Status of underground space utilisation and its potential in Delhi

URBAN PLANNING AND DEVELOPMENT

Status of Underground Space Utilisation and Its Potential in Delhi R. K. Goel and A. K. Dube Abstract--Urban living in metropolitan cities of India is getting difficult day by day. It is difficult because the growth of population in cities is at a faster pace than the development of the cities. To avoid this situation underground or subsurface facilities have been created in developed countries. Japan has used underground facilities to a great extent in view of less land space available. The paper discusses some aspects of developing underground facilities in Delhi, the capital city of India, and the possibility of a road traffic by-pass tunnel. It is necessary that a master plan is prepared for underground space development in Delhi for its sustainable growth. Creation of an underground space city shall be the dream of all rock engineers and scientists of lndia forgood of the mankind. © 1999 Published by Elsevier Science Ltd. All rights reserved.

Introduction he population of cities is growing at a faster pace than the developraent of the infrastructure for the cities. This results in an increase in surface congestion. In this situation the cost of whatever space is available on surface becomes quite high. By the early part of the twenty-first century, the world can expect to have 4.5 billion additional people living in urban areas (Sterling 1996). It is estimated that by 2010, 50 percent of India's population will live in cities. This large population will need huge infrastructure in the form of transport, storage, living and office space, shopping arcades and parking lots, etc. The problems of developing countries affect the entire globe, both as a humanitarian issue and in t e r m s of practical issues such as global environmental problems and political instability. In European and other countries, various facilities have been constructed underground. These facilitiesinclude • underground parking space; • underground trafficbypass through tunnel forfaster transportation; • sewage treatment plants; • garbage incineration plants; • underground oil storage and supply of oil to various depots through pipelines in tunnels; and • underground cold storage.

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Going Underground (Winqvist and Mellgren 1988), a publication of Royal Swedish Academy of Engineering Sciences, is a useful document describing various uses of underground space. One outstanding example ofthe use of

Present address: R. K. Goel and A. K. Dube, Central Mining Research Institute,RegionalCentre,CBRI Campus,Reorkee -247 667 (India).

underground space is an underground ice hockey stadium with a span of 61 m , in Gjovik, Norway, built for the 1994 winter Olympic games. "Out of sight, out of mind" summarises the problem of creating public awareness of underground space, a remarkable resource that is still largely underdeveloped but available worldwide. The time is ripe for exploring the possibilities of developing underground space for civic utilities in India's megacities. It is pertinent to give the example of the Palika Bazar, an underground market in New Delhi. As part of the Cannought Place shopping area of New Delhi, the Palika B a z a r was built as a cut-and-cover subsurface structure with a beautiful garden created above it. If the Palika B a z a r was on the surface, the garden space would be lost and the surface congestion increased immeasurably. A challenge for developing countries is to find solutions that are effective, affordable, and locally acceptable, and which can be implemented at a rate t h a t keeps pace with the growing problems.

What Shell Be Done7 It is suggested t h a t a separate body be formed in India to study the systematic development of the underground space. Such an Underground Space Development Authority of India (USDA) could be established by the Ministry of Urban Development to guide the nation on policies of underground space development in an organized and efficient way. The USDA should have a large representation of investor and construction companies in private sector for ensuring successful implementation. Institutions like Central Mining Research Institute (CMRI) at Dhanbad with Regional Centers at Roorkee and Nagpur and University ofRoorkee (UOR) have the required experience in planning and designing of underground openings. Therefore, to begin with, the responsibility of preparing a master plan for underground space development for New Delhi could be assigned to CMRI and UOR.

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Benefits of Underground Space Development Subsequent to the development of a Master Plan for underground space development of India's megacities, various projects of underground construction may be started on the basis of BOLT (Built, Operate, Lease and Transfer). The advantages of a Master Plan would be: 1. A rapid decrease in the cost of underground space as underground facilities become operational. 2. A tremendous increase in the rate of growth of business opportunities in the cities because of future underground facilities. 3. An increase in hygienic conditions on the surface due to transfer of polluting industries underground. 4. A significant decrease in congestion of population on surface, as a large number of workers will be in underground industries. 5. An increase in the efficiency of workers in underground industries, as they will be working in a thermally comfortable environment that would be free from noise and air pollution and free from all the natural disasters. 6. A drastic reduction in the loss of life and property due to the high intensity of earthquakes, floods, tornadoes, landslides and cloud bursts, etc., for those living in underground space colonies. 7. During war, a reduction in loss of life and property, as people will be able to move safely into the underground defense shelters. The precious lives of the leaders can easily be saved by constructing very deep underground defense shelters. 8. An increase in job opportunities as underground construction picks up. 9. An increase in government revenue due to increases in the cost of land on the surface and underground. All underground land below a certain level should be considered government property.

