Tunnelling and Underground Space Technology 76 (2018) 92–106

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Tunnelling and Underground Space Technology

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Development and applications of common utility in T ⁎ Tianyu Wang, Lixin Tan, Shaoyin Xie, Baosong Ma

College of Engineering, China University of Geosciences-Wuhan, No. 388 Lumo , Wuhan, Hubei Province, China

ARTICLE INFO ABSTRACT

Keywords: Common utility tunnels (utilidors) are attracting more and more attention in China with the rapid urban de- Utility velopment and growing need for public facilities. China is a large country with a huge north–south divide, which China leads to different situations of construction, types of utilities incorporated, route design and governance issues Latest status for utility tunnels in different cities. This paper introduces the latest status for such tunnels in China by collecting Future development and analyzing existing and planned utility tunnels in China from 1959 to 2020. Furthermore, the key issues that may influence the development of utility tunnels in the next decade in China are summarized. These, in com- bination with the domestic and foreign research status, suggest typical cases and a policy orientation which may be helpful to the future development of common utility tunnels in China and other countries.

1. Introduction pollution and transport problems (Laistner and Laistner, 2012). Since then, common utility tunnels have been widely used around the world The world-wide trend of increased urbanisation creates problems (Cano-Hurtado and Canto-Perello, 1999; Zhang, 2014). for expanding and newly-developing cities alike. The increasing popu- In , the government also developed utility tunnels as com- lation also leads to a great demand for reliable infrastructure, nowadays munal facilities. Initially, the city drainage system was constructed combined with a need for increased energy efficiency and a higher using tunneling. Then, different kinds of pipelines such as telecom, environmental awareness of the public. The use of underground space power cable, gas pipeline, etc. were incorporated in the underground can help cities meet these increased demands (Broere, 2016). Building tunnels which evolved into the use of utility tunnels in England (Zhang, underground utility tunnels to solve the problems has been im- 2014). For example, an arched was built in London in plemented in urban municipal services for about two centuries now 1861 (see Fig. 2). (Cano-Hurtado and Canto-Perello, 1999). From the combined water- In 1893, a 450-meter utility tunnel was built under Kaiser-Wilheim supply and sewer system left by the Roman Empire to the underground in Hamburg, Germany containing a heating pipe, water supply, lifelines in a metropolis such as Paris, , Madrid and Shanghai, the power cable, gas pipeline and telecom (see Fig. 3). Although problems system has been employed and improved to incorporate multiple utility appeared when the water supply pipe ruptured and there was a lack of pipelines and cables. The essence of this idea today is to build a man- space because of the bad design, the application of the utility tunnel accessible tunnel in the city underground space, which incorporates received a high evaluation. More than 15-km of utility tunnels were some or all of the electric power, telecommunication, gas, water supply built in Suhl and Halle before 1970, and the concept began to be pro- and other municipal cables and pipelines integrated with special moted all over Germany (Shun, 2008; Zhang, 2014). maintenance shafts and monitoring systems. Such tunnels also need to The research for common utility tunnels in America started in 1960 be carried out with unified planning, design and management to attain owing to the rapidly-growing cost of traditional buried construction sustainable development of urban underground space (Canto-Perello and the intrusion of overhead methods. Because of this, utility tunnels and Curiel-Esparza, 2001; Carmody and Sterling, 1993; Duffaut, 1996; were usually built in the center of cities and campus. Almost all kinds of Legrand et al., 2004). utilities except gas pipelines were incorporated in the utility tunnels Common utility tunnels originated from the urban utility systems of (Shun, 2008). Paris reformed by Haussman in 1855. As a great admirer of Roman Utility tunnel projects require better strategies and understanding at engineers, Haussman designed the Paris sewage system as a man-ac- an early stage in the city planning (Canto-Perello et al., 2016). The cessible tunnel and incorporated several water supply pipelines, com- Singapore government has evolved good strategies for its long term pressed air pipelines and sewage (see Fig. 1) to solve the water development as an island country with a strong imperative to convince

⁎ Corresponding author. E-mail addresses: [email protected] (T. Wang), [email protected] (L. Tan), [email protected] (S. Xie), [email protected] (B. Ma). https://doi.org/10.1016/j.tust.2018.03.006 Received 3 July 2017; Received in revised form 8 November 2017; Accepted 5 March 2018 0886-7798/ © 2018 Elsevier Ltd. All rights reserved. T. Wang et al. Tunnelling and Underground Space Technology 76 (2018) 92–106

Fig. 3. Utility tunnel built in 1893, Hamburg, Germany. Fig. 1. Common utility tunnel built in 1855, Paris.

