摘要
利用DZY-Z-2型真三轴试验仪,对德州地区粉质黏土进行不同围压和中主应力系数b条件下的不排水剪切试验,研究了应力和孔压曲线变化规律、抗剪强度、主应变及试样破坏.试验结果表明:应力和孔压曲线随应变增大而增大并趋于稳定;相同围压下随b值增大曲线初始斜率先增大后减小,b=0.75时峰值应力和峰值孔压最大;随b值增大,土的黏聚力随之增大;内摩擦角先增大后减小,b=0.5时内摩擦角最大;相同围压下随b值增大,小主应变曲线斜率增大,中主应变由负值变为正值;相同b值时随围压的增大,小主应变和中主应变曲线斜率都减小;b=0时,土样在小主应力和中主应力作用面同时发生膨胀;b=0.25~1时,在中主应力作用面上出现两个对立的锥形.通过研究,对不同围压和中主应力系数条件下粉质黏土的力学性质有了规律性认识,围压和中主应力系数对土的抗剪性能影响较大.
Using DZY-Z-2 true triaxial apparatus,the shear tests of undrained Conditions were conducted on silty clay of Dezhou of Shandong Province under different confining pressures and intermediate principal stress ratio b,the variation of stress and pore pressure curves,shear strength,principal strain and sample deformation were studied.The results show that:(1)The stress and pore pressure curves increase and tend to be stable with the increase of strain;under the same confining pressure,the initial slope of the curve increases first and then decrease with the increase of b,the peak stress and peak pore pressure reach the maximum when b=0.75.(2)the cohesion of soil increases with the increase of b;the angle of internal friction increases first and then decreases with the increase of b,and reaches the maximum when b=0.5.(3)At the same confining pressure,the slope of minor principal strain curve increases with the increase of b,intermediate principal strain changes from negative value to positive value;with the increase of confining pressure at the same b,the slope of minor and intermediate principal strain curves decreases.(4)When b=0,dilatation occurs simultaneously on the minor and intermediate principal stress surfaces;when b=0.25~1,two opposite conical shapes appear on the surface of the intermediate principal stress.The mechanical properties of silty clay are understood regularly,the confining pressure and intermediate principal stress ratio have great influence on the shear properties of silty clay.
作者
杨康康
柴寿喜
王沛
严江胜
刘琦
YANG Kangkang;CHAI Shouxi;WANG Pei;YAN Jiangsheng;LIU Qi(Tianjin Chengjian University,Tianjin 300384,China;Tianjin Tai Architecture Design Institute,Tianjin 300000,China)
出处
《天津城建大学学报》
CAS
2021年第4期244-249,共6页
Journal of Tianjin Chengjian University
基金
天津市科技支撑重点项目(19YFZCSF00820)。
关键词
真三轴试验
中主应力系数
应力-应变
抗剪强度
试样破坏形态
true triaxial shear test
intermediate principal stress ratio
stress-strain
shear strength
sample deformation
