Dubna Site Investigation
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Dubna Site Investigation Initiated by JINR and supported by GDE An Evaluation of a Proposed Site for the International Linear Collider near Dubna, Moscow Region, Russia International Linear Collider Global Design Effort Joint Institute for Nuclear Research 18th November 2010 Authors JINR, Dubna, Russia Yulian Budagov Yury Denisov Andrey Dudarev Grigory Shirkov Grigori Trubnikov GSPI, Moscow, Russia Valery Sokolov Vasiliy Kozhanov Fermilab, Batavia, USA Victor Kuchler Tom Lackowski Marc Ross Hansen Engineering, Springfield, USA Tracy Lundin DESY, Hamburg, Germany Wilhelm Bialowons Nicholas Walker ILC Report No. ILC-REPORT-2010-26 ILC-HiGrade Report No. ILC-HiGrade-2010-008-1 ILC-EDMS Document ID D*928865 ISBN: 978-5-9530-0265-3 Table of Contents 1 Executive Summary/Overview of the Site ....................................................................... 3 1.1 Introduction .............................................................................................................................. 3 1.2 ILC Tunnel Configurations studied by the GDE ......................................................................... 4 1.3 The Dubna Site.......................................................................................................................... 5 2 Description of Current Dubna Site Design ....................................................................... 8 2.1 Preliminary Design (Shallow Bored Tunnel with Surface Level Gallery) .................................. 8 2.2 Verification of GSPI Soil Boring Report ..................................................................................... 9 2.3 Status of Cost Estimating Effort .............................................................................................. 10 3 GSPI Soil Boring Report ........................................................................................................ 13 3.1 Results from the Soil Boring Report ....................................................................................... 14 4 Near Term Topics for Further Investigation ................................................................ 17 5 Summary ................................................................................................................................... 18 6 References................................................................................................................................. 18 2 1 Executive Summary/Overview of the Site 1.1 Introduction In this Report we describe a study to consider siting the International Linear Collider (ILC) near Dubna, Russia, in the northern part of the Moscow region, initiated by the Joint Institute of Nuclear Research, (JINR, Dubna). This site (referred to as the ‘Dubna Site’) is well suited for the ILC because it: is located near JINR; has excellent geological conditions which would allow the collider to be constructed near the surface; is lightly populated; has well developed utilities infrastructure. The study reported here was intended to evaluate and describe the geotechnical aspects of the Dubna Site. It was proposed by JINR during the development of the ILC Reference Design in 2006, and the work in this Report was subsequently carried out by the State Specialized Project Institute (GSPI) part of ROSATOM, in 2008 [1]. The Dubna Site geotechnical study was done as part of the ILC Global Design Effort (GDE) Technical Design Phase. The GDE will use these results in three ways: • The geotechnical details from the GSPI report will enable a preliminary analysis of a shallow site for ILC. Two specific shallow sites have been studied, the Dubna site and a site near DESY, in northern Germany, referred to as the ‘DESY site’ [2]. • The process of optimizing the site alignment, based on constraints identified in the proposed Dubna site, is instructive and we expect to be able to use this process as a model for the evaluation and alignment optimization of other potential sites. • The site evaluation and analysis process, whereby site-specific geotechnical, topographical, cultural and infrastructure considerations are taken together as a model is also quite instructive. During the preparation of the ILC Reference Design, as reported in the Reference Design Report (RDR) [2], the GDE limited its attention to deep-rock sites. These involve a very different set of design criteria which, without extensive and costly deep-borehole studies, will not be understood in the same manner as a shallow site. As a result, the RDR sample site development was based on idealized conditions including, for example, parametric cost estimation based on projects done in similar conditions. In contrast, the study reported here includes specific alignment information and geologic borehole sample data. In the RDR, two near surface European sites where mentioned (RDR pages 18 – 19): “A second European sample site near DESY, Hamburg, Germany, has also been developed. This site is significantly different from the three reported sites, both in geology and depth (25 m deep), and requires further study. In addition, the Joint Institute for Nuclear Research has submitted a proposal to site the ILC in the neighborhood of Dubna, Russian Federation.” and 3 “The DESY and Dubna sites are examples of ‘shallow’ sites. A more complete study of shallow sites – shallow tunnel or cut-and-cover – will be made in the future as part of the Engineering Design phase.” This document includes an overview of the Dubna site, including a conceptual layout of the ILC tunnels for the site, an analysis and review of the State Specialized Project Institute (GSPI) Dubna Geotechnical Site Study, initiated by JINR, and a short, parametric evaluation of potential cost savings for the site. For the latter, since the Site Study does not include construction cost information, results from a recent Illinois, (flat topography), US-based main linac tunnel configuration cost study were adjusted to fit the surface features of the Dubna site. The cost savings evaluation indicates the importance of surface feature intersections for shallow site configurations. It is well known that such features, and the actual flatness of the topography, are cost – drivers for near surface, excavation-type construction. For the relatively uninhabited Dubna site, a number of road crossings and a railroad crossing would have to be modified to allow passage of the ILC. Including these, as was done for the Illinois tunnel study, effectively counteracts the anticipated cost savings. By ignoring the surface features, and assuming a very flat topography, one is able to see what basic near-surface construction costs might be. 1.2 ILC Tunnel Configurations studied by the GDE The general Conventional Facilities layout of the ILC is described as follows: • Underground tunnels, about 31 km long, house the main accelerators and the Beam Delivery Systems (Beam Tunnel), and their associated support hardware. • Shafts or access tunnels along the length of the machine provide access to the above. In the RDR, they primarily support the large cryogenics plants at the surface required for the superconducting linacs. • A single collider hall at the Interaction Region (IR), large enough to support two physics detectors in a push-pull configuration. • A tunnel following a ‘racetrack’ shaped path located near the central IR region to house the electron and positron Damping Rings stacked above each other. • Several additional tunnels and service shafts house the electron and positron sources and injector linacs (injection into the Damping Ring), and connect the damping ring to the main accelerator housing. The GDE has evaluated eight different main linac tunnel configurations [4]: A twin deep tunnels with vertical access (RDR) B single deep tunnel with vertical access C twin near surface tunnels D single near surface tunnel with continuous buried surface service gallery E single near surface tunnel with surface support equipment buildings at 5 km F enclosure in open cut excavation with continuous surface service gallery G enclosure in open cut excavation with continuous buried service gallery H single tunnel enclosure in open cut excavation with surface support 4 Figure 1 shows the cross-sections of these tunnel configurations with a comparison matrix. The twin deep tunnel configuration (A) was chosen for all three sample sites in published in the RDR. (A possible further alternative for study during the Technical Design Phase (TDP) is the single deep tunnel variant B [3].) The remaining configurations (C-H) represent near-surface sites, of which the Dubna and DESY sites are examples. To properly assess these options and get a realistic comparison with deep rock tunnel options developed for the RDR requires a re-evaluation of design criteria [4]. By optimizing the design to best suit tunnels situated in soil, we can maximize potential cost savings. In urban areas like the DESY site, only tunnel construction with a tunnel boring machine and shafts spaced by relatively large distances is possible. Other underground elements like caverns or penetration shafts between two tunnels have to be avoided in any case. Making use of these simple rules could provide significant potential cost savings. The situation is at least partially different for the relatively rural Russian site at Dubna, described in this report. An open cut and surface gallery solution is possible at the Dubna site and making use of this advantage could result in additional potential cost savings. In section 2.3, such cost savings