Design Strategy of Tunnel-12 Passing Through a Regional Churachandpur-Mao-Fault in the Tupul Imphal B.G, Line Section in India

In this study, we have thoroughly investigated the design philosophy of the Tunnel No 12 which is of 11.55 Km length passing through the active Churachandpur-Mao-Fault across the Tunnel. There are also several faults namely Dalang fault, Langka Fault Kadi Fault and Kabaw Thrust etc. are located around the Tunnel No 12. The proposed Tunnel No 12 is located in seismic zone V which is marked as the highest seismic zone in India. Based on the past seismicity, there may be a possibility of occurring earthquake of magnitude Mw 8.5 in the seismic zone V. With this in back ground, earthquake response of the Tunnel No 12 has been investigated due to the active Churachandpur-Mao-Fault which has passed across it. The soil profile across the section is widely varying from hard to medium shale, soft sand stone, dense sand and a combination of sand silt and shale. As the geological setting across the tunnel is changing so stiffness of the tunnel also gets change. Elastic materials have been placed at the bottom of the Tunnel passing across the fault to reduce the vibration.