非饱和重塑黄土的三轴试验研究

Study of the tri-axial experiment for the remodeled unsaturated loess

采用压力板仪和非饱和土三轴仪,针对兰州和平镇的非饱和重塑黄土进行了压力板试验和一系列的控制吸力的三轴试验,研究结果表明:相同含水率条件下,干密度小的土样吸力较大;相同吸力条件下,干密度小的土样含水率较高;低吸力范围内含水率变化较大;不同吸力和不同干密度的试样均呈应变软化;干密度对凝聚力和有效摩擦角两个参数有不同程度的影响,而吸力仅对凝聚力影响较大,对有效内摩擦角的影响可忽略。根据试验结果确定了该土的强度表达式及其参数,为工程应用提供了依据。

The press-panel and the tri-axial device for testing the behavior of unsaturated soil is used in the shear tests with controlled suction,in which unsaturated soil collected from the Heping town in Lan Zhou city are tested.The test results show that suctions are higher with the lower dry densities,and on the other hand,the water contents are higher with the lower dry densities.Different suctions and different dry densities have the same strain softening phenomenon.The cohesion and effective inner friction angles are influenced by the dry densities.The influence of suctions on the cohesion is apparent,whereas this effect is negligible as for the effective inner friction angles.The strength expression and values of relevant parameters of the soil are proposed according to the test results,which could be used as a reference in field applications.