Zhang, 2014). The development of utility tunnels in foreign countries has a history of more than 100 years old. Systematic research has been carried out with a variety of engineering practices. It leaded to the establishment of reasonable design, planning, financing and standard systems which has been worked out successfully in the mass construction of their own countries such as . At present, the research emphasis of utility tunnels in foreign countries is shifting from the planning and design to environmental protection technology and new construction methods (Xue et al., 2007.). The common utility tunnel, as well as the idea of a “Sponge City” (i.e. a city storm drainage system to reduce flooding and allow groundwater recharge) was introduced to the municipal construction field in China as a solution to encourage sustainable development in urbanizing areas. As the modern, prosperous society is expanding in China, the density of utility cable networks and pipelines has grown rapidly to meet the new demand. The resulting maze of utilities and other underground infrastructure has been termed “the spaghetti sub- Fig. 2. Utility tunnel built in 1861, London. surface problem” (Oude Luttikhuis, 1992). In concert with the rapid urban development, the open-cut (cut-and- cover) method of construction with its environmental and social cost the public that their decisions are made for the public good in the long- produced by repeated surface excavation is no longer acceptable for term. In the later 1990s, a large common utility tunnel was built for the city governors, and the traffic flow, safety and health have become new development area next to Marina Bay in Singapore. As the lifeline primary goals that cannot be ignored by civil engineers (Hunt et al., of the business and financial center in Marina Bay, the 3.9-km utility 2014). A consensus also has been achieved that a proper and long term tunnel was built 3 m deep with water supply, reclaimed water supply, underground space planning is critical to maintain the sustainable de- power cable, telecom, district cooling, garbage collecting and trans- velopment in cities (Besner, 2002; Hunt and Rogers, 2005; Pucker et al., porting system incorporated (Li and Mo, 2015). The whole under- 2006; Ma and Najafi, 2008). The definition of “sustainable develop- ground construction project cost about 0.52 billion U. S. dollars and it ment”, referring to the report Our Common Future submitted to the has anchored a major new development area for Singapore in a co- World Commission on Environment and Development, reads: “Sus- ordinated way. tainable development is development that meets the needs of the pre- Japan perhaps owns the most advanced technology and the most sent without compromising the ability of future generations to meet complete scheme and laws for utility tunnels in the world. The first their own needs” (Brundtland, 1987; Butlin, 1989). utility tunnel in Japan was built in 1926 in Chiyoda, Tokyo with power Utility tunnels have many benefits such as being environmentally cable, telecom, water supply and gas pipelines incorporated (see Fig. 4). friendly, providing long-term economic benefit and creating an efficient Utility tunnel construction in Japan had little further progress until the service capability. However, the high construction cost, technical dif- 1950–1960s. Then the Japanese government started to develop utility ficulties and other issues must also be considered (Canto-Perello and tunnels rapidly at the same time as its road construction program. The Curiel-Esparza. 2013). The main disadvantages are that the manage- utility tunnels law was set out in 1963. Up to now, there are more than ment of the common utility tunnels is not easy, and obtaining financing 2057 km of utility tunnels in more than 80 Japanese cities such as support for projects is often difficult. It was announced at the Fourth Tokyo, Osaka, Nagoya, etc. (Qian and Chen, 2007; Koyama, 2003;

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Fig. 4. Layout design of the utility tunnel in Chiyoda.

Session of the Congress of the People's Republic of China in the Report level of urban management and services such as in Wuhan (2009, on the Work of the Government that construction will begin on at least Wangjiadun district), (2004, Guangzhou higher education 2000 km of utility tunnels during 2016. The announcement is re- mega center), Xiamen (2010, the lake reservoir). The high development cognized as an overt policy support on the development and promotion period for utility tunnels began in 2013 when a 33-km utility tunnel of utility tunnels. (Song, 2016). was built in , Zhuhai because of the big service area, huge in- The purpose of this paper is to introduce the latest construction, vestment, special political significance, availability of advanced tech- research status for common utility tunnels and to discuss governance nologies, and encouraging policies (Zhang, 2016b). issues that will influence the development of such utility tunnels in the In recent years, the Chinese government has issued policies to the next decade in China. benefit of utility tunnel construction frequently. The Ministry of Finance of China decided to offer Earmarked Subsidy Funds to utility tunnel pilot cities for at least three years starting from January 13, 2. Overview on utility tunnel practices in China 2015. Three months later, the National Development and Reform Commission released the special bond issue guidelines for utility tunnel 2.1. Development of utility tunnels in Chinese urban areas construction in Chinese urban areas which also increases the opportu- nity for underground utility tunnel construction in China. Baotou, Since 1992, sustainable development is a basic national strategy Shenyang, Harbin, Suzhou, Xiamen, Shiyan, Changsha, Haikou, which has been set down in China. The concept of sustainable devel- Liupanshui, Baiyin and 10 other cities were identified as the pilot cities opment is very important when developing underground space (Zhang of for utility tunnel construction at the same time. At the beginning of and Wen, 2008). The situation is particularly severe in urban areas of 2016, the Prime Minister Li Keqiang said that utility tunnels can in- China such as Shanghai and Beijing where the use of underground space crease the overall carrying capacity of cities and raise the level of urban for utilities is by far the most extensive use of urban subsurface (Yu and management and services, and that this year more than 2000 km of Shi, 2006; Wang, et al., 2008). Underground space is being used to utility tunnels should be built (Song, 2016). Also, in 2016, another 15 serve a variety of functions, including underground commercial centers, cities were settled on as the second-period pilot cities for utility tunnel metros and different kinds of pipelines which may include water construction. Differ from the development in foreign countries, devel- supply-drainage pipelines, gas pipelines, cable ducts, and heating/ opment of utility tunnels in China is starting from few cities with great cooling pipes among others. This situation leads to the overlapping of demands and pilots cities with the local features to the whole country the underground utilities, and the problem becomes even worse when because of the growth in demand, regional difference and inequality new pipelines are being built through the network of the old pipelines development. A comprehensive system with local special features and (Curiel-Esparza and Canto-Perello, 2013). Therefore, common utility fits China's actual conditions is needed to guide the overall construction tunnels are needed to solve this problem, and make the underground of utility tunnels in China in the future. In general, the utility tunnel in space of Chinese urban areas normative, safe, fully utilized and sus- China is still in the experimental construction phase, which is shown by tainable. the lack of the related rules, regulations, standards and experimental In China, the first common utility tunnel was 1076 m long and built data from construction and operation. under Tiananmen Square in 1959 which transported , Two figures can illustrate the current situation and future trend of electric power, water and other utilities for Beijing citizens. A later utility tunnel construction in different Chinese cities in 2017 (see Fig. 5) milestone is that, in 1994, Zhang Yang Road tunnel in Shanghai was and 2020 (see Fig. 6). In Figs. 5 and 6, the main cities are shown on a built as the largest common utility tunnel in China to that date. It graph of GDP vs population while the size of the bubble stands for the showed a great service and anti-disaster ability which made the ex- total length of the utility tunnels built/expected in the city. ample significant for the developing of Chinese utility tunnels (Wang Cities that are closer to the upper right corner of the figure have a and Chen, 2006). In 2005, a three-floor utility tunnel was built in the higher permanent resident population and Gross Domestic Product, Zhongguancun west district, Beijing with the underground space de- with the opposite true for the cities in the left bottom corner. About 28 velopment. In order to support the 2010 World Expo with a higher main cities, including municipalities directly under the central gov- quality service, the government decided to build the first precast pre- ernment (near the upper right corner), provincial capitals and major stressed utility tunnel in China for the Shanghai World Expo. This pilot cities (most of them near the left bottom) are shown in the figures. provided key experience for later utility tunnel construction and man- Fig. 5 shows that big bubbles are concentrated in the left bottom and agement in China (Yang and Peng, 2016). Since then, other cities also small bubbles are scattered in the middle and the upper right part of the have built their own utility tunnels in important districts to raise the

