Metro projects and hydropower schemes continue to drive India’s tunnelling market, and more opportunities are yet to come but challenges remain in the competitive market, Bernadette Ballantyne reports.Until the turn of the new millennium, India's tunnelling market was dominated by hydropower and irrigation tunnels, many of which meant drilling into the challenging geology of the Himalayas. "These are the toughest ground conditions in the world, closely followed by the Andes and then the Alps," says Manoj Verman, president of the Indian National Group of the International Society for Rock Mechanics (ISRM) and an independent consultant on tunnelling and rock mechanics. "The geology is very varied.It is not uncommon to encounter weak zones, shear zones, fault zones and water in the same path," he says noting that the high overburden stresses from the mountain can also cause problems. Combined with the inaccessible nature of some of the locations and the climatic extremes that include snow and flash flooding, working conditions are inhospitable at best and impossible at worst. It is clear to see why projects here are so challenging.Early TBM hurdlesDealing with the hard and changeable Himalayan rock has traditionally been a drill and blast affair, but the use of tunnel boring machine (TBM) appears to be gaining momentum despite an inauspicious start. "In mountainous regions TBMs have been used and the first three projects were a disaster," says Verman. "There is frequently changing geology and if a TBM goes fast it can get stuck and that is a nightmare. If the height of the mountain is very high it stresses too much and if the rock is soft then it squeezes, under the same height of overburden if the rock is strong then it will burst so these two are extreme cases and they both happen under high stress."An early example of a stranded TBM was on the Dul Hasti hydropower project in the Kishtwar district of Jammu and Kashmir, which began preliminary construction in 1985 and became operational in 2007. Shear zones regularly crossed the 9.64km head race tunnel alignment and water seepage was high leading to tunnel roof collapses that eventually buried the TBM, leaving it beyond salvation.Better progressHowever there have been some more positive breakthroughs. In June 2014 contractor and TBM manufacturer Seli announced that it had completed 14.7km of tunnelling on the Kishanganga hydropower project in Kashmir, mainly for construction of the 12km headrace tunnel. Revealing average rates of over 400m per month and a maximum of 816m in a single month, the scheme has been widely recognised as a huge breakthrough for mechanised tunnelling in the Himalayas. "This tunnel was a tremendous success," says Verman pointing to other forthcoming schemes that are planning to use TBMs. Client THDC India has appointed Hindustan Construction Company (HCC) to use a TBM for delivery of a 10m diameter, 12km long head race tunnel for the 444MW Vishnugad-Pilpakoti hydropower scheme in Chamoli in the state of Uttarakhand. The TBM is scheduled for delivery and assembly on site in February 2016.Long awaited success in the mountains combined with a huge demand for TBMs to build a growing number of city wide metro schemes, means that TBM manufacturers are upbeat about the prospects. TBM manufacturer Robbins established its Indian subsidiary in New Delhi in 2005."We started by supplying 10m double shield TBMs to contractors for an irrigation water supply tunnel which is 43km long. It would be the world's longest tunnel without intermediate access once completed," says Kapil Bhati, general manager for Robbins India, noting that the company's 10m-diameter machines are the largest in operation in India today. "The tunnel will take the water from a river and then over to a drought affected areas irrigating 500,000 hectares of land and further providing drinking water. We have completed around 25km as of now with two TBMs. We are still continuing and expected to complete 2.5 years from now," he says.Of course such a huge job has not been without its challenges and although boring of the outlet began in 2007 access to the inlet end was not available until 2011 due to land acquisition issues."After that advancements were pretty good even with geology being more difficult than anticipated. We are still doing around 300m/month average on each side of the tunnel so the production average is good in spite of the hard rock and tough geology," says Bhati.Another water tunnel transferring flows from the same river, is also underway using a third Robbins 10m-diameter machine. The tunnel is half way through with three years to go, says Bhati. A fourth 10m-diameter machine is also building a 12km water transfer tunnel.Metro growthAs these schemes roll on, Robbins has also been busy supplying and supporting machines for metros in India's bustling cities. "Soon after the irrigation tunnels the metro projects started," says Bhati and the company began by supplying machines to Delhi and then