水平和竖向地震作用下顺层岩质边坡动力可靠性分析

摘要

As the traditional seismic reliability analysis of bedding rock slopes usually ignores the dynamic characteristics of earthquake and the existing seismic time-history analysis method is time-consuming and laborious,a dynamic reliability analysis method for bedding rock slopes considering the seismic dynamic characteristics and the randomness of strength parameters is proposed.A simplified calculation method for seismic response of bedding rock slopes is developed based on the Wilson-θ method and the Matlab/Simulink toolbox.The dynamic reliability of slopes is then calculated by the Monte Carlo method,and the evaluation index of overall minimum mean dynamic reliability is presented to assess the overall seismic reliability of slopes.Furthermore,the effects of superposition modes of horizontal and vertical earthquake actions on the reliability of bedding rock slopes are analyzed.Analyses of examples show that this proposed method for seismic response possesses high accuracy and efficiency.The reliability analysis method proposed in this work underestimates the seismic reliability of slope.Compared to the horizontal earthquake action,the effect of vertical earthquake action on the reliability of bedding rock slopes is also remarkable.It is also observed that the commonly used superposition mode of peak values of horizontal and vertical earthquake actions is incapable of fully reflecting the superposition effect of the maximum actions of bidirectional earthquake,but the application of the superposition mode is generally safer.%由于传统顺层岩质边坡地震可靠性分析往往是基于拟静力法,忽略了地震的动力特性,而基于数值模拟软件的地震时程分析法虽能考虑地震的动态性,却相对费时费力,该文同时考虑了地震的动力特性和强度参数随机性,提出顺层岩质边坡动力可靠性分析方法.运用Wilson-θ法和Matlab/Simulink工具建立了顺层岩质边坡地震响应简化计算方法.根据响应结果,运用Monte Carlo法计算了边坡的动力可靠度,并提出采用整体最小平均可靠度来评价边坡的地震整体可靠性.在此基础上,进一步分析了水平和竖向地震作用的叠加模式对顺层岩质边坡可靠性的影响.算例分析表明,提出的地震响应简化计算方法具有较高的计算精度和效率.该文可靠度分析方法低估了边坡的地震可靠性.与水平地震作用相比,竖向地震作用对顺层岩质边坡可靠性的影响也很明显.常用的水平和竖向地震作用的峰值叠加模式并不能充分地体现出双向地震的最大作用叠加效果,而采用双向地震的最大作用叠加模式更偏于工程安全.