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Fig. 5. Relationship among GDP, population and existing length of utility tunnels in Chinese cities in 2017.

figure. This is because long-length utility tunnels have been built in sewer and storm drains, gas pipelines and garbage collecting and pilot cities (e.g. Zhuhai) at the same time with the urban renewal transporting vacuum systems. In China, both gas pipelines and heating through overall plans. And more developed cities have preferred to pipelines should be separated from the other pipelines with an in- build short-length utility tunnels (e.g. Chongqing) because of the ex- dividual space and effective security measures (Huang, 2016; Zhang, cavation difficulties. Beijing, Guangzhou and Shanghai are the earliest 2016a; Mi and Luo, 2016). cities to build utility tunnels in China due to the growing demand and Some other countries have built utility tunnels since the 19th cen- their bubbles consist of many short-length utility tunnels that have been tury and they have developed proven techniques to allow a variety of built in different years from 1959 to 2017. It can be seen from Fig. 5 pipelines to work together in the same utility tunnels. Usually, the that the utility tunnel construction in these cities is still at the ex- utilities incorporated are decided based on the need of circumjacent ploratory stage up to 2017. Most of the cities have built less than 25 km consumers. In China, the type of utilities incorporated is limited be- length of utility tunnels to gather experience and meet the need of cause of the lack of experience and technique. So far, there are water special areas. supply pipes, communication cables, heating pipes, gas pipelines, Fig. 6 shows the utility tunnels that will be built by the government electric cables and garbage collecting systems in Chinese utility tunnels. up to 2020. The bubbles grow bigger and more homogeneous than in Electric cable ducts are very common in most Chinese utility tunnels Fig. 5 which means that the utility tunnels in China will undergo an which are installed with fiberglass supports. And there are no technical intensive construction period. Most cities shown in Fig. 6 will build barriers to have normal electric cables or high voltage power cables in more than 100-km of utility tunnels up to 2020 and the main emphasis the utility tunnels. The ventilation system, cooling system, fire pre- of construction will be transferred from the pilot cities to the bigger vention system and disaster prevention must be settled before their cities that have great needs. The average length of utility tunnels to be incorporation (Huang, 2016; Zhang, 2016a; Mi and Luo, 2016). constructed will be more than 120 km per city till 2020. But some pilot Water supply and recycled water pipelines are the oldest pipelines cities such as Zhuhai and Shiyan only need short-length utility tunnels in the utility tunnels in China. The pipe materials include ductile iron, to connect different districts which results in a small planning length of PE, steel and concrete. It is more safe, clean and easy to maintain such about 50 km. pipes in the utility tunnel when compared to the traditional direct burial. There are two kinds of discharge pipelines - drainage pipelines and sewage pipelines. A drainwater pipeline needs to be connected to 2.2. Type of utilities incorporated the numerous rainwater collectors above the ground which makes it difficult to incorporate a drainage pipeline in the tunnel. A sewage Most utility tunnels contain high voltage power cables, water pipeline typically depends on pipe gradient for its flow and may be supply, and communication cables; some of them even contain re- incorporated only when the utility tunnel can accommodate this gra- claimed water, cooling water, hot water or steam for district heating, dient or a pressure-driven flow is used (Huang, 2016; Zhang, 2016a; Mi traffic control signal cables and television cables; a few of them contain

Fig. 6. Relationship among GDP, population and expected length of utility tunnels in Chinese cities in 2020.