Chennai. "Delhi Metro was totally soft ground so we supplied a spoke type of earth pressure balance (EPB) machine. Those machines performed very well and had very good advance rates."The geology of Chennai is mainly soft but there are a couple of areas where there is rock or mixed ground and then we have supplied a mixed face EPB machine for that geology," he says."The result has been a more challenging bore in Chennai with rock at the bottom and soft ground at the top combined with ingress of water. Cutter changes and interventions were challenging but we have still been successful. There are around 200m left to bore."In Jaipur which is currently building the first phase of its metro starting with a 12km east-west connection, 2.8km of which are underground, the company met with soft ground. "The contractor had two old Robbins machines in stock so we refurbished those machines for the contractor and those are being used. The main challenge here is the heritage structures over the top. It is an old city," he says noting that in the areas where the metro transitions from elevated to underground there is just 5m of cover and yet the marginal tolerance is just 1mm.Tip of the icebergThese are just the tip of the metro iceberg. "Right now there are metros being built in New Delhi, Chennai, Calcutta and Bangalore. Elevated and underground both," says Sanjib Bhattacharya, chief of TBM tunnelling at ITD Cementation India, which is comprised of Italian Thai Development Public Company Limited with the Indian branch of the UK's Cementation. In his 22 years with the company Bhattacharya has delivered 50km of traditional tunnelling with NATM and 21km of TBM routes. "We just completed 7km of TBM tunnelling in Delhi. I was the project manager and out of 7km there were four EPB TBMs, two mixed shield and two soil all from Herrenknecht. In Delhi out of 36 machines, some 19 were Herrenknecht," he says. The Delhi metro is now undertaking its third phase of construction which will result in a further 160km of new lines 54km of which are underground. At its peak in mid-2014 there were 26 TBMs working simultaneously. The tunnelling is over 80% complete as Tunnels and Tunnelling goes to press and has not been without its challenges. Bhattacharya says that one particularly tough section was a 1.25km drive that ran beneath Delhi airport's runway for a distance of 400m meaning that the contractor was not able to carry out geotechnical investigations."This was very unpredictable because the geological data was not there. We designed our machine cutterheads and cutting tools on the basis of available geological parameters. It was around rock, we encountered quartzitic rock of around 200-210Mpa. Very, very hard. So in accordance with that we designed our machine to 250MPa. But unfortunately when we entered the airport area where the survey was not possible we encountered 350MPA," says Bhattacharya. As a result the construction costs ballooned from USD 14 to USD 15 per metre to around USD 35 as the hard rock quickly ate up the cutters. "It was a huge cost and meant that we were only getting four or five metres per day."As a result progress on this section was two to three months behind schedule, says Bhattacharya, however he points out that better progress on another drive where they avoided the rock and used the soil EPB machine made back the time.Despite having taken cores every 50m the nature of the airport site prevented investigation in this area and Bhattacharya says that the client accepted this when the contractor made a claim for the additional costs. "In India contracts are very rigid. 400m survey was not possible so we put a claim in and this was (logically) accepted by DMRC as the data couldn't be got in advance."Critical geological dataAs this experience shows, obtaining geological data is critical for any tunnelling project and is an area where Verman says that clients themselves need to put in more effort in the planning stages if they want to see their projects succeed. "The biggest lesson I would offer clients is 'please investigate more'. What is absolutely lacking in the country is proper site investigation or geotechnical investigation before the project," he says pointing to a World Bank study which he led five years ago which reached the same conclusion. "In state of the art projects 3–5% of cost is spent on investigations but in India it is not even 0.5%. People always say they have had geological surprises. They are surprises because they are not investigating. That is the biggest lesson that should be learned.""I fully agree," says Bhati. "There is hardly any sufficient data available before the tendering process commences. We understand regarding areas which have the limitations like Himalayas wherein the cover above the TBM is as high as 1 to 2km. On the other hand, water transfer tunnel projects or metro projects have the accessibility of lands which clients want to cut short by not providing the proper information or doing proper