四寨水库高重力墩拱坝整体非线性分析和安全评价

Integral non-linear stability analysis and safety evaluation for high gravity pier-arch dam at Sizhai Reservoir

为评价高重力墩对四寨拱坝的应力变形和抗滑安全的影响,建立了拱坝重力墩地基系统的有限元数值模型,其中考虑重力墩基础、右岸夹层和拱坝重力墩等交界面的非线性相互作用,以及基岩材料的弹塑性变形行为。分别采用水压超载法和折减强度参数法对重力墩拱坝系统进行数值模拟,并基于建议的重力墩安全评价指标对系统整体稳定性进行判定。分析表明,采用水压超载法计算的整体安全超载系数为2.5～3.0,折减强度参数法计算的整体稳定强度储备系数为2.0～3.0。参考已有的拱坝整体稳定分析统计数据,该工程的整体稳定安全系数相对较低。

A finite element numerical model for arch dam-gravity pier-foundation system was established to evaluate the effect of high gravity piers on the stress, deformation and anti-sliding stability of Sizhai arch dam, taking the following factors into account, such as the possible elastoplastic deformation of foundation rocks and the nonlinear interaction between the interfaces of gravity pier -dam foundation, the joint surfaces beneath the right bank, and the interfaces of arch dam-gravity pier. The hydro-pressure overloading method and the strength reduction method were applied to numerical simulation of gravity pier-arch dam system, and the integral stability of the system was evaluated based on the suggested index for safety evaluation of the gravity pier. The result shows that the integral safety factor of the dam-pier-foundation system calculated by the over-loading method is 2.5-3.0, and the safety storage factor of the system by the strength reduction factor is about 2.0-3.0. The comparison of the calculated results with the statistical data of integral stability analysis obtained before shows that the integral safety factor of Sizhai arch dam is relatively low.