重力坝在校核地震工况下核算方法的建议

Evaluation Methods for Gravity Dams under MCE Load

水电规计[2008]24号文《水工工程防震抗震研究设计及专题报告编制暂行规定》明确提出,对于重要大坝,应进行校核地震工况下的抗震安全复核,但未明确具体的抗震安全复核方法和评价准则。从校核地震工况的基本概念出发,对重力坝在校核地震工况下的核算方法提出了建议:校核地震工况的核心是"不溃坝"的复核,不应把着眼点放在强度校核上,而应重点研究重力坝的整体稳定性。可以从力学的基本概念,利用改进的材料力学动力法、非线性有限元方法、Newmark滑块位移法、DDA、离散元等非连续方法以及静、动力刚体极限方法,系统地对重力坝的整体稳定性进行复核。校核地震工况下的复核符合"基于性能的抗震设计"这一新的抗震设计理念,是大坝抗震设计发展的方向。

The safety evaluation for very important dams in China under MCE loads must be performed according to regulation newly announced after Wenchuan Earthquake. But no details are given for the evaluation methods. From the concept of seismic safety evaluation （SSE） for MCE, a primary evaluation method system is presented in this paper. For MCE, the strength of concrete and rock is not the key index of SSE. The focus of SSE is monolithic stability of dams to prevent the sudden collapse of dams during and after earthquake events. A system of SSE method can include： advanced nonlinear cantilever method, nonlinear finite element method, Newmark sliding block method, Discontinuous Deformation Analysis, Distinct element method and rigid body limit equilibrium method. The SSE for dams under MCE loads is a very import progress of performance-based seismic design（PBSD）for hydraulic structures in China.