In the second half of 2016, the last earth pressure balance shield “Krishna” advanced 750m in complex stratum of Bangalore Metro and the tunnel was run through, which marked Phase 1 of Bangalore Metro finishing tunneling construction.
Phase 1 of Bangalore Metro is divided into east-west line and north-south line, overall length is 42.3km and 40 stations will be installed. It includes 4 elevated sections and 2 underground sections. Overall length of tunnel segment is about 5100m, inner diameter is 5.6m, which is divided into 4 sections of double-track tunnels: 970m, 750m, 432m and 400m. There are 7 5.6m-diameter earth pressure balance shield and 1 slurry balance shield tunneling.
During construction, poor, complex geology and hard rocks seriously reduce construction speed, even cause cutter head of shield tunneling machine break.
When encountering fracture surface soil, compound stratum and hard rock stratum, self drilling anchor bar can be operated with shield machine. It combines drilling, grouting and anchoring together, bonds surrounding rock and soil to self drilling anchor bar through slurry, which can then increase cohesiveness and enhance construction efficiency.
It’s reported that line will be operated in 2017.