Shani Wallis, TunnelTalk

Amid storms of negative press ahead of the Commonwealth Games, the first winner of the fixture is India's Delhi Metro. Its too had promises to keep as part of India's moment in the international spotlight. But where the Games' organisers have fallen well short of expectations, deadlines for the metro, set back in 2003 when the venue for the 2010 Games was announced, were, for the most part, met. The final section was inaugurated with only hours to spare, but efficient metro services to 10 of the 11 Games venues as promised were delivered by the publicly owned Delhi Metro Rail Corporation - DMRC.

The Airport Express Rail Link didn't make it. Awarded as a private PPP concession and with the civil works managed by the DMRC, the 22.7km line, with about 15.7km underground in TBM bored running tunnels, NATM work and open cut stations, the civil works were complete but testing of the trains and operating systems missed the mark.

Otherwise, metro services to 130 stations on a total 153km system were in operation - the last 15km underground link opening at 8am to provide services to the Jawaharlal Nehru Stadium for the spectacular opening ceremony that evening.

The train comes in on time for the Commonwealth Games

Some 1.5 million passengers per day are riding the system during the Games and patronage will remain high once the international visitors leave. The metro is a prized social and environment service to the widely spread metropolis with its heavily congested traffic corridors.

Remarkably, the 124.63km system in Phase II of the system has been built and commissioned in little more than seven years, the same seven years that organisers had to prepare for the Games. This includes about 31 km built underground in TBM bored running tunnels, lengths of cut-and-cover alignment, and in NATM mined work. "The original deadline set by the government for the completion of the Phase 2 lines was March, 2011," explained Anuj Dayal, Chief Press Officer for DMRC. "When the Delhi Commonwealth Games were announced in 2003, the deadline was moved forward to September, 2010, a deadline that was for the largest part met. A total 14 TBMs were working on Phase 2 at the same time and undoubtedly, more than a hundred contracts on six separate metro corridors were progressing simultaneously."

Once the Airport Link is commissioned, the full system will comprise 189.9km with some 43km underground - 11km on Phase I and 32km on Phase II.

Where three TBMs were used on the Phase I underground section, a total 14 machines worked on the bored running tunnels for Phase II and the Airport Link during the peak of civil works in 2008 and 2009. Add to this, there are long lengths of cut-and-cover construction and sections of careful NATM excavation with the largest percentage of the network on elevated stations and trackway. Most of the underground stations are open cut excavations with a particularly tricky NATM mined station on the Phase I alignment beneath the crowded Chawri Bazaar district.

Geological conditions for the underground works were highly variable. Delhi is built on the banks of the Yamuna River where water-bearing silts overlay a highly variable top of rock with a weathered quartzite interface and random outcrops of 100-250PMa Mica Schist, all under a high water table. The mixed conditions favoured EPB excavation and pipe-umbrella pre-excavation supported NATM excavations.

TBMs used on the project included Herrenknecht EPBMs and EPB machines supplied by Robbins, built in cooperation with Mitsubishi Heavy Industries of Japan at the Robbins facilities in China.

Complex mixed face conditions

The highly variable conditions caused their first serious change of plan on the first bored tunnel section on Phase 1 Line 2. A section of alignment planned by the Dyckerhoff & Widmann/Shimizu Corporation/Larsen & Toubro/Samsung/IRCON International JV as an EPBM excavation had to be changed to NATM excavation to compensate for very slow TBM progress through mixed face conditions that included tough quartzite of up to 250MPa. , The alternative plan proved highly successful and clawed back months of delay to bring the contract back onto its programme for hole through on schedule.

The alternative plan proved highly successful and clawed back months of delay to bring the contract back onto its programme for hole through on schedule. The first TBM breakthrough for Phase II Metro extension occurred on 31^st May 2008. The Herrenknecht machine broke through at Hauz Khas after completing a 1,450m run Huda City Line. The TBM was used previously on the first section of bored tunnels on Phase I in the centre of the city and by the same JV, led by Dywidag International. The second reused Herrenknecht TBM completed the parallel running tunnel to Hauz Khas.

Rock trap
A second run in with hard rock stumped an EPB drive on Phase II for the JV of Continental Engineering Corporation (CEC) of Taiwan and Soma Enterprise of India. The JV worked with two Herrenknecht and two Robbins EPBMs on its 7.3km long Huda City Line contract from Central Secretariate to Haus Khaz. It was one of its Herrenknecht machines stopped in its tracks by a outcrop of rock covering just less than half of the face area on the left side.

Of all the options, a change of cutterhead was selected as the most time and cost effective. After sinking an emergency shaft in a limited patch of ground over the TBM and alongside a main road, the soft ground head was replaced with a rock head fitted with disc cutters. Sourcing the spare rock head in Hong Kong and sinking the shaft cost the contract several months and a significant cost claim, but the plan had the drive finished successfully and in time for hand over of to the M&E and track work contractors to meet a line opening in September 2010, well in time for the Commonwealth Games in October.

CEC has gone on to win the first underground line contract for the Bangalore Metro.

Another four Herrenknecht EPB machines were delivered from the company's new assembly center in Chennai, to the Ital Thai Developments/ITD CEM JV for its Phase II Delhi Metro contract.

