强风化云母石英片岩原位直剪试验研究  

In-situ direct shear tests of strongly weathered mica-quartz schist

作　　者：谭儒蛟 刘国权 李光明 张启斌 吕耀志 Tan Rujiao;Liu Guoquan;Li Guangming;Zhang Qibin;Lyu Yaozhi(Tianjin Municipal Engineering Design&Research Institute Company,Tianjin 300051,China)

机构地区：[1]天津市政工程设计研究总院有限公司,天津300051

出　　处：《工程勘察》2024年第8期20-25,共6页Geotechnical Investigation & Surveying

基　　金：天津市科技支撑重点项目(20YFZCSN01080).

摘　　要：强风化片岩难以采取原状试样开展室内试验获取岩体力学强度参数,原位直剪试验是获取强风化片岩抗剪强度参数的可靠途径。原位直剪试验研究表明,强风化片岩整体呈弹塑性破坏特征,在抗剪断强度达到峰值后,剪切位移急剧增大,剪应力未出现陡降,即残余强度效应不明显。同时,强风化片岩抗剪断内摩擦角呈显著的各向异性,随预设剪切面与层理面夹角的增大而增大,当夹角为零即沿层理面剪切时内摩擦角值最小;强风化片岩的黏聚力与剪切方向相关性不明显,主要受岩体内石英、云母等矿物成分含量的高低影响。基于原位直剪试验成果,开展强风化片岩高边坡防护工程优化设计的成功实践表明,加大勘察成本投入,通过原位试验获取可靠的抗剪强度参数,可保证高边坡支护设计方案的安全性和经济性。It is difficult to obtain undisturbed samples of strongly weathered schist for laboratory testing,and in-situ direct shear test is the most reliable way to obtain shear strength parameters.In-situ direct shear tests show that the strongly weathered schist exhibits elastic-plastic failure characteristics as a whole.When the shear strength reaches the peak value,the shear displacement increases sharply,but the shear stress does not decrease significantly,that is to say,the residual strength effect is not obvious.At the same time,the internal friction angle of strongly weathered schist exhibits significant anisotropy,the internal friction angle increases with the increase of intersection angle between preset shearing surface and bedding plane.When the intersection angle is zero,shearing along bedding plane,the internal friction angle is the minimum.The correlation between the cohesion and shear direction of strongly weathered schist is not significant,and the cohesion mainly related to the content of mineral components such as quartz and mica in the rock mass.For the high slope engineering composed of strongly weathered rock,it is suggested to increase the investment of engineering survey cost,and obtain the shear strength parameters of strongly weathered rock through in-situ direct shear tests to ensure the safety and economy of high slope support design scheme.

关 键 词：强风化云母石英片岩 原位直剪试验 岩体强度 结构面强度 

分 类 号：TU443[建筑科学—岩土工程]