考虑变形协调的地震作用下反倾岩质边坡弯曲倾倒稳定性分析方法  

Analytical method for flexural toppling failure of anti-dip rock slopes under seismic loads considering deformation coordination

作　　者：王润清 陈从新[1,2] 郑允 邵勇[1,2] 吴润富 WANG Runqing;CHEN Congxin;ZHENG Yun;SHAO Yong;WU Runfu(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang,Jiangxi 330013,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]华东交通大学土木工程学院,江西南昌330013

出　　处：《岩石力学与工程学报》2024年第1期146-156,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(12072358);中国科学院青年创新促进会(2022333);武汉市知识创新专项——基础研究项目(2022010801010161)。

摘　　要：我国西南地区高陡反倾岩质边坡广泛分布,坡体深部折断贯通容易形成规模巨大的滑坡,而地震是诱发反倾岩质边坡失稳破坏的重要外部因素。为分析地震作用下反倾岩质边坡的稳定性,以相邻岩层为基本力学分析单元,将其视为自由变形或协调变形的叠合悬臂梁,提出2种变形模式的判别条件。在此基础上,提出地震作用下反倾岩质边坡弯曲倾倒破坏力学模型,建立各岩层自由变形和协调变形的力学平衡方程,给出划分岩层变形类型的计算方法和边坡整体稳定性判别方法,并基于Matlab实现了地震作用下反倾岩质边坡弯曲倾倒分析的程序化。通过与不同地震影响系数下边坡UDEC模拟结果对比发现,理论计算和数值模拟得到的边坡安全系数相差最大不超过16%,自由变形区和协调变形区范围基本吻合,验证了所提方法的正确性。采用理论方法进行参数分析发现:岩层倾角对地震作用的影响显著,在相同地震影响系数下,边坡安全系数的降低幅度随着岩层倾角的增加而增大,而边坡坡度和岩层厚度对地震作用影响较小。研究结果对地震高危区域反倾岩质边坡失稳破坏的防治具有指导意义。High and steep anti-dip rock slopes are widely distributed in southwest China and rock layers in these slopes are easy to fracture at great depths,resulting in large scale landslides.Earthquakes are important external factors,inducing the toppling failure of anti-dip rock slopes.To analyze the stability of anti-dip rock slopes under seismic loads,adjacent rock layers are taken as the basic mechanical analysis unit,and regarded as cantilever beams with free or coordinated deformation.The discrimination conditions for two deformation modes are proposed.On this basis,a mechanical model for the flexural toppling failure of anti-dip rock slopes under seismic loads was proposed,and mechanical equilibrium equations for rock layers in the free or coordinated deformation zones were established.The calculation method for dividing rock layer deformation modes and the overall stability judgment method of the slope were provided.Based on MATLAB,the programming of flexural toppling analysis of anti-dip rock slopes under seismic loads was achieved.By comparing the UDEC numerical results of slopes under different earthquake impact coefficients,it was found that the maximum difference in slope safety factor between theoretical calculation and numerical simulation does not exceed 16%,and the range of free deformation zone and coordinated deformation zone is basically consistent,which verifies the correctness of the method proposed in this article.Parameter analysis found that the inclination angle of rock layers has a significant impact on seismic action,Under the same seismic impact coefficient,the reduction amplitude of the slope safety coefficient increases with the increase of inclination angle of rock layers.while the slope angle and rock layer thickness have a relatively small impact on seismic action.The study is helpful to prevent and control the failure of such rock slopes in seismic highrisk areas.

关 键 词：边坡工程 弯曲倾倒 地震作用 变形协调 分析方法 

分 类 号：P642[天文地球—工程地质学]