modern, Eglinton Crosstown West Extension. mcmjac.com efficient rapid transit system (Continued on page 15)

10 maY 2020 Tunneling & Underground Construction ® tuc& NEWSNEWSNEWS DC Water’s Potomac River Tunnel proposal approved by National Park Service he U.S. National Park Service the Potomac River and convey the District of Columbia, the U.S. on April 14 approved DC them to the Blue Plains Advanced Environmental Protection Agency TWater’s proposal to move Wastewater Treatment Plan for (EPA), and the U.S. Department of forward with construction of the treatment. Justice, as amended January 2016, Potomac River Tunnel project Combined sewers are designed DC Water said in a statement. following an environmental to collect rainwater runoff, domestic It’s not just rainwater that ends assessment. sewage and industrial wastewater up in the overflow — there can also The Potomac River Tunnel in the same pipe and transport it to be untreated human and industrial project — part of DC Water’s Clean a treatment plant. During severe waste, toxic materials and debris, Rivers Project — is estimated to weather, like heavy rainfall or according to the EPA. reduce combined sewer overflow snowmelt, those systems can get The Potomac River Tunnel volume into the Potomac River overwhelmed and the overflow ends project aims to combat that. by 93 percent, according to a news up in nearby streams or rivers. In addition to reduced overflow release. The project is needed to by percentage, the project is The project consists of a large- reduce CSOs that contribute to estimated to reduce the frequency of diameter deep sewer tunnel, water quality impairment of the overflows from approximately 74 to diversion facilities, drop shafts Potomac River and, ultimately, the four in a year of average rainfall. and support structures to capture Chesapeake Bay; and to comply “The project includes flows from existing combined with the 2005 Federal Consent sewer overflows (CSOs) along Decree entered into by DC Water, (Continued on page 16)

Tunneling & Underground Construction maY 2020 11 ® tuc& NEWSNEWSNEWS Purple Line: Phase One on pace for 2023 completion (Continued from page 8) this project section, both of Metro’s is scheduled for completion in 2023. all project workers during this time. TBMs will have mined nearly half Section 2 of the Purple Line Elsie was originally lowered into a million cubic yards of earth — Extension Project will extend the the ground at Metro’s Wilshire/La the equivalent of filling 2.3 million subway to downtown Beverly Hills Brea station site in the Miracle Mile bathtubs with dirt. and Century City. Section 2 is also area of Wilshire in October 2018. “We are proving once again that currently under construction and is While advancing the TBM tunneled we can successfully mine through some scheduled for completion in 2025. about 19 m/d (60 ftpd). It worked five of the most challenging conditions Sections 1 and 2 are funded primarily days per week, 20 hours a day. It took that any subway project in the by Measure R — the sales tax Los about five months to tunnel from world is likely to face,” said Metro Angeles County voters approved in Wilshire/La Brea to Wilshire/Fairfax. chief executive officer Phillip A. 2008 — and with a pair of federal Metro’s TBMs are pressurized, Washington. “We have a world-class grants. closed-face machines that minimize team that includes Skanska-Traylor Section 3 will then extend the ground settlement during excavation. Shea. The team has international project to two stations in Westwood. The tunnel is lined with precast tunneling experience and has proven The passage of the Measure M sales concrete segments that are bolted it can also be safely done here in Los tax ballot measure by county voters together to form a ring. Segments Angeles.” in 2016 will allow this section to be are also gasketed to make the joints The project is being built in three accelerated. Construction began in between segments water- and gas- sections. The first section between 2019. Metro has secured federal funds tight. Wilshire/Western and Wilshire/La for the last section of the Purple Line When tunneling is finished for Cienega is now under construction and Extension Project. n

12 maY 2020 Tunneling & Underground Construction ® tuc& NEWSNEWSNEWS

North American Tunnel Conference cancelled he Underground Construction and lead the way in these uncertain of this issue, and the UCA is looking Association of the Society times.” into alternative ways to honor these Tfor Mining, Metallurgy & “It’s not the outcome we planned individuals. In addition, UCA is Exploration (UCA of SME) said it for, but certainly in the best interest taking content from NAT online was disappointed to announce that of everyone involved,” said Dave during the week of June 8. More the North America Tunneling (NAT) Kanagy, executive director of UCA of information will emailed to UCA 2020 Conference, originally scheduled SME. “We appreciate the hard work of SME members about this virtual to be held June 7-10 in Nashville, and dedication that our volunteers learning opportunity. In addition, the TN, was cancelled because of the have put in to develop another NAT proceedings will be published as COVID-19 pandemic. leading industry program. The UCA an eBook and available in the SME In a press release, the UCA of staff is currently looking into potential Bookstore in May. SME said, “It is with the safety of all virtual options to share some of those The UCA of SME continues to involved, coupled with the uncertainty much anticipated sessions.” More make plans for future conferences of what business and travel information can be found online at for the tunneling industry including environments will look like in June www.natconference.com. the Cutting Edge Conference Nov. that the difficult decision was made to During NAT, the UCA of SME 9-11 in Dallas, TX; the George A. Fox cancel this biennial event. presents its biennial awards in Conference in January 2021 in New “One of the core values of the Lifetime Achievement, Outstanding York City and the Rapid Excavation UCA of SME is health and safety, so Individual, Outstanding Educator & Tunneling Conference June 13-16, it is even more critical that we take and Project of the Year; those 2021 in Las Vegas, NV. measures to stay true to our principles winners are announced on page 55 The COVID-19 pandemic had spread around the world, infecting more than 2.4 million people and claiming the lives of more than TUNNELING SPECIALISTS bradshawcc.com 165,000 people near the time of 410.970.8300 the announcement. Global travel has been restricted and numerous By combining superior craftsmanship with innovative tunnel engineering and professional conferences have either construction technology, Bradshaw Construction Corporation successfully provides been postponed or cancelled. The cost effective tunneling solutions to the utility and transportation industries. World Tunnel Congress, which was originally scheduled for May 15-31 in Malaysia, has been rescheduled to PROVIDING INNOVATIVE SOLUTIONS Sept. 11-17. In Milan, Italy, Salini Impregilo FOR TUNNELING PROJECTS and Astaldi announced that work has resumed on the M4, the new metro line for Milan. Working with the city, M4 SpA and other operators involved in the project, necessary measures have been taken to protect the health of workers as they proceed with the strategic project for the city’s sustainable mobility. In order for the work to proceed, extraordinary safety measures have been adopted to protect the health of workers and microtunneling | tbm tunneling | hand tunneling | shaft work avoid contagion. About 200 workers returned to work on the $1.8 billion project. In the United States, work on BRADSHAW most projects has continued with .. CONSTRUCTION CORPORATION additional precautions in place for worker safety. n

