真三轴条件下原状黄土的强度与含水率的关系

摘要

The suction is difficult measure but the moisture content is easy to determine in practi-cal engineering.The study of the relationship between strength and water content of unsaturated intact loess is of important theoretical value in simulating the complex stress state of soil,with a series of isotropic consolidation and shear tests with different intermediate principal stress ratio b under constant water content performed on intact loess with various water contents by using un-saturated soil true tri-axial apparatus.The relationship between the strength and the water con-tent is studied.Results show that the shear strength of soil decreases with the increase of water content,and increases with the net confining pressure and the ratio b;the cohesion of unsaturated undisturbed loess has a linear decrease with the increase of water content,but the internal friction angle has little change with the change of water content;the internal friction angle decreasing with the increase of ratio b while the cohesion increases with the ratio b;the function expression between the cohesion and the friction angle under different ratio b is established.%在实际工程中，吸力的量测比较困难，而含水率容易确定，研究原状黄土的强度与含水率的关系，具有非常重要的理论价值。模拟土体的复杂受力状态，利用真三轴仪对不同含水率的非饱和原状黄土进行了常含水率的等向固结和不同中主应力参数 b 值的剪切试验，研究了非饱和原状黄土抗剪强度随含水率的变化规律。研究结果表明：土体的抗剪强度随着含水率的增大而减小，随着净围压和 b 值的增大而增大；土体的黏聚力随着含水率的增大而线性降低，而内摩擦角受含水率的影响不大；内摩擦角随着 b 值的增大而减小，而黏聚力随着 b 值的增大而增大；并建立了不同 b 值条件下黏聚力与含水率的函数表达式。