摘要
针对传统Iowa钻孔剪切仪的剪切探头提拉速率难以满足操作规范、试验曲线无法可视化等缺陷,对其剪切破坏装置、剪应力采集装置进行改进,加装剪切位移自动采集装置,并应用于散体状强风化粉砂岩的抗剪强度参数测试。结果表明:原位钻孔剪切试验获取的岩土平均抗剪强度参数为内摩擦角φ=25.72°,黏聚力c=13.27 kPa,试验的稳定性受散体状岩体结构松散破碎、风化裂隙大量发育的影响,剪切位移达2~3 mm后,岩体迅速发生剪切破坏,在线弹性变形阶段,剪应力迅速增大至峰值,随后发生持续波动。而同一场地的现场大型直剪试验结果为内摩擦角φ=28.06°,黏聚力c=16.11 kPa。两种试验结果较为接近,为改进原位钻孔剪切仪的有效性提供了基本验证。相较于现场大型直剪试验周期长、操作复杂、耗费大量人力和物力等缺陷,原位钻孔剪切试验更具性价比,钻孔剪切仪的改进具有较高的实际应用价值。
Aiming at the defects of the traditional Iowa borehole shear instrument,such as the shear probe lifting rate is difficult to meet the operation specification and the test curve cannot be visualized,the shear destructive device and shear stress collection device are improved,and the shear displacement automatic collection device is added.It is applied to the shear strength parameter tests of the bulk-like strongly weathered siltstone.The results show that:the average shear strength parameters of the rock and soil obtained from in-situ borehole shear tests are the internal friction angle φ=25.72°,the cohesion c=13.27 kPa.The stability of the tests is affected by the loose and broken structure of the bulk-like rock body and a large number of weathering fissures,and the shear displacements up to 2~3 mm are followed by the rapid occurrence of shear destruction of the rock body.At the linear elastic deformation stage,the shear stress rapidly increases to the peak value,and the subsequent continuous fluctuation occurs.The results of the on-site large-scale straight shear tests at the same site are the internal friction angle φ=28.06°,the cohesion c=16.11 kPa.The two test results are relatively close to each other,which provide a basic verification for the effectiveness of the improved in-situ drilling shear instrument.Compared with the defects of the on-site large-scale straight shear test,such as the long cycle time,complicated operation,and consuming a lot of manpower and material resources,the in-situ drilling shear test is more cost-effective,and the improvement of the drilling shear instrument has a high practical application value.
作者
卢忆晗
黄如发
杨志林
齐昌广
张智超
Lu Yihan;Huang Rufa;Yang Zhilin;Qi Changguang;Zhang Zhichao(School of Civil&Environmental Engineering and Geography Science,Ningbo University,Ningbo 315211,China;Fujian Province Construction Research Engineering Consulting Co.,Ltd.,Fuzhou 350108,China;Key Lab.of Geohazard Prevention of Hilly Mountains,Ministry of Natural Resources of China,Fujian Geological Engineering Survey Institute,Fuzhou 350002,China;Fujian Provincial Key Laboratory of Geological Hazards,Fuzhou 350002,China)
出处
《工程勘察》
2026年第2期16-22,共7页
Geotechnical Investigation & Surveying
基金
福建省杰出青年科学基金(2023J06039)
国家自然科学基金(41977259,U2005205,41972268).
关键词
抗剪强度参数
原位钻孔剪切试验
仪器改进
散体状强风化粉砂岩
shear strength parameters
in-situ borehole shear test
improved instrumentation
strongly weathered siltstone