Tunneling & Underground Construction maY 2020 13 ® tuc& NEWSNEWSNEWS TBM breaks through in Guangxi Province n January 2020, a Robbins The Robbins Main Beam TBM bored through limestone rock and installed a 5.97 m (19.6 ft)-diameter main full range of ground support, from rock bolts to ring beams and wire mesh. Ibeam TBM cleared its final hurdle when it broke through in Guangxi Province, China. The TBM excavated its first of two tunnels, an 11.9 km (7.4 mile)-long conduit for Lot 1 of the North Line Water Irrigation Project, Letan Water Reservoir, Drought-Relief. The tunnel was marked by a gauntlet of challenges, from karst cavities to fault zones and water inflows. The workers on the jobsite, contractor Guangdong No. 2 Hydropower Bureau Co., Ltd., and the owner, Construction Management Bureau for the Letan Water Reservoir, had much to celebrate after completion of what is widely regarded as the most complex and longest tunnel on the North Line project. Boring with the Robbins Main Beam TBM and continuous conveyor system began in the summer of 2015. “There was no precedent in this province for using a main beam TBM to excavate a tunnel longer than 10 km (6 miles). We didn’t have relevant local experience to use for reference,” explained Yongjiu Jin, deputy manager of the project for contractor Guangdong No. 2 Hydropower Bureau Co., Ltd. The machine did encounter a number of difficult geological obstacles as it bored through limestone rock but was still able to achieve advance rates up to 40 m/d (130 ftpd) in good ground. Much of the geology consisted of lightly weathered limestone in rock class II to III, with some Mixing and grouting equipment for ground sections in class IV to V rock that improvement, anchorages, reinforcing, required the heaviest amount of sealing, pipe jacking, micro-tunnelling, ground support, ranging from rock and directional drilling. bolts to ring beams and mesh. “Our team encountered a coal seam, gasses in the tunnel, two large water Please contact Haeny Inc. inrushes, three fault zones up to 103 +1 (205) 201 5505 m (337 ft) long, 11 karst cavities, [email protected] and more. In order to solve the Haeny Inc. | www.haeny-inc.com (Continued on page 18)

14 maY 2020 Tunneling & Underground Construction ® tuc& NEWSNEWSNEWS Ottawa tunnel: Ontario government calls for RFQs for Scarborough and Eglinton projects (Continued from page 10) The Scarborough Subway The extension will run underground, Extension is a nearly 8-km (5- westward from Scarlett Road to To expedite work on these projects, mile) extension of TTC’s Line 2 Renforth Drive. Through future tunneling will begin first, to be (Bloor-Danforth), from the existing phases of this project, the province followed by separate contracts for Kennedy Station northeast to is committed to establishing the balance of the work on each McCowan Road/Sheppard Avenue, connectivity with Pearson project. with an expected service date by International Airport. Moving forward with tunneling 2029-30. Companies interested in bidding on Scarborough and Eglinton West The Eglinton Crosstown on these tunneling contracts must marks significant progress for the West Extension is a 9.2-km (5.7- register with www.merx.com to province’s plan to build a world-class mile) extension of the Eglinton download the respective RFQs. IO transportation network where new Crosstown LRT (future TTC Line and Metrolinx will evaluate RFQ transit is built faster and at a lower 5) from the future Mount Dennis submissions and shortlist teams to be cost, getting people where they want station to Renforth Drive, with an invited to respond to a request for to go when they want to get there. expected service date by 2030-31. proposals in summer 2020. n

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Tunneling & Underground Construction maY 2020 15 ® tuc& NEWSNEWSNEWS DC Water: Environmental approval paves the way for CSO tunnel (Continued from page 11) dramatically improve the health of the river and the quality of life construction of diversion facilities for those who enjoy it. Cleaner and other supporting infrastructure rivers invite more recreation and to intercept (combined sewer entertainment as well as economic We start from your sketch, to 3D concept... overflows) from the existing vitality.” combined sewer system and divert The project will take place them to the tunnel when existing primarily on National Park sewer system capacity is exceeded Service land in northwest DC. during storms. Once diverted to the The environmental assessment tunnel, excess flows will be carried conducted by NPS found there by gravity to DC Water’s Blue Plains would be no significant impact on Advanced Wastewater Treatment the surrounding area. Plant,” the National Park Service “Clean water is vital to plants, said in a release. animals, parks and people who live, “We have seen the Anacostia work and play nearby,” acting NPS ...to fabrica�on, delivery & commissioning. River Tunnel, with its tremendous National Capital Area director Lisa performance, bring a resurgence to Mendelson-Ielmini said. “After that river and its banks,” said DC seeing the remarkable early success Water chief executive officer and of the tunnel on the Anacostia general manager David L. Gadis. River, it’s exciting for us in the “We know that the projects we National Park Service to think about have planned for the Potomac will the possibilities for the Potomac.” n Great Lakes: Project still faces stiff oposition

