Study on the seepage characteristics of deep buried tunnels under variable high-pressure water heads.

Well-connected seepage channels are the key components of tunnel water inrush. To study the trends of the pore water pressure in the rock mass in a seepage channel, the physical experiment and corresponding numerical model were established. First, in the seepage experiment under excavation disturbance, the propagation rate of the high-pressure water source and the growth rate of the pore water pressure in the rock mass were analyzed by considering the different water pressures. Second, under the same model size, parameters, and working conditions, the finite element method was used to simulate the seepage process of water in the rock mass. From the microlevel, the evolution process of the pore water pressure isosurface was obtained. The results showed that the pressure water head is positively correlated with the pore water pressure in the rock mass, which displays multiple approximate relationships. Moreover, when the water pressure is high, excavation disturbance can significantly increase the pore water pressure in the rock mass. The disturbance caused by the first excavation is larger than the subsequent excavations. In addition, the research results were compared with previous results. Reasonable agreements that would provide a reference for the conditions of high water-pressure disasters in deep buried tunnel construction were obtained. [ABSTRACT FROM AUTHOR]