On Mumbai-Pune e-way, artificial tunnels to protect vehicles from landslides
The spate of landslides on the Mumbai-Pune expressway since the start of the monsoon has got the Maharashtra State Road Development Corporation (MSRDC) planning artificial tunnels on the stretch.mumbai Updated: Aug 05, 2015 17:53 IST
The spate of landslides on the Mumbai-Pune expressway since the start of the monsoon has got the Maharashtra State Road Development Corporation (MSRDC) planning artificial tunnels on the stretch.
The tunnel-shaped steel frames at Adhoshi and Khandala will act as a shield, protecting vehicles from the rocks and soil that rain down during a landslide.
“These artificial tunnels at Adhoshi and Khandala will be 100m and 340m long respectively. The tunnels will be built of prefabricated steel frames that can withstand the impact of boulders as heavy as 100 tonnes,” said Anil Diggikar, MSRDC managing director.
MSRDC will spend around Rs20 crore for the project, which will take three months to finish.
Since June 22, three major landslides have taken place on the expressway, causing loss of life and major snarls on the busy highway. Three people were killed in the July 19 landslide near the Adhoshi tunnel.
MSRDC is also taking other measures to protect against the natural disaster. It plans to instal sensors that will send real-time alerts about any abnormal rock movement. “The alerts will indicate the possibility of a landslide in the 2.2km ghat section, so we can immediately take precautionary measures,” Diggikar said.
Rock-cutting, grating and bolting is also planned, for which one lane of the road leading to Mumbai will be shut for three months.
The process will start off with MSRDC cutting a portion of the hill near the Khandala tunnel this week, during which traffic will be diverted to the old highway between 12pm and 4pm. The hill-cutting is priority, as loose rocks near Khandala are a threat. Then, the artificial tunnels will be installed. To fill gaps between rocks – to hold them in place – concrete grating will be done. The last step is hill-bolting, in which bolts will be inserted into the hill through the rocks.
Sources said these measures were put in place after MSRDC officials surveyed the ghat section with officials from the Geological Survey of India (GSI). Two firms, one from Italy and the other from Switzerland have also been roped in.
MSRDC has formed a legal and a technical committee that will investigate the cause for frequent landslides and frame a plan of action. The committees will submit their reports to MSRDC by September 30
* Geologists say rocks on the ghats are becoming loose because of the percolation of accumulated rain water
* To stop this from happening, MSRDC plans to build a drainage system to disperse the rain water into the valley
* Sensors will be installed in the ghat section to send real-time alerts about abnormal rock movement
* MSRDC will also carry out rock cutting, grating and bolting as precautionary measures. For this, one lane of the Mumbai-bound side of the expressway will be kept closed for three months
* Rs 20 crore is the amount MMRDA will spend for the repair work