geographical mapping which results in the award of the tender to the contractor as it is," he says."The contractor in turn has to gather that information by himself which takes time therefore delaying the project and losing more time. Better and earlier information on geological details allows the manufacturers to design the machines and give them provisions to equip the machine to encounter all the problems in front."One of the side effects of this is that projects are less attractive to international contractors who are not prepared to take the risks pushed onto the contractors under the design and build arrangements. "For the time being, due to aggressive local competition and actual contract versions comprising unacceptable risks for the contractor, we refrain from tendering for tunnel projects in India," a spokesperson for contractor Strabag says.Yet ironically clients are demanding that international firms participate in main contracts. "Indian clients are putting a condition [in place] that the tunnelling manager must be an expert from outside of India," says Bhattacharya who says that the international financing provided to the metros also pushes for European consultants to be involved."It is true that they have more experience than us but the fact is that we are building experience. I have a team now running four TBMs simultaneously and now I am looking at Mumbai and Kolkata. We have the resources. Only problem is that the Indian companies don't have the technical credentials so they can't pass the technical bids so that is why we are making JVs."However he says that this is changing and that for smaller bores of 1-2km Indian contractors are wining projects without international partners. Another advantage that local firms have is their proximity to clients and their long term market positions which mean that local companies are more willing to accept delayed payments through claims. International firms however see this as too risky.One way of reducing risk, says Bhati is to have the TBM manufacturer support the project through its life, not just at the beginning. "Most of the time delays are because manufacturers are not supporting the project and the contractor is not capable of coping with the difficult geology. On most of the jobs what we are doing we are supporting them on execution on a per metre basis," he says.This strategy has been particularly important to the Bangalore metro for which delays have been widely reported in the local media. Mumbai Metro Line three"On Mumbai Metro there are seven packages and we got package four," says Bhattacharya whose firm ITD Cementation are in joint venture with Continental Engineering Corporation of Taiwan and Tata Projects. Financial bids were opened in October and Tunnels and Tunnelling International understands that the client Mumbai Metro Railway Corporation is currently scrutinising the project budget which is lower than the forecast costs. One of the major issues which will be faced in the execution of metro tunnels in Mumbai city will certainly be the rock strata which will push up the tunnelling costs. The entire 32.5km line is underground."Geological survey suggests 90% rock which will vary from 50 to 150MPa," says Bhati who has first-hand knowledge.Contracts for this line are yet to be signed . Other MetrosMumbai may be the next major project set for award but there are many more on the horizon. "Phase four of Delhi is coming with 90km of tunnelling. Bangalore phase one is about to complete and phase two is coming next year. Chennai phase three coming next year. Kolkata has another two underground packages coming," says Bhattacharya also pointing to forthcoming schemes in Lucknow in Uttar Pradesh, Hyderabad and Puna."The market is very promising perhaps one of the best in the world at this time, says Verman. "Now is the time that the country has to start moving into delivering infrastructure in difficult areas. Many projects are already sanctioned but procedures are such that they are not tumbling out in the way that we expected. However remain very optimistic. I am expecting 2016 to be a crowded year."Data from the Timetric Construction Intelligence Center places the value of work underway with a tunnelling element at USD 31bn however given the scale of projects planned — Verman says there are 3,000km of tunnels in the pipeline, the figure seems likely to rise substantially over the next five years."I was involved in planning a railway through the Himalayas from Rishikesh to Karnaprayag, 125km long alignment of which 105km is in tunnels so that is the kind of project you are looking at and for this kind of distance you have to use TBMs, especially for the longer tunnels," he says.Bhati of Robbins points to four main growth areas for the TBM tunnelling market. "We have hydropower projects in the pipeline which we see being awarded in 2016 and a couple of them will be using heavy provision of TBM. Then the metros like Mumbai which will be awarded in the next few