Underground Space Utilisation in India m Present Status The earliest examples of underground structures in India were in the form of dwelling pits cut into the compacted loess deposits in Kashmir around 3000 B.C. and 500 B.C. This was brought to light by the Archaeological Survey of India (ASI) during excavations in 1960. These pit houses were found to provide excellent protection against cold and severe winter as well as heat of summer. They also offered protection against external attack. Dwellings belonging to 1600 B.C. were also noted at Nagarjuna Konda in Andhra Pradesh state. The world's most beautiful and elaborate rock tunnels, the rock temples in M a h a r a s h t r a state, cut out of the hardest rock and having a length of some kilometers, indicate early experience in engineering by humans. The tunnels of Ellora alone add up to 10.8 k m in length. In medieval India, forts and palaces were provided with fountains, underground pathways, basement halls for storage, meeting halls, s u m m e r retreats and water tunnels. The underground constructions in Daulatabad fort, M a n Mandir in the palace of King Man Singh, and the 17 basement chambers below the famous Tajmahal, are outstanding constructionsofmedieval kings ofIndia (Sharma and Selby 1989). The storyofRamayana mentions the town ofKishkindha, which was built completely underground and enabled its King Bali to win all battles. In the modern era, 11 underground powerhouse complexes have been built, 9 underground powerhouses are under construction,and 12 underground powerhouses are under planning for hydroelectricprojectsto generate 3000

350 TUNNELLINGANDUNDERGROUNDSPACETECHNOLOGY

MW, 7000 MW and 6000 MW, respectively (Rajvanshi 1997). The first metro railway project of India was taken up in early 1980s in Calcutta. The 16.45-km-long railway joins Dum Dum in the north to Tolly gunj in the south. The estimated cost of the project was Rs. 8.63 billion (approx. $US20 million). Construction of Delhi Metro will begin soon. Planning and investigations have been completed and global tenders might have been floated. Geotechnical information is given in IGS Symposium on Geotechnical Aspects of Metro railway, New Delhi, 1995. Nonetheless, in comparison to the utilization of underground space in developed and developing countries, India's modern uses of underground space have a long way to go.

Future of Underground Space Utilisation in India The future use of underground space utilization in India lies in the following areas: • Construction of J a m m u - S r i n a g a r Rail Line (project has begun). • Planning of Rishikesh - Karna Prayag Rail lines (project is in progress). • Construction of Delhi mass rapid transit system and vehicular traffic tunnels. • Many hydroelectric project with major underground tunnels and cavity complexes are planned in H.P. and Jammu, etc., in India, Bhutan, Nepal and Burma, with the help of Indian engineers, contractors and consultants. • Underground storage of petroleum products is under active consideration by IOC and other agencies. • Road tunnels such as the Rohtang tunnel, to serve poor people in hills and cities, are in the planning stage. • Globally organised corporations might build at least one large underground m a r k e t for selling their products in the hearts of metropolitan cities. The airconditioned underground markets will be highly pleasing and highly attractive to the consumers, in addition to providing safety from earthquakes, tornadoes, noise and pollution. In the long run, underground commercial complexes with underground parking lots and underground storage and underground link roads will be much more profitable than the distant surface markets. A global trend today is to use the underground space available below the existing railway stations in the megacities for commercial shops and markets. • A group of Indian companies is expected to team up with global companies to jointly bid on global tenders for tunnelling, hydro projects and other underground space technology. I n d i a ' s i n p u t i n these ventures can reduce the cost of construction significantly even in the most challenging geological and inhospitable conditions.

Requirements for Developing Underground Space In good quality rock (Q >10, where Q is Barton's Rock Mass Quality), caverns or underground cavities have been excavated to widths of 30 to 35 m with minimum reinforcement as support; but in fair to poor rocks like limestone, spans are often restricted to 10 to 20 m. The basic requirement for developing underground space is the presence of a good quality of rock mass. It is not that the caverns cannot be excavated in poor rocks, but rather that in poor rocks the construction of caverns is usually more expensive and therefore requires overriding technical and economic reasons.

