Study on the external water pressure of deep-lying tunnel in Jinping hydropower station

To a deep-lying tunnel in the area with high groundwater table, external water pressure is the main load and the determination of the external water pressure is the important problem the design and the construction of the tunnel. Therefore, it is essential to study the external water pressure of the deep-lying tunnel in Jinping cascade 2 hydropower station. In this paper the authors have studied the problem of the water pressure by means of the finite element daring method of analyze on the seepage field with rainfall. A new water-controlling idea that is preventing the subsurface water complemented with draining it has been put forward Jinping tunnel. By high-pressure concretion grouting, the subsurface water can be prevented, and the surrounding rock in the grouting zone and the supporting structures can be combined to bear loads.