months.Bangalore and Chennai are planning phase two. Seeing the success of Delhi, Bangalore and Chennai everyone sees that it is the best solution possible. For the next 10-15 years one city after the other will keep having metros come up," he says.Water transfer tunnels to divert much needed resources is also a priority, as are road tunnels. "These are the future. People have realised that there is limited space available above ground so we have to go under. There is a 22km underground tunnel in Mumbai which is going to come from the southernmost part of the city through the coast to the airport. It is entirely underground and will be about 12m diameter, and has now been approved.”Learning from the pastExpectations are therefore high for India's growing and maturing tunnelling industry, but challenges remain and Verman urges government to learn from the past in terms of better planning and reducing bureaucracy so that contractors are able to get on and deliver. "There are huge projects coming forward and government should support this industry and nurture it because it is in the government's interest that these projects are built.”
Hydro projects of all stages continue to make Asia a growth sector, says Patrick Reynolds. Among the many hydropower projects in development in Asia, expansions are underway at the Baglihar scheme in India, the Tarbela dam in Pakistan, and Lamtakong Jolabha Vadhana pumped storage plant in Thailand.Also in Pakistan milestone progress has been achieved recently at Neelum Jhelum, and studies are advancing plans for Thakot and other projects in the Indus basin.A range of further supporting studies for hydro projects are underway in Nepal and Bhutan, respectively, and also Vietnam — including Lai Chai where works are advanced. A refurbishment project is in preparation for a key hydro scheme in Tajikistan.Nepal also has a focus on irrigation needs, including a wider examination of flood hazard risk.Himalayas/Central AsiaIndia: Baglihar-II The 450MW Baglihar-II project in Jammu & Kashmir, India, was inaugurated recently by Prime Minister Narendra Modi. Developed on the Chenab River, the project is the second stage of the Baglihar scheme and doubles the installed capacity at the site to 900MW. The Stage I plant was built over 2000-2008. Their joint output is expected to be approximately 4180GWh of electricity annually.Project developer is the Jammu & Kashmir State Power Development Corporation. Lahmeyer International — part of Tractebel Engineering, a division of ENGIE previously GDF Suez — is the Engineer-in-Charge of the Baglihar site, and since 1999 has had engineering responsibilities on both stages of the development.Contractor on both stages is Jaiprakash Associates. E&M supplier on Stage II are Voith Hydro and Andritz Hydro, and for Stage I were Voith Siemens and VATECH, respectively.Both stages are served by a 144.5m-high concrete gravity dam with an integrated overflow spillway. Each stage also features significant underground infrastructure. The intakes to both are located in the bank, immediately upstream of the dam.The stages have parallel diversion tunnels at the dam. The headrace tunnels also run together for most of their distance, and each has a 77m high surge shaft.The underground powerhouses of the two stages, each with 3 x 150MW Francis units, are close together — Stage II complex is located immediately upstream of the Stage I caverns. The cavern complexes are approximately 180m apart.Each powerhouse cavern is 50m high x 24m wide x 121m long; and, the transformer caverns are 24m high x 15m wide x 112m long. The caverns were excavated over 2011-2013.Downstream of each powerhouse complex are further underground works, located before the tailrace tunnels: the underground structures are ‘Collection Galleries’. For Stage I, the collection gallery is a single cavern; for Stage II, the system includes a lower gallery 20.6m high x 14m wide x 95m long, three 14m-wide riser shafts and a gate operating top gallery 9m high x 16m wide x 57m long.The tailrace tunnels are different, too — Stage I is short (130m), high (29m) and flow is free-flowing; Stage II is a 350m-long, 10m-diameter pressurised tunnel.Other projects on the Chenab that Lahmeyer has worked on include Sawalkote, Ratle and Pakal Dul.Separately, in Himachal Pradesh, Lahmeyer recently provided consultancy services for the Thana Plaun project being developed on the Beas River by Himachal Pradesh Power Corporation. The 187MW scheme involves dam works and an underground powerhouse, and is expected to generate about 530GWh annually.Pakistan: Thakot Investigations are underway to prepare a feasibility study for the Thakot hydro scheme being developed on the Indus River by Pakistan's Water & Power Development Authority (WAPDA).Thakot is being developed as a project of at least 2GW, and is located immediately upstream of the existing Tarbela reservoir. It is part of a cascade of large hydro schemes planned to be built on the river, and upstream projects