(Continued from page 9) had failed to seek authorization for Ontario. A roughly 6.4-km (4-mile) the project through the Great Lakes segment divides into two pipes that Submerged Lands Act as required KelleyEngineered Equipment, LLC run beneath the Straits of Mackinac. under a common-law doctrine that Environmental groups want the holds navigable waters and soils line decommissioned, contending beneath them in trust for public uses. Your turn-key design-build provider of the underwater pipes are aging and Bypassing those laws is “one custom mechanical equipment. Founded in vulnerable to a rupture that could of the most egregious attacks on 2007 by Brian & Cindy Kelley now with a do catastrophic damage to the citizens’ rights and sovereign public growing staff of 23, with 4 professional trust interest in the Great Lakes in engineers licensed in 9 states. Specializing lakes and their shorelines. Enbridge in below-the-hook li�ing systems, mucking says they’re in good condition and the history of the state of Michigan,” systems, gantries, pipe carriers, trailing gear, sustained only minor damage from a said Jim Olsen, the group’s president. custom tunneling shields, custom hydraulic tugboat anchor strike in 2018. Duffy said Enbridge will a�achments, conveyors, li� cars, equipment For Love of Water, an advocacy seek construction permits from modifica�ons, heavy load handling, custom group, urged the corridor authority the Michigan Department of cranes, personnel access systems, and to halt further work on the tunnel Environment, Great Lakes and more. This year Ma� Greger, Tim Lang, and plan. The Traverse City-based Energy and the U.S. Army Corps of Ma� Short joined KEE, bringing to the table organization argued that Enbridge Engineers. n a total of 45 years of experience at Robbins.

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16 maY 2020 Tunneling & Underground Construction UNDERGROUND CONSTRUCTION NEWSNEWSNEWSNEWSNEWS

INDUSTRY PROFILE Jacobs Associates involved in all aspects of underground construction rom a major mass transit proj- tunnels, respectively. The tunnels are excavation grouting ahead of the ect in San Juan Puerto Rico to 5.7-m (19-ft) excavated and 3.7-m tunnel face is being conducted to Fquaint wine cave designs for (12-ft) inside diameter. protect the groundwater resources developers and private owners in Making the project challenging under U.S. Forest Service land. California and an underground proj- was the fact that the tunnels pass Jacobs Associates provides wine ect that will add millions of gallons of through granite, gneiss and marble cave design services for developers, want to Southern California’s water rock formations. private owners and wine cave con- supply, Jacobs Associates is involved Ground conditions in the tunnels tractors. With more than 20 years of in almost all levels of underground range from massive, hard, strong and wine cave design experience and 50 construction and tunneling. abrasive rock to very blocky and years of tunneling experience, the In 1954 Donavan Jacobs estab- seamy rock and crushed ground. Ad- company is able to provide creative, lished the business as a one-person ditionally, the tunnel alignments cross functional designs that meet the consulting firm. He took his first active splays of the San Andreas Fault varying code standards throughout assignment in this role as project in three locations. California’s counties. engineer for a consortium of Kaiser- Control of ground water inflows While much® of the work Jacobs Walsh-Perini-Raymond on a suc- is critical in order to avoid impacts to Associatestuc& does is in California, the cessful contract bid for the Snowy the San Bernardino NationalNEWS Forest firmNEWS is not limited.NEWS One of it biggest Mountain hydro electric tunnel proj- and San Manwel Indian Reserva- current projects is the Rio Piedra ect in New South Wales, Australia. tion. ITA issues call forContract 2020 awardin San Juan nominations Puerto Rico. More than 50 years later, Jacobs The tunnel lininghe International for the Tunnelling Arrow -Harvey Parker,This center, wasjob given consists the Lifetime A chievementof a 1,500-m award in 2019. Associates is one of the most suc- head Tunnels is designedAssociation has to issued withstand a (4,921-ft) long underground rapid Tcall for nominations for the 6th edition of the International cessful contractors in America. The an earthquakeTunnelling of magnitude and Underground Space8.0. In transit guideway with two under- company was ranked ninth among addition, one Awards.portion The awards of ceremony the align- ground subway stations. location and date will be announced all contractors by Engineering News- ment crosses atan a later active date, but itsplay will be near of the the Most of the project structures end of the calendar year. Record in 2006. San Andreas Fault,The sixth where edition of the a awards special are located below the groundwater will include some notable changes. Jacobs Associates currently has lining sectionThis was year, theused ITA-AITES to Awardsaccom - table and many of the tunnels pass has introduced two new categories. seven offices and numerous projects modate faultThe rupture. first is the “Overcoming A primary the beneath occupied historical build- Challenge” award for projects in the works. lining of boltedthat and dealt with gasketed either foreseen precast or ings with less than 5 m (16 ft) of One of the largest current projects concrete segmentsunforeseen was extreme designed challenges to cover. during excavation and construction. for Jacobs Associates is in San Ber- withstand a pressureThe second new of category 274 is namedm (900 • MajorA Project unique of the Year —aspect Entries of this can be submittedproject through “Oddities of the Underground,” over €500 million. a dedicated website: https://awards. nardino and Riverside counties, CA. ft) of hydrostaticcelebrating head the creativity, — the ingenuity highest • isProject that of the different Year — tunnelingita-aites.org/entries. methods and imagination of the human spirit between €50 million and €500 Nominations for the different That is where Jacobs is working on pressure everin considered its endeavors underground. in design weremillion. used alongcategories the mustalignment, be related to projects The ITA 2020 Awards continue • Project of the Year incl. for which the major civil engineering the Inland Feeder’s 72-km (45-mile) of a segmentalthe successtunnel of the firstlining. five editions Two of whichRenovation yielded— up to €50 manywork waslessons completed onbetween the Jan. 1, alignment of large-diameter tunnels closed-face tunnelthe ITA Tunnelling boring and Undergroundmachines impactmillion. of these 2018methods and April 1, 2020. on the Space awards in Switzerland, • Technical Innovation of the The Young Tunneller of the Year and pipelines that will extend from designed to withstandSingapore, France, a pressure China and in of 91 structuresYear. above. ■rewards an individual born after Miami, FL in 2019. • Overcoming the Challenge. Jan. 1, 1986 and who has brought an the foothills of the San Bernardino m (300 ft) of This year the entries can be • Oddities of the Underground. outstanding contribution to n Mountains to the Colorado River hydrostatic submitted in seven categories: • Young Tunneller of the Year. tunneling. Aqueduct in Riverside County, CA. load were The project will nearly double used to ex- DAVIDDAVID R.R. KLUGKLUG && ASSOCIATES,ASSOCIATES, INC.INC. the delivery capability of the Metro- cavate the politan Water District of Southern Arrowhead California’s (MWD) from the east Tunnels. In SpecialtySpecialty Products Marketing and Services Services to for the the branch of the State Water Project. combina- North NorthAmerican American Tunneling Tunneling and Mining Industry Industries It is expected to be able to provide tion with the southern Californians with as much watertight David R. Klug - President as 2.46 GL/d (650 million gal/d) of primary and www.drklug.com Two Penn Center West, Suite 122 Tel (412) 787-2255 additional water. final linings, 6000 Waterdam Plaza Dr., Ste. 120 Tel (724) 942-4670 Pittsburgh, Pennsylvania 15276-0102 Fax (412) 787-5267 The project is comprised of the extensive McMurray, Pennsylvania 15317 Fax (724) 942-4671 East and West contracts that are probe-drill- Email: [email protected] Cell (412) 670-0263 9.6 km (6 miles) and 8 km (5 miles) ing and pre-