95 T. Wang et al. Tunnelling and Underground Space Technology 76 (2018) 92–106 and Luo, 2016). least space proportion and the reclaimed water pipeline has the least Compared to other pipelines, the communication cables/ducts (in- maintenance cost (39134 U. S. Dollars per year) with the least space cluding telecom and television cables, etc.) have more installation proportion (11%) at the same time. flexibility and are easier to move. So this kind of utility is readily in- The proportion of different pipelines incorporated is shown in corporated in the common utility tunnels to prevent the external nui- Fig. 10 on the basis of more than 100 typical cases of utility tunnels in sance and the repeated excavation that occurs with direct burial of such China. It can be seen that nearly all of the utility tunnels in China have utilities. On the other hand, attention needs to be paid on the optical water supply, power cables and telecom incorporated. Fewer utility fiber communication technology development, physical shielding tunnels would allow sewage and/or gas pipelines due to the design and technology and the electromagnetic interference among the pipelines safety issues. Some other utilities such as garbage collecting and themselves, especially in the information era (Huang, 2016; Zhang, transporting systems, television cables, heating/cooling pipelines, de- 2016a; Mi and Luo, 2016). salination pipelines, etc. would be selectively incorporated into the Gas pipelines and heating pipelines are allowed in Chinese utility utility tunnel because of the regional differences and special require- tunnels and there have been few accidents after years of operation. ments. Utility tunnels provide individual spaces, dry environment, better Some cases of existing utility tunnels show a great potential problem monitoring and maintenance for the gas and heating pipelines. Leaking for utility tunnels in China. The utility tunnels in Zhangyang Road of problems and construction disturbance can be prevented or controlled Shanghai have been used since 1996, but the utilities actually in- in a timely fashion in utility tunnels (Huang, 2016; Mi and Luo, 2016). corporated are less than the one tenth of the design capacity while no Garbage collecting and transporting vacuum systems have been water supply pipelines and gas pipelines are incorporated in the utility applied in some other countries since 600 years ago (Mi and Luo, 2016). tunnel. A similar situation happens in the utility tunnel of Anting New The system transfers the household garbage to a central collection point Town and Guangzhou Higher Education Mega Center. There are only using a vacuum which prevents secondary pollution and improves the 30% of the pipeline departments willing to be incorporated. Different efficiency of collection. The system has been used successfully in cities pipelines may have a potential impact on each other and they belong to like Beijing and Guangzhou (Zhang, 2016a; Ding et al., 2010). different departments which complicates the decision to have the pi- Other kinds of pipeline could be applied in common utility tunnels peline incorporated in the tunnel. Furthermore the pipeline/cable de- such as cooling pipes, control systems, detection systems, lighting partments are asked to pay the incorporation cost and the maintenance cables and fire suppression systems. In order to ensure safety of the cost for their incorporated utility while the incorporation cost is almost pipelines and meet the need of the customers, pipelines should be the same as the traditional laying cost and the maintenance cost is an considered for incorporation based on factors such as safety factors, extra expensive cost which most departments are unwilling to afford. space proportion and related cost. In general, gas pipelines and sewage For example, except the incorporation cost, the electric power company pipelines could be installed in a separated space to ensure the safety of of Guangzhou Higher Education Mega Center has to pay an extra cost of the utility tunnel (Hu et al., 2005). Utilities should be charged on the 131137.6$/year for the maintenance cost of their electricity cable. basis of space proportion and maintenance work. For example, 5 dif- These factors worsen the problem (Wang, 2015; Yu, 2013). ferent kinds of pipes are installed in one compartment of the utility tunnel in the Guangzhou Higher Education Mega Center, the space 2.3. Typical layout and route design proportion of per pipeline (see Fig. 7), maintenance cost (see Fig. 8) and incorporated cost (see Fig. 9) shows the space proportion, incorporated The utility tunnel has different types because of the various kinds of and maintenance cost of each pipeline. utilities pipelines incorporated (Canto-Perello et al. 2013). Each type From the figures shown above, it can be deduced that there are no stands for a special type of layout and design. obvious relationships between the space proportion and the in- The trunk utility tunnel is generally built more than 3 m deep below corporated cost. The heating pipe has the most expensive incorporated main and is used to transmit water, electric power, etc. from the cost while it only takes 16% of the space. The telecom and power cables original stations (e.g. water works) to branch tunnels and this kind of occupy 60% of the space while their incorporated cost is less than 20 U. tunnel would not serve the areas along its route directly (see Fig. 11). S. Dollars/meter. The maintenance cost seems to have more to do with A branch of the tunnel serves the users by distributing and trans- the space proportion. The power cable has the most expensive main- porting various supplies from a trunk line through the branch line tenance cost (more than 13 thousand U. S. Dollars per year) with the which usually contains water, telecom and other pipelines (see Fig. 12).

Fig. 7. Space proportion of each pipe in one compartment, in case of Guangzhou Higher Education.

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Fig. 8. Utility’s incorporated cost.

