基于间接边界元方法的SH波倾斜入射下边坡动力响应特征  

Dynamic Response Analysis of Slope Rock Mass with Complex Shape Based on Indirect Boundary Element Method

作　　者：周剑 张路青[2,3] Zhou Jian;Zhang Luqing(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institutions of Earth Science,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]中国科学院地质与地球物理研究所,中国科学院页岩气与地质工程重点实验室,北京100029 [3]中国科学院地球科学研究院,北京100029

出　　处：《地球科学》2022年第12期4350-4361,共12页Earth Science

基　　金：国家重点研发计划项目(No.2019YFC1509703);国家自然科学基金资助项目(No.41972287).

摘　　要：地震作用下山体边坡的动力响应规律与地震波入射角度显著相关,本文基于间接边界元方法研究SH波倾斜入射下边坡的动力响应特征.基于间接边界元理论研发了用于边坡岩体动力响应分析的边界元程序,通过计算平直裂隙对弹性波的反射及散射波波场对程序进行验证,并详细探讨了不同类型的边坡在各种入射角度的应力波作用下的响应特性.SH波铅直向入射时,半圆形凹陷地形的谷肩位置地震动振幅最小,而半圆形凸起地形的最高点位置振幅最大,单面坡的坡肩位置地震动最大,楔形凸起地形的坡顶地震动最强烈;当SH波入射角增大,各类边坡的最大地震动力响应位置也有所偏移,地震放大系数亦随之变化;以樟木镇边坡为实例揭示了复杂形态边坡岩体中的局部凸起对地震动的放大作用.研究结果表明,边坡微地形特征对地震动力响应影响非常大,凸起山体坡顶的动力放大效应最为显著;同一边坡在不同入射角地震波作用下产生的动力放大系数以及发生的位置不同.本文的研究结果对评价坡体稳定性和边坡工程抗震防设等具有重要的指导意义.The dynamic response of slope under earthquake is significantly related to the incident angle of seismic waves.Based on the indirect boundary element method(BEM),the dynamic response characteristics of slopes with oblique incident SH waves are studied in this paper.First of all,based on indirect boundary element theory,a BEM program for dynamic response analysis of rock slope has been developed and validated by calculating the elastic reflection and scattered wave at an opened flat fracture.Then,the boundary element numerical simulation is used to analyze the response characteristics of different slopes under stress wave loading with various incident angles in detail.If the SH waves incident straightly,the seismic amplitude at the shoulder of the semi-circular depression terrain was the smallest,while the seismic amplitude at the highest point of the semi-circular convex terrain was the largest.The immense vibration appears at the shoulder of the single-slope,and the vibration at the top of the wedge convex terrain was the strongest.With the incidence angle of SH wave increasing,the positions with the maximum seismic dynamic response of all kinds of slopes also shift,and the seismic amplification coefficient changes accordingly.In addition,a slope in Zhangmu Town is taken as an example to reveal the amplification effect of local bulges on ground motion in rock slops with complex shapes.The main conclusions can be summarized.The slope microtopography greatly influences the seismic dynamic response,and the dynamic amplification effect is the most significant at the top of the raised mountain slope.The dynamic amplification coefficient and location of the same slope under the action of seismic waves at different incidence angles are different.The results of this research have important directive significance for evaluating slope stability and seismic design.

关 键 词：边坡动力响应 间接边界元法 地震波传播 坡形 数值模拟 工程地质 

分 类 号：P64[天文地球—地质矿产勘探]