奥罗维尔土坝三维排水有效应力动力分析

3-D dynamic analysis of effective stress of Oroville earh dam

本文采用三维排水(考虑孔隙水压力扩散与消散)有效应力动力分析方法,研究了美国奥罗维尔(Oroville)土坝在7度地震作用下的动力反应。研究中将地震孔隙水压力与土坝的变形和团结紧密结合起来,将地震孔隙水压力引入皮奥(Blot)方程,用三维等参数有限元法求解变形和残余孔隙水压力,计算了地震动应力、动应变、加速度、残余孔隙水压力及其随时间的变化等。最后,用二维排水有效应力动力分析的结果与之比较。

Dynamic response of the Oroville Earth Dam in U. S. A. under an earthquake of intensity Ⅶ is investigated by using 3-D analysis of effective stress considering the diffusion and dissipation of seismic pore water pressure. In this investigation the earthquake induced pore water pressure is closely related with the deformation and consolidation of earth dam, thus the earthquake pore water pressure is introduced into the Biot' s equation, which is then solved by 3-D equiparametric FEM to obtain deformation and residual pore water pressure. The following items are computed: seismic dynamic stresses, dynamic strains, acceleration, residual pore water pressure and its variation with time, etc. Finally, the computed results are compared with those by 2-D dynamic analysis of effective stress.