Sometimes similar pipelines within the tunnel may have different landscape that are undergoing massive development or re-develop- owners. For example, China Unicom, China Mobile and China Telecom ment. Some typical cases are explained below. can lay their telecomm lines in the same tunnel. The cable utility tunnels that carry electric, communication and 2.3.1. Constructed with underground space telecom cables would typically be built about 1.5 m below the sidewalk Beijing Zhongguancun Science Park (Z-Park) is a densely populated and incorporate different companies’ cables (see Fig. 13). high-tech industrial park which brings together a great number of Some utility tunnels are circular, elliptical (see Fig. 14) or multi-face companies and motor vehicles. Companies have different demands for tunnels (see Fig. 15). These configurations result from using special utilities which results in repeated excavation, traffic disturbance and construction methods (shield tunneling or pipe jacking) (Koyama, wasting of resources. Therefore, a triple-decker utility tunnel (see 2003), meeting the demands of the consumers or reducing the dis- Fig. 17) was designed to solve the potential problems that may happen turbance during construction (see Fig. 16). The rectangular and multi- in the future (Yang, 2005; Guan, 2009). cabin layout design is common in China and there are some circular and The designed route of the utility tunnel connects the 27 center elliptical utility tunnels in China while few multi-face utility tunnels parcels of the park (see Fig. 18). The utility tunnels serve the neigh- can be found in China. boring consumers, the incorporated traffic lane shares the traffic pres- The design routes of utility tunnels mostly depend on the status of sure and the underground commercial street enhances the utilization of the demand and the decision of local governments. The influence fac- underground space. Beijing Zhongguancun Science Park utility tunnel tors include existing pipelines, city metro system and any underground provides a successful example of constructing utility tunnels combined space development reserved space plan, geology. According to their with underground space creation which supplies a huge environmental, experience, the Japanese government prefers to build utility tunnels in economic and social benefit. In a similar fashion, the concept of a utility developing cities with a high population density because of the in- tunnel built with a subway line (see Fig. 19) has been accepted and creasing demands for public facilities and the impact of excavation. applied in some cases. European governments have built long and systematic utility tunnels to meet the growing needs of utilidors (Qian and Chen, 2007). In Taiwan, China, the utility tunnel law states that utility tunnels are 2.3.2. Constructed with major traffic artery built to improve the quality of life between urban and rural areas, in- The utility tunnel in Shanghai Zhangyang Road is a typical case of corporate pipelines and make a better and safer city. Local governments utility tunnel constructed in conjunction with a major road. Zhangyang in Taiwan have built utility tunnels in the center part of the city, Road is located in the Lujiazui Financial Centre, which is the business business districts, redevelopment areas new development districts, and office center of Shanghai. As an important road, tra ffic congestion, especially the new development districts (Peng, 2002). In most cities of blowing dust, annoying noise and repeated excavation are not allowed China, utility tunnel construction is just about to start. Also, most of the along the street. The government decided in 1994 to build a utility utility tunnels are passing through areas with a high demand for tunnel along Zhangyang Road to incorporate different pipelines/cables, serve the neighboring consumers and create a harmonious environment

Fig. 9. Maintenance cost of each pipeline.

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Fig. 10. Condition of pipelines incorporated.

(Wei and Meng, 1997). The 11.25-km utility tunnel is buried about 1.5 m deep beneath the sidewalk along Zhangyang Road which starts from Pudong South Road to Gold Bridge Road (see Fig. 20). As shown in the layout design of Zhangyang Road (Fig. 21), utility tunnels constructed in conjunction with a major artery must in- corporate neighboring pipelines as completely as possible to prevent future excavation and provide better service (Wei and Meng, 1997). Zhangyang Road utility tunnel contains several kinds of electric power cables, water supply, communication cables, television cables, gas pi- pelines and others (Cheng, 1995).

2.3.3. Directly serving a community Many cites in China develop in a radial way which makes it ne- cessary for the route designer to design a utility tunnel that can serve ff di erent districts at the same time. This common phenomenon makes a Fig. 12. Typical layout of a branch utility tunnel. ring-type route design of utility tunnels popular in many Chinese cities. The Zhuhai government decided to build a 33.4-km ring utility and the layout are shown in Figs. 24 and 25. The designed route of the tunnel to connect pipelines of different districts and serve the Hengqin utility tunnel will pass through 7 main roads and 5 districts of the city. Island in 2013. The 33.4-km utility tunnel connects 10 districts of the After completion, the service area will be about 40 km2 and the project island with power cable, telecom, water supply, recycled water, con- will benefitting about 0.35 million people. densate water, etc. incorporated in the tunnel (see Figs. 22 and 23). This was the longest and most expensive utility tunnel serving the largest area with the most types of pipelines incorporated till 2013 (He, 2.3.4. Directly serving a campus 2015; Zhang, 2016b; Li et al., 2011). The plan for building the Guangzhou Higher Education Mega Center The Baiyin government also decided to build a 61.1-km ring utility utility tunnel on Xiaoguwei Isle was settled in 2002 at the same time as tunnel to connect pipelines of different districts and serve as large a the construction of the Guangzhou Higher Education Mega Center. The proportion of the city area as possible (Cao, 2016). The route design 10-km utility tunnel was built 1.5–2.0 m deep under the intermediate

Fig. 11. Typical layout of a trunk utility tunnel.

