初始主应力方向对饱和粉土不排水剪切特性的影响

Effect of orientation of initial principal stress on undrained shear behavior of saturated silt

利用"土工静力–动力液压–三轴扭转多功能剪切仪",针对山东东营原状饱和粉土和采用3种初始成样含水率夯击法制备的重塑饱和粉土,在初始平均主应力为100 kPa,初始中主应力系数为0.5,初始偏应力比为0.433,初始主应力方向角分别为0°,30°,45°,60°,90°的非均等固结条件下,保持平均主应力和中主应力系数恒定进行了应力控制式不排水静力扭剪实验。着重探讨了初始主应力方向和初始成样含水率对粉土应力–应变关系、孔隙水压力变化与有效应力路径等的影响。实验结果表明:初始主应力方向对原状粉土和重塑粉土的变形与强度特性的影响程度有所不同;初始成样含水率对饱和重塑粉土的变形及强度特性具有显著影响。

By using the soil static and dynamic universal tri-axial and torsional shear apparatus, the stress-controlled undrained static torsional tests are performed on Dongying intact saturated silt of Shandong province and remolding saturated silt prepared by tamping method controlling three kinds of the initial sampling water contents. The conditions of the initial anisotropic consolidation are the initial mean principal stress of 100 kPa, the initial intermediate principal stress coefficient of 0.5, the initial deviator stress ratio 0.433 and the initial orientation angle of the principal stress respectively at 0°, 30°, 45°, 60°, 90°. During the undrained monotonic sheafing process, the mean principal stress and the intermediate principal stress coefficient are fixed. The effects of orientation of the initial principal stress and initial sampling water content on the stress-strain relations, the pore pressure development as well as the effective stress paths are studied. The test results show that the effect degree of the initial principal stress orientation on deformation and strength behavior of intact silt is different from that of the remolding silt. The initial sampling water content has considerable influence on the test results of the saturated remolding silt.