Tunneling & Underground Construction maY 2020 17

T&UC MARCH 2007 11

MIN_088_091.indd 4 2/27/07 3:36:05 PM ® tuc& NEWSNEWSNEWS Robbins: More than 29 km of tunnels will comprise North Line project waves — is being used to detect (Continued from page 14) delivered: the after-sales phase was not the end of service, but the changing conditions ahead of the ground problems, there were more beginning of site service,” said Jin. TBM. The method can predict the than 160 special technical research While the completion of the distribution and scale of joints and meetings held,” said Jin. first tunnel — the longest single- fissures, allowing the crew to plan Throughout tunneling, the heading construction on record ahead. contractor expressed thanks for water tunnels in Guangxi — is Located near Laibin City, for Robbins Field Service staff. a milestone, there is more to do. the North Line project provides “Robbins personnel provided good The Robbins machine will be much-needed drought relief using technical support from equipment inspected and relaunched to bore a a network of tunnels totaling installation and commissioning second tunnel 4.2 km (2.6 miles) in 29.4 km (18.3 miles). “This tunnel through to tunnel completion. length. The ground conditions are will realize the dream of drought After the equipment was handed predicted to be equally challenging, control that people in Central over to our company, they still but the tunneling operation has Guangxi have had for many years. helped us with equipment usage some help from ground prediction The breakthrough is the most on our project, which makes us methodology. Tunnel Reflection important milestone event in very satisfied with the Robbins Tomography — consisting of this first phase of the North Line after-sales service. Robbins really ground prediction using seismic project,” said Jin.n

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18 maY 2020 Tunneling & Underground Construction ® tuc& NEWSNEWSNEWS

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Tunneling & Underground Construction maY 2020 19 ® tuc& UCA of SME News UCA presents 2020 awards

Lifetime Achievement Award to John J. Reilly, Henry A. Russell Jr. and George E. Williamson