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Fig. 13. Typical layout of a cable utility tunnel. ring road in a circular-distribution to serve the neighboring consumers VCjj× R = (see Fig. 26). The utility tunnel was finished in 2004 with power cables, j n ∑ ()VCjj× water supply, telecom, heating pipes and cooling pipes incorporated j=1 (1) which cost 98.5 million U. S. dollars in total (see Fig. 27)(Li, 2004; Wang et al., 2004; Ding et al., 2010). where Rj = the chargeable expense ratio of the pipeline department of j 3 kind; Vj = the space ratio of the pipeline of j kind (m ); Cj = the tra- ditional cost of the j-kind pipeline laying per cubic meter (New Taiwan 3 3. Governance issues Currency/m ); Vj × Cj = the traditional cost of the j-kind pipeline in the project; n = number of types of pipelines incorporated. 3.1. Financing criteria First-tier cities such as Shanghai which have a large population and construction density need to build utility tunnels in the key sections of The financing criteria are often the key issues when building a the cities. However, the governments of the first-tier cities can afford utility tunnel. In the USA, Canada and some European countries, di- one or more utility tunnels while some second-tier cities could have versified investment and financing modes have been used to solve the financial problems to build their own utility tunnels. To address this financing problems. And Japan has started to regularly build utility issue, the central government provides preferential policies to help tunnels since 1963 when the utility tunnel law has been settled. The law second-tier cities to build utility tunnels. In some pilot cities in China, says that governments at all levels should be jointly responsible for the such as Baotou and Shiyan, the local governments can apply for a construction cost which provides new ways to finance utility tunnels special low interest loan from the China Development Bank which helps that are more reasonable for developing countries to follow (Hou et al., relieve financial pressure. Except for the government investment, many 2005a,b). cities in China finance using public private partnership (PPP) modes. The situations of different cities in China with respect to common PPP modes in China can be roughly divided into three kinds. First, utility tunnels differ. For example, a utility tunnel law was issued in the transfer-operate-transfer (TOT) mode needs governments to pay for Taiwan province, which solved the problem of cost-sharing for a project the construction cost of the project and transfer the management right (Peng, 2002). The law says that the competent authorities should pay to the bid-winning department. In a build-transfer (BT) mode, the for one third of the construction cost and that a pipeline department government provides authorization to a project investor to take re- would share the rest of the cost according to its pipeline classification. sponsibility for the construction of the utility tunnels. After completing of the project, the government takes back the right of management and

Fig. 14. Elliptical utility tunnel in Hongzhong Road, Xiamen.

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Fig. 15. Multi-compartment design of a utility tunnel below the sea.

Fig. 18. Designed route of the Z-park utility tunnel.

Fig. 16. Layout design of shield-tunnel-constructed utility tunnel in Aoyama.

Fig. 17. Layout of utility tunnel in Z-park.

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Fig. 19. Utility tunnel constructed with subway line (concept). buys the project back on installment over a certain period (5–8 years) according to the predetermined contract. The third mode is the build- operate-transfer (BOT) mode. It requires the project investor to take full responsibility for the investment, design and construction of the utility tunnel. The investor could also keep the right to manage and operate the project in a certain period which is usually more than 10 years and hand the right of the management back to the government after the end of the operation period (Yu, 2013). Choices can be made according to the local situation of each city. For example, the TOT mode is suitable for a rich government with priority projects but it may increase the risk for the local government; the BT mode can relieve the pressure of the short-term financing which can be considered by cities under urban construction; the BOT mode is Fig. 21. Layout of the Zhangyang Road branch utility tunnel. more flexible and it can also relieve the financial pressure for the most part which is suitable for governments with financial problems. On the Assessment should be made to make sure the project has great potential other hand, the government must pay more attention to the contract to let the investors make the cost back and make a profit during the and the regulation since the government has no stock and management management period. Then it is necessary to use reasonable formulas to right during the operation period. Practice proves that PPP modes have solve the complex problem of cost-sharing arrangement of the con- worked out fine in Chinese cities. For example, the BOT mode has struction and management. helped the Baiyin government solve the financing problem. Value for money (VFM) is an evaluation method that can give the The investment structure of the project is diverse in different cities. assessment of the utility tunnel operated in PPP mode during its design For example, we can identify 3 big parts of the project from Fig. 28. life. VFM was first put into use in the UK, the UK government

Fig. 20. Route design of the Zhangyang Road utility tunnel.

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Fig. 22. Route design for the Utility tunnel in Hengqin Island. promulgated a guide of the VFM criteria after a long period of practical Fig. 24. Route design of utility tunnel in Baiyin city. and theoretical exploration which helped the UK government establish a standard evaluation system of VFM. This evaluation method has been learned by many countries such as the Germany, Singapore and China, and it has been enriched and improved to meet the special needs of different places (Gao et al., 2011). The public sector comparator (PSC) provides a method to assess the project by evaluating the cost of same quality of the productions and services in China. The other important issue of PSC is life-cycle-cost (LCC) which stands for the whole cost of the utility tunnel in its design life. The VFM is more than zero when the PSC is greater than the LCC which means that the utility tunnel is cost-effective and worth the in- vestment.

