横观各向同性土体挡土墙被动土压力研究

大多天然土体具有横观各向同性的特点，在同一个模型中，采用分块处理的方法来讨论横观各向同性土的被动土压力变化；基于最小二乘法原理和组构张量理论，研究位移一次和分步多次施加两种方法，计算土体大主应力方向与沉积面法线方向之间的夹角变化，得到模型分块后各分块新的土体强度参数c_i和φ_i，进而分析各向异性下的被动土压力变化。研究表明：考虑土体横观各向同性后，达到极限平衡时土体经多次位移施加得到的被动土压力比一次位移施加要小，且接近库伦土压力理论解；土体沉积面倾斜对被动土压力的影响要比沉积面水平时引起的影响更为显著；4种屈服准则下得到的被动土压力的差异大小与理论分析相符合。

Study on Passive Earth Pressure of Retaining Wall in Transversely Isotropic Soil

Most natural soils have the characteristics of transverse isotropy. Using the method of block processing in the same model to discuss the change of passive earth pressure of transverse isotropic soils, based on the principle of least squares and the theory of fabric tensor, the two methods of one-step and multi-step displacement applications are studied to calculate the angle change between the direction of the major principal stress of the soil and the normal direction of the sedimentary surface. New soil strength parameters c_i and φ_i in each block are obtained, and then the change of passive earth pressure under soil anisotropy is analyzed. When reaching the passive limit equilibrium state in the transverse isotropy soil, the research shows that the passive earth pressure obtained by applying multi-step displacement method, which is close to the theoretical solution of Coulomb's passive soil pressure, is smaller than that of applying one-step displacement method. The change of earth pressure is more significant when the sedimentary surface being oblique than that of the sedimentary surface being horizontal. The differences in passive earth pressures obtained under the four type yield criteria are consistent with theoretical analyses.