Civic body is shelling out Rs 1.12 lakh to understand the roughness of the rock and soil in the proposed tunnelling area
The coastal road will start from Princess Street Flyover at Marine Lines and will pass under Girgaum Chowpatty, Malabar Hill and emerge near Priyadarshini Park
In a bid to control the cost of the proposed tunnel for the ambitious coastal road, the civic body will be conducting a rock and soil test -- Cerchar Abrasivity Index Test (CAIT) -- between Girgaum Chowpatty and Priyadarshani Park.
The proposed coastal road alignment has two tunnels, Princess Street to Priyadarshani Park, and another one from Juhu beach.
According to civic officials, the test will help understand the roughness of the rock and soil in the proposed tunneling area. This will give the consultant designing the Tunnel Boring Machine (TBM) a rough idea of the estimated tunnel work. "Knowing the exact nature of rock and soil will also help curb the cost of tunnel work," said an official from the BMC.
The 29.2-km-coastal road will start from Princess Street Flyover at Marine Lines and will pass under Girgaum Chowpatty, Malabar Hill and emerge near Priyadarshini Park. The civic body has split the project into two phases -- Princess Street to Bandra-Worli Sealink and Bandra to Kandivli -- to speed up the work.
A senior civic official from the coastal road department said, "The rock and soil sample from the proposed tunnel area that was taken out during the geo-technical survey will be given to IIT-Bombay for CAIT. About 25 samples will be provided to IIT to analyse the abrasivity of the rock and soil. The test results will be out in a month."
The test will cost the civic body R1.12 lakh. The cost of the coastal road has already shot up from R11,000 crore to R15,000 crore.