乌东德拱坝坝肩三维抗滑稳定分析

 基于非线性有限元分析，采用三维有限差分程序FLAC3D，对乌东德拱坝联合坝肩岩体进行三维弹塑性数值模拟。由拱座岩体内不连续裂隙产状确定9个可能滑动楔块。将有限元计算的应力值通过插值转移到楔块滑面上，以滑面内短小裂隙建议连通率为依据折减滑面抗剪强度，采用三维矢量和法计算楔块安全系数。弹塑性计算结果表明，坝肩岩体在荷载条件下位移、应力分布基本对称河谷，但是受近坝断层F15，f42及K25岩溶系统影响，右坝肩受影响范围略大于左岸。正常蓄水条件下9个楔块具有较高的安全裕度，温升荷载导致大部分楔块稳定性降低，温降荷载主要对右坝肩稳定不利。地震荷载条件下，所有楔块稳定性大幅降低，平均降低30%，最大降低53.9%，坝肩岩体整体仍能保持稳定。

THREE-DIMENSIONAL STABILITY ANALYSIS OF DAM ABUTMENT OF WUDONGDE ARCH DAM

The fast Lagrangian analysis of continua in three dimensions(FLAC3D) was adopted based on nonlinear finite element analysis,to develop three-dimensional elastoplastic numerical simulation of Wudongde arch dam.Nine possible sliding blocks were determined through the altitude of discrete fracture inside the arch dam rock mass.The calculation method of the experiment was to apply the finite element stress value to the sliding face through interpolation,discount sliding face shearing strength based on the altitude of discrete fracture inside the sliding face,and compute the factor of safety through 3D vector sum method.The results indicate that the stress and displacement distributions are basically symmetrical to the river valley.However,affected by the faults F15,f42and the K25karst system,there is a slightly larger area affected in right abutment than that in left abutment.The results also show that the nine sliding blocks have high margin of safety under normal impounding level;temperature rise load causes the stability reduction of a majority of wedge blocks,while temperature drop load mainly affects the stability of right abutment negatively.Under the seismic load,the stabilities of all the wedge blocks reduce largely with an average reduction of 30% and the maximum reduction of 53.9%.However,the global abutments rock mass can still remain stable under such situation.