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Expertise for const]mcting such cavities is available within the country. Underground construction is not new to Indian planners, designers and engineers. Since megacities of India are facing acute problems of surface congestion, it is pertinent to use the underground space wherever feasible. To s t a r t with, it m a y be adopted in Delhi. The megacity of Delhi needs to be developed in a planned and systematic manner, and utilisation of underground space would have significant benefits in this endeavour. To date there are few underground facilities in India except for a metro line in Calcutta and the projects mentioned above. The need for a metro and other subsurface facilities in Delhi iis obvious, and more concentrated efforts are required to achieve the goal. A scheme for an underground road traffic bypass is presented below. G r o u n d C o n d i t i o n s in a n d a r o u n d D e l h i

The terrain in Delhi is generally fiat except for a low ridge in the central portion of the region. Geomorphologically, Delhi is dominated by alluvial plains. The alluvial

plains are mostly fiat, interrupted by clusters of sand dunes and quartzites outcrops. The rock formations exposed in the Delhi area are mainly quartzites having thin interbeds of micaceous schist or argillaceous bands. The weathering is generally pronounced along the joint planes and gives rise to sub-rounded blocks of quartzites on the surface. The ground water under unconfined conditions (depths above 150 m) occurs in the silty to sandy layers of the alluvial sediments and also in the jointed quartzite having secondary permeability. Most of the rocky areas of Delhi are devoid of water because there are no or few aquifers. Therefore, loss of ground water because of underground construction should not be a major problem. If ground water exists in some pockets, it can be protected well by providing appropriate protection measures with the tunnel system. The depth of water table in alluvial plains is usually 2 m - 7 m below ground level. A geophysical refraction seismic survey conducted in Delhi area for the metro project reveals, in general, a threelayer subsurface with the longitudinal wave velocities as

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Table 1. Longitudinal seismic wave velocities of different layers in Delhi (Kadkade 1998).

Velocity (mlsec)

Layer

200-900

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2000-5000

Bedrock, quartzite (hard and compact)

The depth of quartzite exposures in Delhi is shown in Figure 1. The quartzite rocks are competent and hard and may be considered good tunnelling media in terms of stability and support. Generally, the rocks are good, but in places there are chalk bands. Such bands can be traced and these areas avoided in developing the underground space. Delhi is a historic city whose origin dates back 2500 years. There are indications of some underground tunnels, both natural and man-made, and it is necessary to conduct detailed surveys to trace them, as they may prove to be problematic for the development of underground space. A geophysical reconnaissance survey may be helpful in obtaining this information. The Problem

indicated in Table 1. Geotechnical investigations have been carried out along the proposed East-West and NorthSouth corridor (RITES 1990). The crushing strength of quartzites is of the order of abut 100MPa (Kadkade 1998).

With over 2.2 million motorised vehicles, in addition to a huge number of vehicles from the neighbouring states, Delhi is a nightmare for any traffic planner. Vehicles moving at a snail's pace in peak hours is a big problem for

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352 TUNNELLINGANDUNDERGROUNDSPACETECHNOLOGY

Volume 14, Number 3, 1999

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Figure 3. Tentative design of entry and exits. the travelling public and a great source of pollution. The Chief Minister of Delhi has proposed constructing an express highway costing Rs. 80 billion, connecting Karnal Road to J a i p u r Road in order to bypass traffic. The Minister also proposed development of warehouses and storage facilities in the vicinity of the express highway (Singh et al. 1998). In addition to road transport, there may be other needs, such as pedestrian crossings; underpasses below railway lines; metro lines; storage; storage for oil and gas; storage facilities for miscellaneous goods; and service tunnels for power and telecom cables. Underground water mains and sewage tunnels can be combined in highly congested localities. Proposed Scheme for an Underground Traffic Tunnel An underground bypass and storage facility m a y serve the purpose of super express highway very well and make it possible to build betl~er system within the budget allocated for the project, since the areas under reference have good rocks down below. The following paragraphs briefly describe such a scheme. The proposed traffic by pass twin-tunnel will start from Timarpur (North Delhi) and terminate near Sarita Vihar (South-East Delhi) to join Grand Trunk (GT) road. The total tunnel length is about 25km. At present the traffic