PSC consists of the original public sector comparator (PSC0), taxes and the risk evaluation. PSC0 is the construction, management and the maintenance cost of the project.

PSC0 can be calculated by the following formula:

PSC012=+ C C (2)

(1+−r )t 1 CA22=× × L rr(1+ )t (3) where C1 = construction cost (¥, decided by the local price control administration); C2 = management and the maintenance cost in its design life (¥/km); A = management and the maintenance cost of one 2 Fig. 25. Layout of utility tunnel in Baiyin city. year (¥/km); L = the total length of the project (km); r = base earnings ratio; t = calculating interest times. Related taxes include stamp tax (0.05% of the the contract price), Construction of utility tunnels in China are lack of experience and land tax, business tax, value-added tax, urban maintenance, construc- data. With reference to the risk transfer (W1) and risk retention ratio tion tax, etc. In the formula, B stands for the taxes. (W2) used internationally, W2 can be ignored because the government

Fig. 23. Layout of utility tunnel in Hengqin Island.

102 T. Wang et al. Tunnelling and Underground Space Technology 76 (2018) 92–106

Fig. 28. Investment structure of the project in Baiyin.

Fig. 26. Route design of the utility tunnel in Guangzhou Higher Education Mega Center. Table 1 Data of the Beijing Zhongguancun Science Park utility tunnel. ff ff would bear the risk retention and W1 is usually di erent in di erent Items Cost ($) situation. For example, W1 is about 12% in the UK PPP mode while the ratio is down to 8% in Australia. With these elements PSC can be cal- Utility tunnel’s structure 6.14 million culated by the following formula. Auxiliary equipment 1.47 million Pipeline laying 1.76 million PSC=+++ PSC012 B W W (4) Maintenance 0.232 million per year Stamp tax 0.05% of the the contract price The LCC can be evaluated by collecting and analyzing the data of Land tax 0.0044 per square meter the investment indexes of the utility tunnels which has been built. And LCC is related to the PSC and LCC. the formula is based on assumptions and international conventions. But 4 the parameter estimations are conservative which could make the LCC=××∑ () Liii M K practical VFM even greater than the computation (Liu et al., 2016). i=1 (5) where Li = the length of different projects (km); Mi = the investment indexes of different projects while constructing utility tunnels (US 3.2. Management

$/km); Ki = correction factors in different areas while constructing utility tunnels (Ki = 1 in general geological conditions, Ki = 1.05 in It becomes more complex when the tunnel contains both public and areas full of water, Ki = 1.04 in sandy soil). private facilities. In the beginning, utility tunnels have been communal facilities which are completely funded by the government in some VFM=− PSC LCC (6) foreign countries. The government owns the utility tunnels and rents For example, the Beijing Zhongguancun Science Park utility tunnel the tunnels to companies or departments to get money to run the utility can be valued using VFM. The construction area is about 25,253 m2, the tunnels. But usually there are no clear standards for the charge, so users construction length is about 1.9 km. The VFM can be calculated by the in different places would pay different rent to use the tunnel. This kind formulas above according to the data in Table1.(Liu et al., 2016). of management requires a perfect legal protection system and a rich government. VFM=−= PSC LCC PSC012 +++− B W W LCC Related policy and laws are needed to make the management of =++++−(9.37 2.60) (0.47 1.11) 1.05 12.44 utility tunnels become more and more reasonable. For example, the =>2.16million $ 0 (7) Japanese government announced utility laws to encourage the con- The result shows that the project is economically feasible although struction of utility tunnels, make clear the responsibility of the pipeline

Fig. 27. Layout of the Guangzhou Higher Education Mega Center utility tunnel.

