双向地震作用下崩塌堆积体边坡动力模糊可靠性分析

Dynamic fuzzy reliability analysis of collapse accumulation slopes under bidirectional earthquakes

考虑崩塌堆积体边坡岩土体参数随机性和模糊性,以及地震力双向性,建立一种边坡地震动力模糊可靠度计算方法,针对竖向地震力对崩塌堆积体边坡稳定可靠性的影响进行进一步研究。首先,选用动力有限元时程分析法计算出双向地震工况下崩塌堆积体边坡的响应特征,并运用模糊理论对强度参数进行模糊性处理;然后,根据Mohr-Coulumb强度准则构建边坡安全系数与可靠度的时程计算模型;最后,采用边坡地震可靠性评价新方法,通过MATLAB编写相应程序,实现计算和分析结果的快速输出。案例结果表明:新方法计算结果更加合理,对工程而言也更加安全;竖向地震作用均对崩塌堆积体边坡整体可靠性存在影响,但影响程度需根据工程实际情况进行分析。在算例工况下,竖向地震对崩塌堆积体边坡的可靠性影响很小,仅使得可靠度降低3.55%,因此,可仅考虑水平地震的影响。

A dynamic fuzzy analysis method for the seismic reliability of collapse accumulation slopes was established,considering the randomness and fuzziness of parameters for rock and soil in collapse accumulation slopes and the excitation of bidirectional earthquakes.Furthermore,the influence of vertical earthquake excitation on the reliability of the collapse accumulation slope was analyzed.First,the dynamic time-history analysis of FEM was used to calculate the dynamic response of collapse accumulation slope under bidirectional earthquakes,and the strength parameters of rock and soil mass were processed using fuzzy theory.Based on the Mohr-Coulomb strength criterion,the time-history calculation model for the safety factor and reliability of the slope under an earthquake was then established.Finally,a new method for evaluating the seismic reliability of slope was adopted,and the corresponding program was compiled by MATLAB to realize the rapid output of calculation and analysis results.The calculation results of the proposed method are reasonable and safe for engineering.The vertical earthquake has an impact on the reliability of the collapse accumulation slope,but the degree of impact must be analyzed in accordance with the actual situation.For the working condition of the example,the vertical earthquake slightly influences the reliability of the collapse accumulation slope,which only reduces the reliability by 3.55%.Therefore,the influence of a vertical earthquake can be overlooked in this example,and only the influence of a horizontal earthquake should be considered.