Control and prevention of gas explosion in soft ground tunneling using slurry shield TBM

For biogenic gas-rich ground tunneling, control and prevention of gas explosion is an arduous task. Until now, there is still a lack of reliable technologies to eliminate security emergencies such as explosion and combustion. In the present study, geotechnical investigations associated with the biogenic gas-rich ground at Sutong GIL Yangtze River Crossing Cable Tunnel have been summarized. The potential pathways for biogenetic gas to penetrate into the shield TBM and the excavated tunnel have been analyzed. Then, the adverse effects of biogenic gas on slurry shield TBM and tunnel construction progress have been evaluated. Finally, solution schemes including bentonite slurry penetration, clay shock method, gas detector system, explosion proof design, gas extraction system and wireless communication system have been proposed to mitigate the risk of biogenetic gas leakage and explosion. The application of these technologies has enabled the safety construction of long distance cross-river tunnel in organic-rich marine sedimentary ground.