不同角度基覆面上土石混合体变形试验研究及对滑坡演化的启示  

Effect of bedrock slope angle on deformation and failure of overlying rock-soil mixture:Insight into the evolution of landslides

作　　者：孙永帅 胡瑞林[2] SUN Yongshuai;HU Ruilin(College of Water Resources and Civil Engineering,China Agricultural University,Beijing 100083,China;Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]中国农业大学水利与土木工程学院,北京100083 [2]中国科学院地质与地球物理研究所页岩气与地质工程重点实验室,北京100029

出　　处：《地学前缘》2023年第3期494-504,共11页Earth Science Frontiers

基　　金：北京市自然科学基金项目(8214060);国家自然科学基金项目(42107164)。

摘　　要：由于基覆面的角度会对土石混合体滑坡的变形破坏产生重要影响,研究土石混合体滑坡的基覆面角度作用规律对于全面评价土石混合体滑坡的稳定性具有重要意义,然而目前基覆面角度研究定量化不足。为了研究在不同角度基覆面情况下土石混合体的变形破坏,利用设计的大型推剪仪对不同角度基覆面情况下的土石混合体变形破坏开展试验研究。结果表明:随着基覆面角度的增加,剪切面与基覆面的夹角增大,剪切面与基覆面的距离也会增加。当基覆面角度为25°时,位于剪切破裂带的土石混合体整体运移程度最好,当基覆面角度为45°时,位于剪切破裂带的土石混合体破裂程度最严重,土石混合体的整体运移程度最差,滑裂带治理难度最大。随着基覆面角度的增加,最大剪应力先增大后减小,中间出现临界作用角度(为45°),此时土石混合体变形破坏过程中的最大剪应力达到最大,孔隙水压力变化值与土压力变化值达到峰值所需要时间最长。本研究阐明了不同角度基覆面上土石混合体的强度及变形特征,揭示基覆面角度对土石混合体强度及变形破坏的作用机理,并确定了土石混合体与基覆面作用的临界作用角度,为今后评价基于土石混合体基覆面角度控制作用的滑坡等地质灾害的稳定性提供了一定的理论依据。The slope angle of bedrock surface plays an important role in deformation and failure of the overlying rock-soil mixture(debris).Therefore,it is of great importance to quantify the effect of bedrock slope on the evolution of landslides in order to obtain a comprehensive evaluation of the mechanical behavior and stability of landslides;however,such quantitative studies are currently lacking.To address this gap we carried out an experimental study on deformation and failure of rock-soil mixture under different slope angles of the underlying bedrock using a home-built large size push-shear apparatus.The results show that with increasing slope angle the included angle between the shearing and bedrock surfaces increases,and so does the distance between the two surfaces.At 25°inclination the overall movement of the rock-soil mixture in the shear zone is most stable;whereas at 45°inclination occurs the most serious debris rupture in the shear zone while the overall movement of debris is most unstable,and the slip zone is most difficult to manage.With increasing slope angle,the maximum shear stress first increases and then starts to decrease at 45°inclination—at this point,the maximum shear stress reaches maximum in the deformation process,and the peaking time of pore-water/soil pressure changes(from their initial values)reach maximum as well.The results and parameters obtained in this study provide a reference basis for evaluating landslide stability and other geological hazards based on the determination of bedrock slope.

关 键 词：滑坡 土石混合体 基覆面 大型推剪试验 不同角度 变形破坏 

分 类 号：P694[天文地球—地质学] TU43[建筑科学—岩土工程]