Airport Link
Three tunnelling contracts built the civil works for the Airport Link. Two Herrenknecht TBM bored 3.7km of alignment for the Alpine Mayreder/HCC/Samsung JV and another two EPBMs were used by the Shanghai Urban Construction Corp/Laren & Toubro JV for the 1.7km of bored tunnels and 800m of cut-and-cover work into the airport.

In between, the Alpine Mayreder/HCC JV built a 2.6km section of 10m diameter single-tube, double-track NATM tunnel, buying a new Atlas Copco jumbo for drilling in pipe-umbrella pre-support and assembling a shotcrete mobile on a track flatbed.

Costs and procurement
The Delhi Metro Rail Corporation, a joint stock company of the National Government and the New Delhi State Government.

The 65km Phase I scheme with about 13km underground was completed between 1998 and 2006 for a close out estimate of Rs.10,571 crores or about US$2.35 billion. Construction of the 125km Phase II network with 31km underground is estimated at about Rs 20,000 Crore or US$4.25 billion.

A mobile shotcreting robot

About 50% of the capital investment is funded via loans from JBIC (the Japan Bank for International Cooperation) with the rest allocated from national and state government revenues. The fare box and advertising revenues cover operations and maintenance. Loan amounts and interest payments to the value of Rs 567.63 crore or some US$125.45 million have been paid to the Japanese funding agencies.

Through the construction Phases, DMRC has had general advisory services from a JV of Pacific Consultants International of Japan, Japan Railway Technical Services, Tonichi Engineering of Japan, India's RITES rail authority, and Parsons Brinckerhoff of the US. The Corporations' Managing Director Dr E. Sreedharan however maintained a direct hands-on management style. Sreedharan, who previously managed construction of the Konkan railway line between Mumbai and Mangalore along the west coast, credits this in large part with meeting the Commonwealth Games deadline.

When TunnelTalk met with Dr Sreedharan in late 2008, he expressed his preference for the design-bid-build method of procurement as used for Phase I construction except the two underground construction contract. Design-build was adopted for them and for most of the Phase II construction to compress the civil works into a seven year programme to meet the promised Commonwealth Games deadline in October 2010. He remained however closely involved with decision making and problem solving, including the solution for the EPBMs stalled by the rock conditions.

TunnelTalk meets Dr Sreedharan in November 2008

Association with the Airport Link was a different procurement method again. The estimated US$900 million project was awarded as a PPP concession to the Reliance Energy- CAF Consortium of Spain to build, own and operate the line for 30 years. DMRC was appointed to manage the civil works and hand them over to Hong Kong's MRT (Mass Rapid Transit) Corp, which was contracted in turn to procure, install, test and commission all the M&E systems and rolling stock.

Civil works were handed over in early 2010 and the systems are all in place, but the operating safety clearances could not be secured in time for the Games. It is hoped that the line will open at the end of this month (October 2010) but it is disappointing that it missed the deadline. It was a flagship project specifically for the Games but that baton passed instead to the Metro itself, with its lines in services in time.

Problems however were not confined to the underground works. A major accident occurred in June 2009 when a section of elevated line collapsed killing six and injuring many others. Sreedharan accepted responsibility for breakdown of quality and safety procedures as the root cause of this worst ever accident on the project, and tendered his resignation but this was rejected. Sreedharan remained in place to see the project through to the October deadline, but he has said that he will retire at the end of this year. He was persuaded out of retirement at the age of 72 to take on the Managing Director post of DMRC in 2002 and was convinced again to stay on at the end of Phase I to manage Phase II, but at 78 this year he announced his retirement once Phase II was completed and the Games are over.

In a recent interview, Sreedharan, who is known as 'Metro Man' throughout Delhi and wider a field, said that integrity is the principal requirement for successful management and realisation of mega projects. Firm but fair is how he described his interaction with the many hundreds of contractors and project suppliers he has worked with. His integrity and dedication to the job has been recognised several times with several awards of distinction. Most recently he accepted the 2010 Outstanding Civil Engineering Project Award from the Asian Civil Engineering Coordinating Council (ACECC).

Dr. E. Sreedharan (left) receives one of many awards

As well as managing implementation of the Delhi Metro, DMRC offers its expertise to manage or advise development of mass transit systems in other cities. These include consultancy services for systems in other Indian cities including Bangalore, Mumbai, Hyderabad, Chennai, Kochi, Ludhiana and Pune and for extensions to the system in Kolkata and a high speed rail link to the airport in Hyderabad. Overseas, DMRC is a consultant to plans for a mass transit system in Jakarta, Indonesia. There are plans also for Phases III (112km) and IV (108.5km) in Delhi to be completed by 2015 and 2020 respectively. The network will then span more than 413 route kilometres with more sections to be built underground.

At the end of the Phase II works there are a number of highly skilled and experienced TBM operators and tunnel workers who are now searching for new employment positions. Several of these have notices posted on the Job Seekers section of the TunnelTalk website. Perhaps these tunnellers will find future work on systems in India itself and perhaps Dr Sreedharan will be persuaded to stay in post once again to kick start the next phase of mass transit expansion in Delhi.

References

Delhi Metro emerging - TunnelTalk, March 2002
Triumph out of tough going on Delhi Metro - TunnelTalk, October 2004
Underground advance for Bangalore Metro - TunnelTalk, July 2010
Current and planned tunnelling activity in India - TunnelTalk, July 2008
Job Opportunities - TunnelTalk

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