砂柱法制样及剪切速率对黏性粗料三轴试验的影响OACSTPCD

The saturation tests were carried out on triaxial samples of cohesive coarse-grained soil prepared by the sand col-umn 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 basi-cally saturated with water evenly.The rate sensitivity of conventional samples was high.With the increase of the shear rate,the strength index φd decreased,Cd increased,and under the same confining pressure,the peak deviatoric stress decreased.The vol-ume strain εv 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 Ei and directly proportional to Bi,and the values of the Duncan-Chang model parameters Rf,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.