The rock classification as per geological report submitted by the Detailed Project Report (DPR) consultant with respect to Silkyara-Barkot tunnel alignment ranges from poor to very good, Parliament was informed on Wednesday.
In a written reply to a question in the Rajya Sabha, Union Road Transport and Highways Minister Nitin Gadkari said the rock classification reported by the the EPC contractor during execution ranges from very poor to fair.
Gadkari further said to overcome the problem of weak rocks during tunnel construction, additional support such as shotcrete, fore poling, rock bolts, steel ribs, lattice girder, etc. have been provided.
Total 41 workers were trapped in the tunnel on November 12 and were rescued on November 28.
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The National Highways and Infrastructure Development Corporation Ltd (NHIDCL) is constructing the tunnel through Hyderabad-based Navayuga Engineering Company Ltd.
Silkyara tunnel is a single-tube tunnel divided into two inter-connected corridors by a partition wall. Each inter-connector corridor can work as an escape passage for the other.
The 4.5-kilometre Silkyara tunnel project in Uttarakhand, which is part of the Centre's 900-km 'Char Dham Yatra All Weather Road', aims to improve connectivity to the four pilgrimage sites.
Replying to a separate question, Gadkari said the road ministry is primarily responsible for development and maintenance of National Highways (NHs).
"Accordingly, average annual budgetary allocation of the ministry has increased by more than 940 per cent from about Rs 25,872 crore/year during 2009-14 to about Rs 2,70,435 crore during 2023-24," he said.
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According to him, length of 4-lane plus NH network including high speed corridors has increased by more than 250 per cent from about 18,371 km in March 2014 to about 46,179 km so far.
Also, length of less than 2 lane NHs has decreased from about 27,517 km in March 2014 to about 14,870 km, which is now only about 10 per cent network, he added.
