Simulation tests on structural deformation and seepage field of high-speed railway tunnels under drainage clogging

Based on 3D printing technology, a fine model for high-speed railway tunnel structure and drainage facilities is constructed, and a feasible simulation method for drainage clogging is put forward. Based on a typical disease case, a simulation test on drainage clogging is carried out, and under different conditions of drainage clogging and groundwater level, the seepage field (including drainage volume and external water pressure) and structural deformation are discussed. The results show that with the deepening of blockage, the drainage volume shows a slow downward trend and then a fast downward trend, and specifically, when the drainage pipe blockage is less than 50%, the tunnel drainage decreases slightly, and when the blockage is more than 50%, the tunnel drainage decreases sharply until no drainage occurs. The displacement of bottom structure uplift has the quantitative relation of "tunnel bottom > inner rail > outer rail", and with the increase of blockage degree, the uplift displacement slowly grows first and then fast grows. Affected by the reduction of drainage, the external water pressure of the structure gradually changes from "the maximum at the bottom, next at the crown and waist of the arch, and minimum at the foot of the wall" to the "hydrostatic pressure" distribution. The test results of displacement coincide well with the characteristics of field defects when the water head is 40 m and the drainage pipe is fully blocked, which verifies the feasibility and validity of the proposed simulation method. The research results may provide reference and guidance for prevention of pipe plugging and evaluation of similar defects of water-rich tunnels.