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runs using ring road and Mathura road (GT Road) for a total distance of about 21 kin. Though the surface route is shorter, the time required to traverse the distance is greater aboveground because of the heavy and mixed traffic. For through traffic, therefore, underground roads are very much essential and beneficial. The proposed twin tunnel alignment, shown in Figure 2, has been selected on the basis of the availability of quartzites (Fig. 1). The twin tunnels, each having a span of 10 m and parallel to one another, would be separated by a rock barrier of 20 m. The tunnels will be 25-30 m below the surface. This rock cover is sufficient for tunnel stability and there should not be any chance of subsidence of the surface land. These tunnels will be approached by inclined ramps with a gradient of 1:20 within the rock. The twin tunnel system will terminate near Sarita Vihar to join G.T. Road again. The tunnel system will have entries and exits ramps at m a n y points, including one in the vicinity of Jaipur road, to provide easy access to the roads on the surface as per the traffic needs. A general layout plan of twin tunnels on Delhi map is given in the Figure 2; Figure 3 shows the tentative design of entry and exit inclines/roads to the underground bypass tunnel. It is planned that one of the two tunnels in the twin tunnel system would be used for incoming traffic, and the other tunnel for outgoing traffic. This scheme separates the traffic moving in opposite directions and lessens the danger

TUNNELLINGANDUNDERGROUNDSPACE TECHNOLOGY353

of head-on collisions. Ten-m-wide t u n n e l s a r e sufficiently spacious to allow for t h r e e l a n e s of traffic as e n v i s a g e d for the proposed express highway. Close to t h e s e traffic t u n n e l s , u n d e r g r o u n d w a r e h o u s e s , go-downs a n d cold s t o r a g e s can also be e x c a v a t e d in t h e rocks. These a r e not shown in F i g u r e 2 b e c a u s e t h e y will be p l a n n e d as needs a r e identified.

Cost Analysis At the time of actually taking up the project the correct project costing would be worked out. However, the hypothetical exercise shows h o w m u c h the proposed bypass system would cost. As per the currently constructed tunnels in the Himalayan region, the cost of tunnelling for a hydroelectric projectroughly varies between Rs. 100 and 250 million per k m oftunnelling for a 10-m-diameter tunnel (approx.).The rocks ofthe Himalayan region are weak, and hence the cost of tunnelling will be higher in comparison to rocks of the Aravalli system. The cost of tunnelling in the case of Delhi quartzites m a y therefore vary between Rs. 80 and 100 million per kin. for a 10-m-diametor tunnel. As per the alignment given in Figure 2, the twin tunnels,exits,entries and other ramps would involve a total of about 50 k m of tunnelling. The cost of tunnelling m a y therefore will be around Rs. 5 billion. In addition, the ventilation and lighting m a y cost another Rs. 2 billion. Other similarly congested areas in India's megacities can be improved by going underground.

Conclusions •

The concept ofutilizationofunderground space isnot a new one for developed countries,whereas in India ithas yet to take on importance. The need at thistime is to generate awareness and confidence a m o n g the users to adopt underground space efficientlywherever it is available, in order to reduce the surface congestion and pollution for sustainable growth of megacities of India.

354 TUNNELLINGAND UNDERGROUNDSPACE TECHNOLOGY

* Because Delhi quartzites are good for underground construction, proposed schemes of road trafficbypass should be given due consideration. • Other underground facilities,such as defense and recreational centres, water collection,storage and treatment, sewage treatment plant, strategicoiland L P G storage, food storage, etc.,can also be planned. • A n Underground Space Development Authority (USDA) should be established for organised and efficientimplementation of underground space development projects in all megacities of India. Finally, the authors stress the following sentiment: Let us ensure that underground space is used for humanitarian missions only.

References Goel, R. K., Dube, A. K. and Singh, Bhawani. 1997. Concept of underground space for sustainable development of Delhi. Proc. Int. Conf. on Civil Engineering for Sustainable Development, 559-563. Kadkade, D. G. 1998. Construction methodology for underground structures at urban sites with special reference to Delhi Metro. Proc. National Workshopon Underground Space Utilization'98, New Delhi, 85-100. RITES. 1990. Report of Rites submitted to Delhi Metro Authorities. Also referenced in Kadkade (1998). Sharma, B. D. and Selby, A. R. 1989. Subterranean Ancient Structure of India. Tunnelling and Underground Space Technology 4(4), 475-479. Singh, Bhawani, Goel, R. K. and Samadhiya, N. K. 1998. Utilization of underground space in India - - present status and future potential. Proc. National Workshop on Underground Space Utilisation (UsU 98), September 1998, 1-30. Sterling, R. L. 1996. Going under to stay on top, revisited: results of a colloquium on underground space utilization, Tunnelling and Underground Space Technology U(3), 263-270. Rajvanshi, U. S. 1997. ISRMTTNews 6(1), January 1997. Winqvist, Torbjorn and Mellgren Karl-Erik. 1988. Going Underground, 170. Stockholm: Royal Swedish Academy of

Engineering Sciences.

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