Bhoomipuja for Mumbai Metro’s Rs.23136 Cr Line-3 Colaba-Bandra-SEEPZ project held

The corridor is expected to be completed by FY20 and is estimated to carry 13.9 lakh commuters daily by 2021 and 17 lakh by 2031

Union minister Venkaiah Naidu is flanked by Dy CM Ajit Pawar (left) and CM Prithviraj Chavan during the bhoomipooja in Marol
Union minister Venkaiah Naidu is flanked by Dy CM Ajit Pawar (left) and CM Prithviraj Chavan during the bhoomipooja in Marol

मुंबई Mumbai: The Bhoomipuja (Foundation Stone) for the 32.5km-long Colaba-Bandra-SEEPZ underground metro rail project was held on Tuesday at Marol, paving the way for start of work on the Rs 23,136 crore project in a record time of 14 months since it was approved by the Centre. The project will connect Cuffe Parade, Nariman Point, Fort, Girgaum, Mahalaxmi, Worli, Bandra-Kurla Complex, Airport and SEEPZ. Construction work on the car depot planned at Aarey Colony will commence in September.

Union minister of urban development M Venkiah Naidu and chief minister Prithviraj Chavan were present for the function.

Last month, Mumbai Metro Rail Corporation (MMRC), which is developing the project on an engineering, procurement and construction (EPC) model, had invited tenders worth Rs 129.32 crore for the civil work at the metro car depot at Aarey Colony in Goregaon.

“We have already invited bids for the depot work and it is in the final stages. Later, in December, we will invite tenders for tunneling,” MMRDA additional metropolitan commissioner Sanjay Sethi told reporters on the sidelines of the ground-breaking ceremony.

The government has signed a loan agreement with Japanese funding agency JICA which will provide nearly 57 per cent of the total cost of the project or Rs 13,235 crore.

The Centre and the state will equally contribute for the remaining cost of the project, out of which Rs 777 crore will be borne by the Mumbai International Airport, since the metro will pass through the airport areas.

All barring one of the 27 stations of the metro will be underground. The one at the Aarey Colony, Goregaon on the northern fringe of the city will be at the ground level.

The corridor is expected to be completed by FY20 and is estimated to carry 13.9 lakh commuters daily by 2021 and 17 lakh by 2031.

The 27 stations on the corridor are Cuffe Parade, Vidhan Bhavan, Churchgate, Hutatma Chowk (Fountain), CST, Kalbadevi, Girgaon, Grant Road, Mumbai Central, Mahalaxmi, Science Museum, Acharya Atre Chowk, Worli, Siddhi Vinayak, Dadar, Shitaladevi Temple, Dharavi, BKC, Vidya Nagari, Santa Cruz,

Domestic Airport, Sahar Road, International Airport, Marol Naka, MIDC, Seepz and Goregaon. The MMRDA is also planning a 40-km metro line on the Dahisar-Bandra-Mankhurd sector with an estimated cost of Rs 30,000 crore

All stations to have platform screen doors:  The 27 stations of the underground metro rail will have platform screen doors. The platform screen doors act as barriers that don’t allow any commuters to fall on the tracks. These doors open only when doors of the metro rail and platform are parallel to each other. At least five construction methodology has been finalised for the project.

Cut and cover method for underground stations:  In this method of construction a trench is excavated and roofed over. There are two basic forms of this method. They are the Bottom-up and Top-down methods. In the first, a trench is excavated, with ground support as necessary, and the opening is constructed within. The trench is then backfilled with precautions regarding balancing compaction of the backfill material, and the surface is reinstated. The second method is the most suitable method for underground stations. But the road will be shut for a period of six months to a year.

New Austrian Tunnelling Method (NATM):  The plan is to construct 11 stations using NATM. In this method, the surrounding rock or soil formation of a tunnel are integrated into an overall ring-like support structure. The connection to the surface for entry and exit is generally provided by means of two shafts located at both ends of a station.

Temporary traffic decking arrangements:  This method will be effective to keep the city moving. In this, the king post will be useful. King post is a vertical structural support member to prevent the sagging of cross-beams. The prime objective is to support the traffic deck. In this temporary arrangement, construction of underground station will continue while the traffic is moving above.

Underground subways by Pipe Jacking Method:  Aimed at not infringing with building foundations, construction of subways will be challenging. Several longitudinal support members (pipes) are inserted side by side through the ground beneath the existing street. Number of longitudinal support members is also inserted along the height of the wall of the subway to be formed.

Underground tunnel between stations by Tunnel Boring Machine:  TBM, a highly-mechanised device, is an alternative to drilling and blasting. It’s advantage is to limit disturbance to the surrounding ground, and reduces construction cost in urban areas. TBM is much more efficient and it reduces total project time affected by tunnelling.