砂柱法制样及剪切速率对黏性粗料三轴试验的影响  

Influence of sample preparation by sand column method and shear rate on triaxial test ofcohesive coarse-grained soil

作　　者：张富臣 王鹏程[1] 张庆建[1] 李玉贵[1] 于磊 ZHANG Fuchen;WANG Pengcheng;ZHANG Qingjian;LI Yugui;YU Lei(China Water Resources Beifang Investigation,Design and Research Co.,Ltd.,Tianjin 300222,China)

机构地区：[1]中水北方勘测设计研究有限责任公司,天津300222

出　　处：《人民长江》2024年第1期223-228,235,共7页Yangtze River

基　　金：中水北方勘测设计研究有限责任公司课题基金项目(K2022-134)。

摘　　要：对砂柱法和常规方法制备的黏性粗粒土三轴试样进行饱和试验,对比其饱和效果,同时为论证砂柱对土体排水效果、应力-应变关系和强度特性的影响,开展砂柱法试样和常规试样在不同剪切速率下的三轴CD剪试验,并讨论剪切速率对试验的影响。试验结果表明:砂柱法配合反压饱和6 h,试样基本饱水均匀;常规试样的速率敏感度较高,随着剪切速率的增大,强度指标φd减小、Cd增大,同一围压下,峰值偏应力减小;体应变εv与剪切速率呈反比,且围压越大,越不利于土体排水,峰值偏应力减小的幅度越大;剪切速率与Ei呈反比,与Bi成正比,邓肯-张模型参数Rf、k、n、D和F值随剪切速率的增大而减小;砂柱法制备的试样速率敏感度较低,且砂柱法试样在0.3 mm/min剪切速率下具有同常规试样0.03 mm/min剪切速率下相似的三轴应力-应变特征;该方法获取了相近的CD剪强度指标和邓肯张模型参数,同时缩短了试验在饱和-固结-剪切3个阶段的用时,大幅提高了试验效率,具有良好的经济效益。研究结果可为与黏性粗粒土三轴试验相关的实践和研究工作提供参考。The saturation tests were carried out on triaxial samples of cohesive coarse-grained soil prepared by the sand column method and conventional method,and the saturation effects were compared.To demonstrate the influence of sand column on soil drainage effect,stress-strain relationship and strength characteristics,CD shear tests of sand column method samples and conventional samples at different shear rates were carried out,as well as the influence of the shear rate on the test were discussed.The test results were as follows:after combining the sand column method with pressure saturation for 6 hours,the sample was basically saturated with water evenly.The rate sensitivity of conventional samples was high.With the increase of the shear rate,the strength indexφd decreased,C d increased,and under the same confining pressure,the peak deviatoric stress decreased.The volume strainεv was inversely proportional to the shear rate,and the greater the confining pressure,the less conducive it was to soil drainage,and the greater the decrease of the peak deviatoric stress.The shear rate was inversely proportional to E i and directly proportional to B i,and the values of the Duncan-Chang model parameters R f,k,n,D and F decreased with the increase of the shear rate.The rate sensitivity of the sample prepared using the sand column method was low.The sample prepared using the sand column method at 0.3 mm/min shear rate had similar triaxial stress-strain characteristics,CD shear strength index and Duncan-Chang model parameters to the conventional sample at 0.03 mm/min shear rate.The test time in the three stages of saturation-consolidation-shearing was shortened,so the test efficiency was greatly improved.The research results can provide a reference for the practice and research work related to the cohesive coarse-grained soil triaxial test.

关 键 词：黏性粗粒土 剪切速率 CD剪 砂柱法 三轴试验 

分 类 号：TV16[水利工程]