he Lifetime Achievement Reilly is a graduate of the Uni- rehabilitation in the Tunnel Engineer- Award recognizes outstand- versity of Sydney (B.E. honors civil) ing Handbook, TCRP Synthesis 23, Ting achievements in the un- and the University of California and Federal Highway Administration derground design and construction Berkeley (M.S. structures). He was manuals. He is also a member of The industry. These outstanding achieve- president of the American Under- Moles and the Transportation Re- ments have been accomplished ground Construction Association search Board. through the design or construction from 1999 to 2001 and chair of two Since joining Traylor Bros., Inc. in of civil underground facilities, and International Tunneling Association 1985 as vice president of the Under- the winners have contributed sig- committees. ground Division, nificantly to the education, planning, Henry A. Russell Jr., PE, PG, has George William- design, construction or rehabilitation more than 50 years of international son has procured of tunnels and underground facilities. tunnel experience. He worked for and supervised This includes seeking advances in Parsons Brinckerhoff for 40 years, be- the successful new methods and materials and ad- coming the national program leader construction of vancing the public understanding and for tunnel rehabilitation and senior dozens of tun- concurrence with the beneficial uses vice president. He currently works for nel contracts. He of underground space. Mott MacDonald as a principal tun- received the 1999 John J. Reilly, P.E., C.P.Eng., nel engineer and williamson Golden Beaver has more than 56 years of experi- vice president. He Award for supervision, which recog- ence in the management, design has written more nizes the top tunnel engineers and and construction of large, complex than 40 technical managers in North America. In his infrastructure and underground proj- papers on tun- time with Traylor, he led the acquisi- ects in the United States, Australia, nel inspection, tion and construction of more than 40 Canada, United Kingdom, Europe, security, structural underground projects throughout the South America repairs and fire- United States. This includes multiple and the Middle russell proofing. Since award-winning projects, such as the East. In 1987, he 1997, he has been St. Clair Tunnel, the South Bay Ocean established a con- an official delegate to the Interna- Outfall, the Los Angeles Eastside sulting practice in tional Tunneling Association (ITA), Light Rail Transportation Project and the areas of man- Working Group 6-Repair and Main- the Queens Bored Tunnels. agement, design, tenance of Tunnels, where he served In addition to being director of construction, con- as vice chair and chair. During this special projects for Traylor’s Un- tracting methods, period, the Working Group produced derground Division, Williamson sits partnering, risk three documents on tunnel refurbish- on the board of directors and the reilly management and ment and tunnel fireproofing. management committees that direct risk-based cost Russell has been a member of the strategic planning for the entire com- estimating. He has written more than UCA Fox Committee since 2000, a pany. He is a member of the Ameri- 100 papers in these areas, has chaired member of the American Society of can Society of Civil Engineers, The numerous expert panels for metro Civil Engineers (ASCE) Tunnel Task Moles and a registered professional systems, tunnels, highways and bridg- force since 2015 and a keynote speak- engineer in 10 states and the District es, and has served on several national er at numerous conferences. His pub- of Columbia. He is a graduate of the academy panels. lications include chapters on tunnel University of California Berkeley.

Outstanding Individual Award to Gary A. Almeraris he Outstanding Individual ground construction and to the Un- blaster and an engineering gradu- Award recognizes those indi- derground Construction Association. ate of the City College of New York Tviduals, including contractors, Gary Almeraris has been in- with a masters in management from engineers, owners and suppliers who volved in the underground indus- Worcester Polytechnic Institute. have made significant contributions try for more than 40 years. He is a He is currently vice president of to the field of tunneling and under- licensed professional engineer, a operations for Skanska USA Civil

Tunneling & Underground Construction May 2020 55 ® tuc& UCA of SME News

Northeast and is transit, water supply, water power, boring machines. Additionally, he its leading under- combined sewer overflow (CSO) has managed many varied support- ground expert. and highways, most of which include of-excavation projects, including a He has worked major underground work. number of frozen ground solidifica- primarily on the Almeraris has managed the con- tions. Some of his more challenging northeast coast struction of several SEM caverns, projects have included the Big Dig, and occasion- utility infested cut-and-covers, and the Second Ave Subway, DC Water’s ally oversees large tunnels in rock, soil and mixed face CSO program and the Fulton St./ almeraris projects including driven by conventional or tunnel- WTC transit hubs.

Outstanding Educator Award to James W. Mahar he Outstanding Educator visiting assistant ings. Mahar has been a thesis adviser Award is presented by the professor in the to 12 graduate students, and two of TUCA Executive Commit- Department of the dissertations have been on com- tee to professors and teachers who Civil Engineering puter simulation of loosening loads have had an exceptional career in at the University in rock tunnels and on prediction of academia and education in the areas of Illinois, Cham- squeezing behavior in fault zones and of underground design and construc- paign-Urbana. soft ground tunnels. He has received tion. These individuals have also Since 2003, he three teaching/mentoring awards and made significant contributions to has been a senior the 2010 professional achievement the industry through their academic mahar lecturer in the award. interests, as well as through the intro- departments of Mahar has more than 47 years of duction of many student graduates Civil Engineering and Geosciences at consulting experience in design and into the industry. They are nominated his undergraduate alma mater, Idaho construction on more than 200 proj- by their peers. State University. In his engineering ects involving underground openings James W. Mahar has more than 21 geology, geologic data methods, proj- in soil or rock. He received his Ph.D. years as an educator in engineering ect management and case histories from the University of Illinois in geology and geotechnical engineer- courses, he focuses on design and geology with an engineering geology ing. From 1975 to 1980, he was a construction of underground open- and rock/soil mechanics specialty.

Project of the Year Award to Regional Connector Transit Project, Los Angeles, CA, — a joint venture of Skanska and Traylor, WAP, Mott McDonald, Arcadis, EPC Consultants and the LACMTA he Project of the Year Award matic earth pressure balance (EPB) tion contract as a change order at the recognizes an individual or a conditioning, monitoring, tie-back outset of the project. A single TBM Tgroup that has shown insight removal shaft and adit, cross passage was used to bore both tunnel drives. and understanding of underground support and underpinning. It was rebuilt by Herrenknecht (for construction in a significant project, The 3-k (1.9-mile) underground its third journey) and modified to which may include a practice, develop- light rail project extends from the Los navigate the extremely tight radius ing concepts, theories or technologies Angeles County Metropolitan Trans- curves along the alignment. Traylor to overcome unusual problems within portation Authority’s (LACMTA) fabricated the precast concrete tun- a project. Gold Line Little Tokyo/Arts District nel segments. Each of the twin tunnel The Regional Connector Project Station to the 7th Street/Metro Cen- launches was extremely challenging was unique in that it required a va- ter Station through downtown Los as the TBM mined through sandy riety of structures and construction Angeles. The project includes 2,880 m materials with low cover 4.5 m (15 ft) techniques, including TBM tunneling, (9,450 ft) of 5.7-m (18 ft, 10-in.) twin- underneath existing structures. Per- deep cut-and-cover excavation, large bored tunnels and three underground meation grouting and compensation cavern sequential excavation method stations. The project connects to exist- grouting were installed as a precau- and underpinning in a dense urban ing lines and stations at both ends of tion. The owner/contractor team add- environment adjacent to and/or un- the new track. The entire alignment is ed a horizontal inclinometer (shape derneath numerous iconic and his- within potentially gassy ground con- array) above each of the tunnel drives toric buildings. Innovative solutions ditions under downtown Los Angeles. that provided settlement information were considered and implemented The joint venture took over the 1.5 m (5 ft) above the TBM in real- across the project, from semi-auto- in-progress advanced utility reloca- (Continued on page 57)