include 2.4GW Patan and 4.5GW Daimer-Basha.Lahmeyer is working with local partners on studies for the three WAPDA projects — Thakot, Patan and Daimer-Basha, respectively.The next project upstream from Thakot in the Indus cascade is Patan, and others being planned include Dasu and Daimler-Basha, which is 315km upstream of Tarbela dam.For the Thakot project, WAPDA is seeking to exploit a head of approximately 180m between Patan and Tarbela. Planning studies for Thakot are investigating options for either a single project or a few created as a small, intermediate cascade, says Lahmeyer. Thakot dam site is at a narrow section of the river, just downstream of Besham.At Tarbela itself, WAPDA is currently constructing the 4th Extension Project at the site to add 1410MW by June 2017 — an earlier deadline to an accelerated programme, announced in January. The extension will increase the installed capacity at Tarbela to 4888MW.Civils works on the 4th Extension Project are being executed by SinoHydro, and the E&M package is being supplied by Voith Hydro. Consultants working on the project are Mott MacDonald and Coyne et Bellier with subconsultants MM Pakistan and ACE Pakistan. The consulting team has also undertaken studies for the 5th Extension project.Tarbela was completed in the 1970s, and generating units have been added in phases up to the early 1990s.An earlier project for Lahmeyer was a feasibility study review for the high-head, 34MW Harpo scheme, on a tributary on the Indus. Separately from Indus developments, WAPDA noted the milestone progress achieved in underground works in February, with a key tunnel breakthrough on the 969MW Neelum Jhelum scheme. The project is to be commissioned over the second half of 2017. Contractor is Chinese consortium CGGC-CMEC. Consultants are Neelum Jhelum Consultants, which is a joint venture of MWH, Norplan, Nespak, ACE and NDC.Tajikistan: Qairokkum rehab ILF is providing consultancy services to national utility Barqi Tojik for the rehabilitation, uprating and safety improvements at Qairokkum hydro plant, in Tajikistan.The 66-year old plant on the Syr-Darya River is to have its capacity increased from 126MW to 174MW, and various E&M and civil engineering packages of works undertaken for the rehabilitation.The project is also to deliver dam safety improvements, the quality of electricity supply, and climate change resilience.ILF will provide services during procurement and construction phases, and commissioning.Funding support for the scheme has been given by the European Bank for Reconstruction and Development (EBRD).The bank also — along with the World Bank and European Investment Bank (EIB) — has given funding support to the related CASA-1000 transmission line project, which will help Tajikistan export hydropower to the Kyrgyz Republic, Pakistan and Afghanistan. Mott MacDonald has also carried out climate resilience studies on Tajikistan's water sector for the Asian Development Bank (ADB).Nepal Consultants Lahmeyer, Total Management Services (TMS), Entura and Manitoba Hydro International (MHI) are working across a number of water studies and projects in Nepal. The different contracts range from flood hazard studies and providing consultancy services to the Nagmati irrigation scheme and development of Tanahu hydro project, respectively.Lahmeyer is working with local partner TMS on flood hazard studies in 25 key river basins — including a focus of mitigation measures in six catchments — for the Ministry of Irrigation. The studies were due for completion in the first quarter of this year.The client division managing the task is the ministry's Water Resources Project Preparation Facility (WRPPF), which has ADB funding support to focus on urgent projects to mitigate both climate change impacts and ensure sustainability of food supply.Separately, the ministry and ADB have commissioned Entura as lead consultant for the initial services of investigations and updating the feasibility study of the Nagmati dam, near Kathmandu.Following consultancy services will include detailed design of the dam and reservoir operation regime, and assistance with procurement for the construction stage of the project to be built in the Bagmati river basin.In hydropower, development services for the 140MW Tanahu hydro project — the country's first large storage reservoir — are being provided by Lahmeyer with the support of MHI.The consultants were appointed to the project last year by the developer, Tanahu Power Ltd, a special project company established by the Nepal Electricity Authority (NEA) to build and operate the scheme.Tanahu is located on the Upper Seti River, and key infrastructure includes a 140m high gravity dam, chute spillway, underground powerhouse and associated tunnels. The reservoir will have a sediment flushing capability to help maintain the active storage volume.Bhutan The World Bank has appointed ÅF — a Swedish engineering and consulting company — to undertake an environmental and sustainability study of the 720MW Mangdechhu hydro project, currently under construction in Bhutan.