考虑堆石料空间变异性的土石坝坝坡地震稳定性随机有限元分析

Seismic Slope Stability Analysis of Earth-Rockfill Dams Considering Spatial Variability of Rockfill Materials via Random Finite Element Method

摘要:

本文探讨了筑坝堆石料的空间变异性对土石坝坝坡动力稳定性的影响。以新疆某在建高面板堆石坝为例，在蒙特卡洛法的框架下，采用基于局部平均细分法的随机有限元法模拟考虑筑坝堆石料空间变异性时土石坝的地震响应及坝坡滑移情况，通过对比随机有限元法和常规确定性有限元法的计算结果，提出：在地震动作用下，考虑筑坝材料空间变异性时，坝坡滑动体的数量、规模以及滑移量和滑动历时都有不同程度的增大，因而坝坡整体危险程度显著高于不考虑材料空间变异性的情况。坝坡各项动力安全性指标对筑坝材料空间变异性非常敏感；因而，考虑筑坝材料空间变异性时，各项安全性指标的离散性较大。

Abstract:

The influence of spatial variability of rockfill materials on the dynamic stability of dam slope of rockfill dams was studied. Under the framework of Monte Carlo method, the random finite element method (RFEM) based on the local average subdivision method was adopted to simulate the seismic response and analyze the slope stability of a high concrete face rockfill dam in Xinjiang, China. By comparing the calculation results using the RFEM and conventional deterministic finite element method, it is determined that (1) when the spatial variability of the rockfill materials is considered, the number and dimension of sliding bodies, together with sliding movements and duration increased; therefore, the overall risk of the dam slope is significantly higher than that when the spatial variability of rockfill materials is not considered and (2) the dynamic safety indexes of dam slope are sensitive to the spatial variability of rockfill materials and show high degree of discretion consequently.