饱和高岭土的部分排水剪切应力-应变特性

Stress-strain Behavior of Saturated Kaolin Sheared under Partially Drained Condition

为模拟实际工程中土体经常受到的固结和剪切同时作用(即部分排水剪切条件),基于三轴压缩试验方法,采用不同的轴向应变速率加载,并在剪切过程中始终打开排水阀的方式,开展了重塑饱和高岭土试样的部分排水剪切试验,分析了其在体变和孔压共同作用下的应力-应变特性。试验结果表明:部分排水剪切条件下所引起的孔压随着轴向应变位移加载速率的增加而增加,而抗剪强度却随着轴向应变位移加载速率的增加而减小,临界状态线并不依赖于剪切过程中的加载速率和排水条件。研究成果可为考虑部分排水剪切条件下地基稳定性分析方法的构建提供依据。

In practical situations,soils are frequently subjected to the simultaneous action of consolidation and shearing,namely,sheared under partially drained condition.To simulate this action,the triaxial compression testing method is adopted while keeping the water outlet valve open during shearing at different axial-strain rates.Partially drained shearing tests are carried out on remolded saturated kaolin specimens.The stress-strain behavior under the interactions of volumetric strain and pore-water pressure is analyzed.The test results show that under partially drained condition,the induced pore-water pressure increases and the shear strength decreases with the increase in the rate of axial strain.The critical-state line is,however,independent of the axial strain rate and the drainage condition.