ÅF is more than half way through the assignment on the Mangdechhu project being built in Trongsa Dzongkhag district in the centre of Bhutan.The run-of-river scheme is designed to operate under a minimum gross head of 344m, and includes significant dam and underground works: a 101.5m high concrete gravity dam, diversion tunnel, 13.5km long headrace, and powerhouse caverns.The consultant is due to report its findings to the bank and Bhutanese authorities before the middle of this year. The work is being conducted in accordance with the Hydropower Sustainability Assessment Protocol, which covers a wide range of areas, including climate change and human rights.The Mangdechhu scheme is being developed by Mangdechhu Hydroelectric Project Authority — a joint venture of the governments of Bhutan and India, the latter providing most of the finance. The project is due for completion in 2018, generating more than 2900GWh/year, and supplying power domestically and to India.In fiscal year 2006-7, India's NHPC entered into an agreement with the Government of Bhutan to prepare a detailed project report of the proposed scheme, then envisaged with a capacity of 672MW. Feasibilities studies for the scheme were supported by Japan and Norway.SE AsiaThailand: Lamtakong Jolabha Vadhana PS, Phase 2 ÅF is supporting the Electricity Generating Authority of Thailand (EGAT) on the extension project to double the capacity of the 500MW Lamtakong Jolabha Vadhana pumped storage plant.The underground plant has two pump-turbines in operation, and was initially commissioned in 2002. The 500MW expansion project at Lamtakong Jolabha Vadhana is due for completion in late 2018.Lamtakong Jolabha Vadhana is located in Nakhon Ratchasima province, was the first underground plant hydro facility in Thailand and remains the principal plant supplying power in the northeast provinces, says Electricity Generating Authority of Thailand (EGAT). Its upper reservoir is on Yai Tieng Mountain, and the powerhouse in 350m underground.Phase 2 of the project will add two further 250MW units, taking the total capacity of the PS plant to 1GW. Work at the plant is also to include installation of two circuits of 95km-long high-voltage transmission lines to connect with the Tha Lan 3 substation, in Saraburi province.ÅF signed a contract with EGAT to provide a range of services while the extension project is executed under by an engineering, procurement and construction (EPC) contractor.The consultant's services include design review, project management, engineering and field services through all stages of execution, including commissioning.Vietnam: Lai Chau HEP ÅF is also active in neighbouring Vietnam, where the consultant most recent began work on the supporting the implementation of the environmental and social action plan for the Lai Chau hydro project.The 1200MW Lai Chau project is under development on the Da River, in Lai Chau province, in the northwest of the country close to the border with China. Construction of the 131m high roller compacted concrete (RCC) dam at Lai Chau was completed in mid-2015.Lai Chau is being development by Electricity of Viet Nam (EVN). ÅF has already been working on the project as sub-consultant to Power Engineering Consulting JSC No1 (PECC1), a former subsidiary of EVN, and the assignment continues to 2017.ÅF was awarded the environmental and social action plan contract by Son La Hydropower Management Board (SLaMB). The board and ÅF worked together previously on the 2400MW Son La project, on the same river and also featuring a major, 138m high RCC dam. Son La was completed in early 2011.The environmental and social action plan contract for Lai Chau is funded by KfW, and ÅF is already working on another contract in Vietnam funded by the German development bank — gap analysis on environmental aspects of a smart grid transmission project. ÅF says the contract is similar to the objectives at Lai Chau by checking environmental and social due diligence, in this case for 6 x 220kV transmission lines.
As delays in projects go, being held up by almost 350 years is a big one. The idea of building a shipping canal across Thailand’s Kra Isthmus, reducing the usual trade route for ships between the Indian and Pacific oceans by more than 1,200km, was first mooted in 1677. However, despite the proposal resurfacing in the 20th century, fears over the environmental impact and the potential for it to divide the country have held it back. Now, the Korea Railroad Research Institute (KRRI) has put forward the idea of a ‘dry canal’ to carry ships across the south of Thailand, from Kra Buri to Chumpon Bay in the Gulf of Thailand, bypassing the Malacca Strait.
When workers broke through the Eurasia Tunnel in August 2015, it marked not only the first time Europe and Asia were connected by a road tunnel, but also represented the crowning achievement for one of the world’s most challenging tunnelling projects.