Failure behavior investigation of loess metro tunnel under local-high-pressure water environment

With the acceleration of urban metro construction in the Midwest of China, the metro tunnel is inevitably crossing the collapsible loess site. For the metro tunnels in loess area, if the around potential water source is induced by external disturbance, the tunnel structure which is con-structed or being built will be influenced in the affected area of loess collapsibility. In view of this, model tests were designed according to the different water source positions and tunnel lining forms to study the collapsibility of loess and the failure behavior of metro tunnel under high-pressure water environment. And fluid-solid coupling calculation was conducted under different conditions of water source pressure, water source distance and water source location. Furthermore, the results were compared and perfected by numerical analysis, and the distribu-tion law of water pressure field, displacement field and the stress field of the tunnel were in-vestigated. Based on the calculated results, the safety distance between the water source and the tunnel was extracted, and the influence degree of water gushing on the tunnel was divided, which provides the safety evaluation index for the loess tunnel in local-high-pressure water environ-ment.