56 may 2020 Tunneling & Underground Construction ® tuc& UCA of SME News Women in Tunneling observe Women in Construction Week n celebration of Women development and use of in Construction Week, underground space. Joining IUCA of SME’s Women in with UCA has enabled both Tunneling (WIT) group held organizations to expand and its first tunnel tour on Feb. 15, grow their international vis- 2020. Atkinson Construction ibility, career opportunities hosted the group at its proj- and professional develop- ect in San Antonio, TX. The ment. project includes the construc- As the number of wom- tion of three tunnel drives, en establishing careers in one open cut and five shafts the underground design and for the installation of 3,216 m construction industry grows, (10,550 ft) of 137-cm (54-in.) WIT focuses on providing a welded-steel pipe. WIT tunnel tour attendees included (l-r) Zuzana Skovaj- network and a strong sup- Led by Atkinson’s field sova, COWI North America; Audrey Housson, Atkinson port association for women engineer, Audrey Housson, Construction; Lizan Gilbert, Atkinson Construction; to share experiences and and Lizan Gilbert, precon- Amanda Kerr, Michels Corp; Ashley Heckman, Aldea Ser- offer mentorship in the un- vices; Emily Haddad, Atkinson Construction and Gabri- struction executive, the tour elle Ferro, Atkinson Construction. derground industry. If you included a full walk through are interested in hosting the TBM tunnel, observation of pipe WIT was founded in 2012 as a or being part of a future tour with installation and a visit to the complet- support association for women in tun- WIT, contact Emily Haddad at emily. ed 152-m (500-ft) hand mine tunnel. neling to network with like-minded [email protected] or Lizan Gilbert In addition, the group met key proj- professionals. In 2019, WIT became at [email protected] for more ect personnel and discussed possible an affiliate of the UCA Divison SME. information. Or visit the SME/UCA locations and dates for future WIT The mission of the UCA Division Community at http://tiny.cc/smecom- tunneling tours. is to promote the wise and effective munity-WIT. n UCA Young Members enhance the visibility of the underground industry oin the UCA Young Members ing technical skills to use in the field, webinars and become a member of (UCAYM) group in support of and sharing innovative technologies the SME community group (UCA Jthe growth and development of and research with the membership. Young Members) to keep up-to-date young engineers and professionals The group consists of people of on university outreach, social events in the tunneling and underground all ages and backgrounds who believe and discussions. construction industry. UCA Young the stability of the industry depends More information can be found at Members are interested in learning on the next generation of profes- http://community.smenet.org/ucaym/ more about the profession, develop- sionals. Join them for free monthly home. n

Project of the Year (Continued from page 56) tiebacks that damaged the equipment. ern at a shallow depth in soft rock, To recover from the delay, a third beneath existing building foundations time during mining. Using tight EPB mining shift was added to the second and major utilities and using the se- PLC controls and extensive instru- drive. The tunnel crews set multiple quential excavation method was one mentation data, the team was able to records for L.A. Metro, including best of the most challenging parts of the keep the settlement under 0.2 percent single day production at 58 m (190 project. Extensive design modeling, volume loss and remain below the ft), and the project gained back two sensitivity analysis and daily review of contractual settlement limits. months on the schedule. field data led to the successful excava- While tunneling the first drive, Excavating the 91-m long, 17.7- tion and support of the cavern two the TBM encountered unexpected m wide, 11-m high (300-ft long, 58-ft months ahead of schedule and within obstructions, two steel piles and 48 wide, 36-ft high) track crossover cav- the acceptable building settlements.n

