大光包滑坡滑带碎裂岩体原位钻孔剪切试验研究

In-situ borehole shear tests on cataclastic rock mass of Daguangbao landslide

安县大光包滑坡是汶川地震触发的最大规模滑坡,滑坡南侧暴露长约1.8 km顺层滑带,其岩体高度碎裂化,引起广泛关注。为准确评价滑带碎裂岩体的强度参数,笔者在前人研究的基础上开展了细致的野外调查工作,采用法国Phicometre岩土两用原位钻孔剪切试验仪对大光包滑坡滑带碎裂岩体进行了原位剪切试验。将试验结果与Hoek–Brown岩体强度准则估值和基于工程地质类比法的力学参数建议值进行了对比分析。基于以上研究,提出了大光包滑坡南侧顺层滑带碎裂岩体力学参数建议值:内聚力为245~480 k Pa,内摩擦角为25.0°~26.5°。

Daguangbao landslide is the largest landslide triggered by the Wenchuan earthquake. The exposed sliding zone with a length of 1.8 km and highly ruptured rock mass is located at the south side of the landslide, which has attracted great attention across the world. To evaluate the strength parameters of cataclastic rock mass in the sliding zone accurately, a detailed field survey work is carried out on the basis of previous researches by using a France Phicometre dual-purpose geotechnical in-situ borehole shear tester to investigate the cataclastic rock mass in Daguangbao landslide slip zone. A comparative analysis among the test results, the values of Hoek-Brown strength criterion and the mechanical parameter values based on the engineering geologic analogy method is performed. Finally, the mechanical parameter values of the rock mass of the Daguangbao landslide of the south side are proposed： its cohesion is from 245 kPa to 480 kPa, and its internal friction angle is from 25.0° to 26.5° .