黄土原位钻孔剪切试验研究  

Research of In-situ Borehole Shear Test of Loess

作　　者：黄晓维 刘子君 杨振荣 郑建国 Huang Xiaowei;Liu Zijun;Yang Zhenrong;Zheng Jianguo(China Jikan Institute of Engineering Investigation and Design Co.,Ltd.,Xi’an 710043,Shaanxi,China;China United Northwest Institute for Engineer Design&Research Co.,Ltd.,Xi’an 710077,Shaanxi,China)

机构地区：[1]机械工业勘察设计研究院有限公司,陕西西安710043 [2]中联西北工程设计研究院有限公司,陕西西安710077

出　　处：《岩土工程技术》2023年第4期465-469,共5页Geotechnical Engineering Technique

摘　　要：准确获得黄土原位土体抗剪强度参数对黄土工程至关重要。将钻孔剪切试验应用于西安某黄土滑坡原位土体抗剪强度参数测试,提出了黄土场地中适宜的成孔方法,在原Iowa钻孔剪切仪基础上加装微型位移测量系统和剪切力测量系统,精确测量法向位移与剪切应力,并将钻孔剪切试验结果与室内直剪试验结果进行了对比。结果表明,改进后的设备测试更加可视化、可控化;试验阶段法向压力–位移分布近似在一条直线上,土体处于似弹性变形阶段;首级法向压力固结时间为10 min,后续每级压力固结时间为5 min,满足试验要求并能保证试验成功率;与室内直剪试验相比,钻孔剪切试验测得的内摩擦角平均大40.8%,黏聚力平均小12.7%。钻孔剪切试验数据之间相关性较好,测试效果良好,可为今后黄土原位土体抗剪强度参数测试提供借鉴与指导。It is very important to accurately obtain the in-situ shear strength parameters of loess for loess engineering.In this study,borehole shear test(BST)was applied to test the shear strength parameters of loess on a loess landslide in Xi'an.The suitable drilling method in loess site was proposed,and a micro displacement-shear strength measurement system was added on the basis of the original Iowa borehole shear test to accurately measure the normal displacement and shear stress.The results of BST and direct shear test were compared.The results show that the improved equipment is more visible and controllable;the normal stress is proportional to displacement,which indicates that the soil is in the stage of quasi elastic deformation.To ensure the reliability of the results,the time for consolidation under the first stage of normal stress needs 10 min while 5 min meet the requirement in the subsequent stages.Compared with the direct shear test,the internal friction angle measured is larger for 40.8%on average while cohesion is 12.7%smaller.The borehole shear test shows a good performance on the test of the shear strength parameters of loess in-situ.

关 键 词：钻孔剪切试验 法向压力 固结时间 黄土 

分 类 号：TU413[建筑科学—岩土工程]