考虑库水特性的重力坝动水压力求解

Solution of hydrodynamic pressure on gravity dam with considering characteristics of impounded water

为了对重力坝坝面动水压力进行便捷求解,在比例边界有限元方法的框架下可仅对上游坝面进行离散,推导出在不同方向地震动激励下刚性坝面动水压力的求解方程以及边界条件,详细分析了竖向地震动激励对坝面动水压力的影响.数值算例结果表明,所提计算方法能得到精度较高的数值解且可大幅降低计算量,此外,库水特性(包括库水的可压缩性和库底的吸收作用)对坝面动水压力的影响较大,同时还发现了动水压力沿库水上游方向的衰减规律.

Abstract ： In order to conveniently solve the hydrodynamic pressure on the surface of gravity dam, only the dam surface in the upstream needs to be dispersed under the frame of scaled boundary finite element method. In addition, the solution equation and boundary condition for the hydrodynamic pressure on the rigid dam surface subjected to the earthquake excitation in different directions were derived. The effect of vertical earthquake excitation on the hydrodynamic pressure of dam surface was analyzed. The results of numerical examples show that the numerical solution with high accuracy can be obtained with the proposed approach, and the computation amount significantly reduces. Moreover, the characteristics of impounded water, including both compressibility of impounded water and absorption action of reservoir bed, have significant influence on the hydrodynamic pressure of dam surface. Meanwhile, the attenuation law of hydrodynamic pressure along the upstream direction of impounded water is also discovered. Key words： gravity dam; hydrodynamic method; rigid dam surface; dam-reservoir interaction pressure; absorption action; scaled boundary finite element attenuation law; semi-analytical solution ; two-dimension;