Tunneling & Underground Construction May 2020 57 ® tuc& UCA of SME News Scholarships and awards available from UCA of SME he Underground Construction management. Applicants must have amount of the award, approximately Association of SME Scholar- a demonstrated interest in the under- $5,000, is apportioned to one or more Tship was established to encour- ground industry. Up to 12 recipients students at the discretion of the RETC age undergraduate and graduate can be selected. Each recipient will Executive Committee. Scholarship academic careers in the field of tun- receive: recipients also receive RETC atten- neling and underground construction dance awards as described previously. • RETC or NAT Conference and associated disciplines involved in registration. the development and construction of UCA Young Members Scholarship • Round-trip airfare to the underground infrastructure. The UCA UCA of SME Young Members conference. of SME annually awards one or more Scholarship for NAT/RETC atten- • Hotel accommodations at the scholarships to promising college dance provides selected students with conference hotel. students who desire to develop their an opportunity to attend conferences • Conference proceedings. skills in tunneling and underground at which they can experience the chal- • Social function tickets. construction. lenges, opportunities and rewards of • A $200 stipend for a career in the field of tunneling and miscellaneous cash needs. RETC Attendance Award underground construction. The goals The Rapid Excavation & Tunnel- Recipients are responsible for of the award are to increase exposure ing Conference (RETC) Attendance their own ground transportation and to career opportunities and to provide Award provides students with an for other expenses, including meals, educational and networking opportu- opportunity to attend the RETC or other than at social functions. nities to future underground industry the North American Tunneling Con- professionals. ference. Applicants must be full-time RETC Executive Committee Visit https://www.smenet.org/uca- freshman, sophomore, junior, senior Scholarship of-sme/membership/scholarships for or graduate students with a desig- RETC annually awards one or more information on these awards, nated major in an applicable field of more scholarships to college students including criteria and deadlines for engineering (civil, mechanical, mining, who desire to develop their skills application and instructions on how to electrical, geological) or construction in the tunneling industry. The total apply. n Personal News Brokk unveils dust supression system JUSTIN AKKERMAN (UCA/SME) o combat harmful silica dust rather than forming puddles, for a has been promoted to president of and other airborne particles, safer, cleaner jobsite. Available for Akkerman Inc., a TBrokk’s new Atomized Water all Brokk remote-controlled demo- trenchless under- Mist System produces an atomized lition robots, the Atomized Water ground construc- fog that effectively binds dust par- Mist System offers an ideal solution tion equipment ticles in the air while also providing to mitigate hazardous silica dust. manufacturer in ground-level dust suppression. Health and safety organizations Brownsdale, MN. Additionally, the mist dissipates, have identified silica dust as a signif- He entered the icant hazard and have enacted family business in regulations that limit the per- Akkerman 2014 as operations missible exposure for workers. manager. He has Some contractors choose to use been responsible for corporate admin- spray systems, but water drop- istration, directing the management lets are much larger than silica team, and managing the production dust. Since silica particles are and inventory control departments. more likely to bond with water Akkerman launched its ISO 9001:2015 droplets of similar size, Brokk quality management system and engineered the dust suppression acquired several state-of-the-art ma- system to produce 10-micron chining centers resulting in produc- mist droplets. This creates a fog tion efficiencies. Previous president of atomized water that captures MAYNARD AKKERMAN (UCA/ The Atomized Water Mist System requires dust particles in the air and SME) will continue as chief executive less water than other methods, just 0.2 L/ spreads along the ground for officer and chairman of the board. n min (6.76 oz per minute). optimal dust suppression. n 58 may 2020 Tunneling & Underground Construction CALL for TOPICS Contract Practices Design Design/Build Projects Diffi cult Ground Drill and Blast Environment, Health and Safety PAPERS Future Projects Geotechnical Considerations Ground Control, Face Support and Monitoring Ground Support and Final Lining Grouting and Ground Modifi cation Hard Rock TBMs Impacts of COVID-19 on the Tunneling Industry Insurance International Projects Large Span Tunnels and Caverns Microtunneling and Trenchless Tunneling New and Innovative Technologies Pressure Face TBM Case Histories Pressure Face TBM Technology Project Planning Risk Management The Rapid Excavation and Tunneling Conference (RETC) is the SEM/NATM premier international forum for the exchange and dissemination Shafts and Mining of developments and advances in underground construction. Tunnel Rehabilitation RETC provides innovative solutions to the unique challenges Tunneling for Sustainability associated with the tunneling industry. Additional topics of interest will be considered. Submit abstracts online at: https://sme-retc.secure-platform.com/a Share your tunneling expertise at one of the leading conferences for underground construction. Deadline is June 30, 2020 Submit your 100-word abstract by June 30, 2020 Authors will be notifi ed of acceptance by September 2020. Final manuscripts from accepted authors are for consideration to due December 15, 2020. Manuscripts are mandatory https://sme-retc.secure-platform.com/a for inclusion and must be received on time. All man- uscripts will be included in the proceedings volume The ideal paper presents the solutions and outcomes distributed on-site to all full registrants. If you cannot to interesting or unique challenges. commit to completing a manuscript on time, please do not submit an abstract for consideration.

Society for Mining, Metallurgy & Exploration 12999 E. Adam Aircraft Cir. For more information, Englewood, CO USA 80112 contact: 800.763.3132 | 303.948.4200, www.smenet.org, [email protected] ® Tunnel Demand tuc& Forecast

Compiled by Jonathan Klug, David R. Klug & Associates

TUNNEL NAME OWNER LOCATION STATE TUNNEL LENGTH WIDTH BID USE (FEET) (FEET) YEAR STATUS Gateway Tunnel Amtrak Newark NJ Subway 14,600 24.5 2022 Awaiting funding 2nd Ave. Phase 2 NYC-MTA New York NY Subway 16,000 20 2021 Under design 2nd Ave. Phase 3-4 NYC-MTA New York NY Subway 89,600 20 2022-27 Under study Kensico-Eastview NYC-DEP New York NY Water 10,500 27 2024 Under study Connection Tunnel Flushing Bay CSO NYC_DEP New York NY CSO 13,200 20 2026 Under study Bay Park Conveyance NY DEC New York NY CSO 18,500 8 2020 RFQ Project submitted Cross Harbor Freight NYC Reg. Develop. New York NY Rail 25,000 30 2022 Under study Tunnel Authority Metro Tunnel Boston MRWA Boston MA Water 23,760 10 2027 Under study Program - Northern Metro Tunnel Boston MRWA Boston MA CSO 50,160 10 2028 Under study Program - Southern Silver Line Extension Boston Transit Boston MA Subway 8,400 22 2024 Under design Authority Narragansett Bay Narragansett Bay Providence RI CSO CSO Phase III - Commission Short list Pawtucket Tunnel 13,000 28 2020 Announced Conveyance Tunnel 8,800 10 2024 Under design Amtrak B&P Tunnel Amtrak Baltimore MD Rail 40,000 32 2021 Awaiting funding Hampton Roads Virginia DOT Hampton VA Highway 7,500 42 2019 Dragados JV Bridge-Tunnel Project Roads awarded Alex Renew Long- City of Alexendria Alexandria VA CSO 10,500 20 2019 Short list Term Control Plan announced Potomac River CSO DC Water and Sewer Washington DC CSO 24,000 18 2022 Under design Tunnel Authority Superconducting TNEM/BWRR Washington DC Rail 146,520 43 2021 Under design Maglev Project - Northeast Corridor Olentangy Relief City of Columbus Columbus OH Sewer 58,000 14 2019 Under design Sewer Tunnel Alum Creek Relief City of Columbus Columbus OH Sewer Tunnel Phase 1 30,000 18 2019 Under design Phase 2 21,000 14 2020 Under design Shoreline Storage NEORSD Cleveland OH CSO 16,100 21 2021 Under design Tunnel Shoreline NEORSD Cleveland OH CSO 11,700 9.5 2021 Under design Consolidation Tunnel Southerly Storage NEORSD Cleveland OH CSO 18,350 23 2024 Under design Tunnel

