浅表层软黏土不排水强度的原位测试方法  

In-situ testing method for undrained shear strength in shallow soft clays

作　　者：郭绍曾[1] 刘润[1] 张雪东 GUO Shao-zeng;LIU Run;ZHANG Xue-dong(State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072,China;China Institute of Water Resources and Hydropower Research,Beijing 100010,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072 [2]中国水利水电研究院岩土工程研究所,北京100010

出　　处：《岩土工程学报》2019年第2期303-310,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家重点基础研究发展计划("973"计划)项目(2014CB046802);水利工程仿真与安全国家重点实验室开放基金项目(HESS-1516)

摘　　要：提出了一种新的条形探头,该探头不仅具有全流动探头的优点,并缩小了已有的全流动探头的端部效应,可较好地测定浅表层软黏土的不排水强度。开展了条形探头浅层贯入室内模型试验,分析了探头贯入过程中土体的运动规律。应用数值方法进一步研究了探头贯入过程中的土体破坏模式,建立了深、浅破坏模式转换深度的下限解。依据试验结果和土体破坏形态,提出了条形探头在浅层软土中贯入时的虚拟应力场和机动场,基于极限分析理论求解了土体贯入阻力与土体强度关系的上下限解。根据试验得到的贯入阻力计算出土体强度的上下限值,十字板强度均位于极限分析上下限解之间,证明了条形探头探测浅表层软土强度的适用性。A new type penetrometer named strip penetrometer is proposed.The strip penetrometer has the same advantages of other full-flow penetrometers with less end effect,and it is also applicable to detecting undrained strength of shallow soil.The shallow penetration test results of strip penetrometer are introduced.The motion modes of soils in the tests are analyzed.The lower bound solution at the shallow-deep transforming depth is established based on the numerical simulation.The virtual stress fields and kinematically admissible velocities are proposed as the penetrometer penetrates shallowly,and the lower and upper bounds are solved.The upper and lower limit strengths of soil test are compared with the vane shear strength.The results of the strip penetrometer fit well with the test ones.

关 键 词：条形探头 土体破坏模式 室内试验 极限分析 

分 类 号：TU413.5[建筑科学—岩土工程]