考虑主应力方向影响的正交各向异性土体强度

Strength of Cross anisotropic Soils Considering Influence of Principal Stress Direction

摘要:

利用材料组构与应力主轴的方向关系，对椭圆型角隅函数进行修正并引入到Mohr Coulomb准则，建立了一个适用于正交各向异性土体的三维强度准则.通过所建立的准则，推导了考虑主应力轴方向变化影响的土体峰值应力比与中主应力比关系的计算公式，获得了土体峰值内摩擦角随中主应力比及大主应力偏转角的变化特性.通过与不同沉积面角度条件下的三轴试验及空心圆柱扭剪试验结果对比表明，理论公式预测的内摩擦角与试验结果一致.

关键词:土体强度; 主应力方向; 正交各向异性; 材料组构

Abstract:

According to the relationship between the material fabric and axis of major principal stress, the elliptic shape function was revised by adding a cross anisotropic term, and then a 3D cross anisotropic failure criterion was proposed based on the Mohr Coulomb criterion. The formula for calculating the peak stress ratio under different intermediate principal stress ratio condition was deduced, then the varying characteristics of peak friction angle with the intermediate principal stress ratio and the angle of major principal stress direction relative to material fabric were also obtained. A comparative study of a series of triaxial tests with different sample sedimentation angles and hollow cylinder tests shows that the predicted friction angle agrees well with the experimental results.

Key words:soil strength; principal stress direction; cross anisotropy; material fabric