THREE-DIMENSIONAL TRANSIENT FLOW NUMERICAL SIMULATION OF GROUNDWATER SEEPAGE IN DAM SITE OF WUDONGDE HYDROPOWER STATION

According to the problem of leakage bypassing the dam in Wudongde hydropower station and the deficiency of the two-dimensional and quasi-three-dimensional steady flow models,on the basis of the sufficient analysis of geology and hydrogeology characteristics of dam site,a hydrogeology conceptual model is generated;a three-dimensional transient flow numerical simulation model is established,which is solved by the finite difference method and the preconditioned conjugate gradient method. Based on the simulation of the three-dimensional seepage fields under the three working conditions including natural state,normal water storage with impervious curtain and normal water storage without impervious curtain,according to the principle of water balance,the seepage quantities of various schemes in dry and wet season are calculated. The results show that the seepage quantity bypassing the dam on the right bank is about 5.7 times that of the left bank;compared with the system without anti-seepage treatment,the total seepage quantity can reduce by 72.98% after anti-seepage treatment;the seepage quantities bypassing right and left dam abutments and the dam foundation in wet season are less than those in dry season. It is shown that the convergence speed of the model is fast;and the stability of the model is good.