103 T. Wang et al. Tunnelling and Underground Space Technology 76 (2018) 92–106

Fig. 29. Management modes for utility tunnels in China. departments and forbid open-cut excavation (Vitruvius, 1960). The law Table 2 said that the government needs to be responsible for the management of Charging standard for the management work in the Guangzhou Higher Education Mega the main part of the utility tunnel and the owner of the pipeline needs Center utility tunnel. to take care of their own pipeline after the construction. Sometimes the Incorporation cost Maintenance cost Space used for right for the management work of the utility tunnel could be empow- the pipeline ered or handed over to a special subordinate department. Sound policy and laws helped Japan became one of the most advanced countries in Drinking water pipe 82.7$/m 46978.6$/year 12.7% (DN/600 mm) terms of utility tunnels (Green, 2009). No-drinking water 61.6$/m 39134.2$/year 10.58% In China, the development of utility tunnels in Taiwan province is pipe (DN/ similar to that in Japan. Sound laws and policy helped Taiwan become 400 mm) experienced and advanced in building and managing utility tunnels Heating water pipes 204.81$/m 58701.2$/year 15.87% (Peng, 2002). But in most Chinese cities, utility tunnel management (DN/600 mm) ff Electricity cable 15.1$/m 131137.6$/year 35.45% su ers from a lack of experience and appropriate institutions. The re- Telecom 8.7$/m 93957.2$/year 25.40% lated state-owned enterprise hold the liability of the management of the utility tunnels and it can also choose companies to do the management work of the utility tunnels through public tender (Shun, 2008). For 3.3. Standards and policies example, the management modes of utility tunnels in Shanghai Expo Site are shown in Fig. 29. Due to the long history of use, there are more specific standards The bid-winning companies need to have the appropriate qualifi- internationally than in China but in fact the general design standards cation for the management work. The owners of the utilities who use for common utility tunnels are not well developed. Different utilidor the tunnel would pay for the management fund. There are three dif- systems seem prefer to develop their own designs and specifications. ferent management cost apportionment approaches in China. Some of the internationals standards may not suitable for utility tunnel construction in China. For example, rainwater recycling is considered in – ⎛ Vi Si ⎞ 70 80% of the Chinese utility tunnels while few foreign utility tunnels Wi = 0.5⎜ + ⎟ ⎝∑ Vi ∑ Vi ⎠ (8) recycle rainwater. The special national conditions in China make the use of international standards for utility tunnels inappropriate for fi where Wi = sharing coefficient of i kind; Vi = the space ratio of the adoption in China. The rst local design and construction standard for 3 pipeline of i kind (m ); Si = earnings of the pipeline of i kind per year utility tunnels in China is the construction standard of the utility tunnel in (¥/year); Shanghai World Expo (DG/TJ, 2007), many cities such as Beijing and Wuhan have developed their own standards for guidance of local utility VViiii+−()/∑ VVV× ∑ tunnel construction. But most of the standards’ research concerns trunk Wi = V (9) utility tunnels, so other types of utility tunnels must be taken into consideration in the future. 3 where Vi = the space ratio of the pipeline of i kind (m ); V = the The Chinese government is strongly encouraging utility tunnel 3 ∑ whole space of the utility tunnel (m ); Ri = Ci/ iCi; Ci = direct burial construction. The State Council decided to start utility tunnel con- cost of the i kind pipeline (¥). struction projects in 36 cities according to the report of the opinions on strengthening the construction of urban infrastructure in 2013 (Li, 2015a). ⎛ Vi Si ⎞ In 2014, several encouragement policies were announced by the central Wi = 0.5⎜ + ⎟ ⎝∑ Vi ∑ Si ⎠ (10) government to push utility tunnel construction, such as the national guidelines for developing a new type of urbanization (the State Council, ffi where Wi = sharing coe cient of i kind; Vi = the space ratio of the 2014), the circular on central financial support for carrying out the pilot 3 pipeline of i kind (m ); Si = earnings of the pipeline of i kind per year project of utility tunnels (Li, 2015b). The government has documented a (¥/year) (Chui et al., 2016). series of guidelines including the guiding opinions on promoting the con- For example, in the Guangzhou Higher Education Mega Center, the struction of utility tunnels in urban areas to introduce more suitable fi- owners of the utilities pay for the cost of individual utilities according nancing, constructing and managing modes to pilot projects (the State to the actual length of each pipeline and maintenance cost is charged Council, 2015). The minister of the Ministry of Housing and Urban- once a year based also on the designed cross-sectional space of the pi- Rural Development, Chen, at a teleconference of utility tunnel con- peline. The charging standard can be seen in Table 2 (Yu, 2013; Meng struction in 2016, emphasized the importance of utility tunnels for and Wang, 2006).

104 T. Wang et al. Tunnelling and Underground Space Technology 76 (2018) 92–106 pipelines and set a goal of starting more than 2000-km of projects in the growing demand for utilidors. coming year. (2) More ring or loop layout designs will be used in the future and About 69 cities in China have started building utility tunnels with a utility tunnels are more likely to be constructed in conjunction with total investment of 12.9 billion U. S. dollars in 2015. The investment of underground communal facilities. the various governments will rise to about 146 billion U. S. dollars per (3) Chinese administrators need to use the experience and advanced year in the next decades which means there will be an explosive growth technologies developed in other countries to set up their own of the market of utility tunnels in the future spurred by the en- standards and systems to reduce the risk and divergence while using couragement policies of the government and the gradually maturing PPP modes and doing management works. standards. (4) The construction of utility tunnels in China is at a stage of explosive development and facing a tremendous market opportunity. The 4. Discussion and future directions various encouragement policies and existing experience shows the great attention that the local and national Chinese governments pay Research for this paper shows that more than 147 cities in China to utility tunnels which indicates that there is a bright future of the will build utility tunnels to meet the growing demand of urban devel- development of utility tunnels in China. opment in the coming decades. In the future utility tunnels will extend to rapidly developing cities and pilot cities quickly. The size of the Acknowledgment utility tunnel market will be expected to reach 146 billion U. S. dollars in the mass very soon. This research was supported by the National Key R&D Program of Local governments will build their own utility tunnels by learning China “Public security risk prevention and emergency response tech- from the existing experience and finding the right way that is suitable nology and equipment”: Research and demonstration of urban under- for them. For example, the guiding principles of construction, management ground utility tunnel safety prevention and control technology. and maintenance work of utility tunnels in Wuhan area will be created to The authors are also very grateful to Dr. Raymond Sterling for his solve the special problems for utility tunnel projects in Wuhan. invaluable advice and suggestions. Common utility tunnels will become widely used to solve the de- velopment problems in urban areas and the demand of the public to not References be influenced by the construction technologies and to have a safe in- frastructure. 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