大岗山拱坝-地基体系整体抗震安全性研究

Study on integral seismic safety of Dagangshan Arch dam-foundation system

基于高拱坝-地基整体抗震安全评价体系,对设计地震动峰值加速度达0.5565g的大岗山拱坝-地基体系的地震响应进行数值分析,并分别对其在不同地震超载倍数和不同基岩控制性滑裂面抗剪强度降低倍数下的安全性和破坏机理进行研究,以寻求坝体控制性位移或与位移相关的变量随安全系数变化曲线的拐点作为整体失稳判断准则,进一步明确了具体实施方法,并对其整体抗震安全性作出评价。

Based on the integral seismic safety concept of clam-foundation system for arch dam,a corresponding analytical technique using FEM was developed.In this paper,the seismic safety of Dagangshan Arch Dam subjected to a design peak ground acceleration of 0.557 5g resulted in seismic overloading and shear strength reduction of the slide surfaces in the wedges are investigated respectively.In the numerical model,dam-reservoir-foundation interaction and nonlinear contact between contraction joints,dam-foundation interface as well as slide surfaces in abutment wedges are taken into account.Both dam body and critical abutment wedge are treated as an integral system and the system safety are determined by one single safety criterion,defined as the point of inflection of the relationship curve between dam displacement and seismic overloading factor or shear strength reduction factor.