低围压水平下砂的排水行为(英文)

Drained Behavior of Sand Under Low Confining Pressure

采用干样沉降法制备样品 ,选用静三轴仪对松砂和密砂样在 10 k Pa至 10 0 k Pa的低围压下的排水行为进行了实验研究 ,并对实验结果作了橡皮膜校正 ,在围压为 10 k Pa的密砂实验中 ,轴向应力的校正值可达到 12 %。实验研究表明低围压下松砂的剪胀性非常明显 ,且存在剪应力极值 ;围压越低 ,松砂和密砂的剪应力极值越小 ,达到最大剪应力所对应的剪应变越小。同时还表明低围压范围内相对密度不同 ,砂的应力应变特性不同 ;此外 ,低围压下砂的内摩擦角高于高围压下的值 。

The drained behavior of Hokksund sand under low confining pressure was studied through static triaxial test, and the samples were prepared through the dry sedimentation method. The test results were corrected through the membrane effect which is often neglected under high confining pressure, the correction to axial stress for dense sample under a cell pressure of 10 kPa is equal to 12%. It is demonstrated that the dilatancy behavior of loose sand under low cell pressure is obvious and there exists a maximum shear stress for loose sand; the lower the cell pressure, the smaller the maximum shear stress and the smaller the corresponding axial shear strain for both loose and dense sand. At the same time, it is found that the stress strain behaviors of sand with different relative densities are different; in addition, the lower the confining cell pressure, the bigger the internal frictional angle of sand, so attention should be paid to the selection of parameters for sand under low cell pressure in practical engineering.