To have your major tunnel project added to the Tunnel Demand Forecast, or to update information on a listed project, please contact Jonathan Klug at [email protected].

60 may 2020 Tunneling & Underground Construction ® Tunnel Demand tuc& Forecast

TUNNEL LENGTH WIDTH BID TUNNEL NAME OWNER LOCATION STATE STATUS USE (FEET) (FEET) YEAR ALCOSAN CSO Allegheny Co. Pittsburgh PA CSO Ohio River Sanitary Authority 10,000 14 2022 Under design Allegheny River 41,700 14 2023 Under design Mononghahela River 53,900 14 2024 Under design Enbridge Line 5 Enbridge Traverse City MI Oil 23.760 12 2020 Contractor Tunnel selected I-70 Floyd Hill Colorado Dept. of Denver CO Highway 15,840 60 x 25 2022 Under design Highway Tunnel Transportation W-6: Highway 90 to San Antonio Water San Antanio TX Sewer 28,000 10 2020 Bid date May 1, SW Military Drive Systems 2020 D2 Subway - 2nd Dallas Area Rapid Dallas TX Highway 3,000 22 2020 Under design Light Rail Alignment Transit Ship Canal Water Seattle Public Seattle WA CSO 14,250 19 2018 Lane/Salini Quality Project Utilities awarded West Seattle to Sound Transit Seattle WA Transit 10,500 18 2022 Under design Ballard Extension LA Metro Speulvada Los Angeles MTA Los Angeles CA High/Trans. 55,500 60 2020 Shortlist Pass Corridor announced Folsom Area Storm SFPUC San Francisco CA CSO 4,000 12 2022 Under design Water Improvement BART Silicon Valley Santa Clara Valley San Jose CA Subway 26,400 56 2021 Single tunnel Phase 2 Tunnel Transit Authority option approved California Waterfix 1 Delta Conveyance Sacramento CA Water 39,905 28 2020 Delayed California Waterfix 2 Design and Const. 403,400 40 2020 Delayed Newell Creek Dam City of Santa Cruz Santa Cruz CA Water 1,500 14 2020 Obayashi awarded Ashbridges Bay Outfall Metrolinx City of ON CSO 11,500 23 2018 Southland/Astaldi Tunnel Toronto JV Awarded Yonge St. Extension Toronto Transit Toronto ON Subway 15,000 18 2016 Under study Massey Tunnel City of Toronto Toronto ON CSO 20,000 18 2018 Under design Inner Harbour West City of Toronto Toronto ON CSO 18,400 19 2021 Under design Scarborough Rapid Toronto Transit Toronto ON Subway 25,000 18 2018 RFQ due April 15, Transit Extension Commission 2020 Elington Crosstown Toronto Transit Toronto ON Subway 40,000 18 2020 RFQ due May 29, West Extension Commission 2020 Green Line LRT City of Calgary Calgary AB Transit 26,250 20 2018 RFQ submitted Second Narrows Tunnel City of Vancouver Vancouver BC CSO 3,600 14 2013 Traylor/Aecon JV awarded Annacis Island Outfall City of Vancouver Vancouver BC Water 8,000 10 2017 Pomerleau/Bessac Awarded Millennium Line Metro Vancouver Vancouver BC Subway 18,700 18 2020 Short list Broadway Extenstion announced Eagle Mt. Pipeline Fortic BC Woodfibre Vancouver BC Oil 29,500 13 2020 Short list announced

Northern Gateway Enbridge Northern Kitimat BC Oil 23,000 20 2014 Under design Hoult Tunnel

Tunneling & Underground Construction may 2020 61 Expand your KNOWLEDGE Dive into a tailored, single-track program of subject- specific presentations that focus on innovation and practical experience. Network and CONNECT Energize friendships with longtime colleagues, forge Make Plans new connections, and exchange ideas with fellow industry leaders from around the world. Learn from INDUSTRY LEADERS Leading international tunneling companies attend to Attend Cutting Edge, sharing the latest in technology, November 9 - 11, 2020 innovations and safety. Explore Advances in TUNNELING in Dallas, Texas TECHNOLOGY Participate in our off-site field trip and technical tour at the Mill Creek Drainage Relief Tunnel excavated ucaofsmecuttingedge.com by The Robbins Company. Photo © The Robbins Company, Mill Creek SAVE 25% WITH NEW BUNDLE PRICING IN THE SME STORE ENHANCE YOUR PROFESSIONAL LIBRARY with special bundle pricing on select popular titles

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