为考虑细颗粒填土强度各向异性对土压力的影响,通过直剪试验测定了压实粉质填土多个剪切面上的抗剪强度,证明抗剪强度参数和剪切面倾角之间的关系可用椭圆形函数表示。在朗肯土压力基本假定基础上,假定墙后为横观各向同性填土且压实面水平,通过对处于主动极限状态下的滑动土楔进行受力分析,得到了滑裂面倾角和主动土压力合力的表达式。对墙后填土的极限应力状态的分析表明,作用于墙背上的主动土压力为线性分布。参数分析表明,不论考虑黏聚力各向异性还是考虑内摩擦角各向异性,都会得到比各向同性填土更大的主动土压力值。和各向同性填土相比,黏聚力各向异性会使滑裂面更陡。同时,考虑内摩擦角各向异性时,在内摩擦角较小的填土中会得到更陡的滑裂面,而在内摩擦角较大的填土中,则会得到较缓的滑裂面。

In order to consider the effect of strength anisotropy on earth pressure, the shear strengths on different shear planes of compacted silty fill are measured by direct shear tests. It is proved that the relationship between shear strength parameters and the dip angle of the shear plane can be expressed by the elliptic function. On the basis of Rankine's assumption of earth pressure, assuming that the transverse isotropic fill behind the wall has a horizontal compaction surface, the expressions of the dip angle of the slip surface and the resultant force of active earth pressure are obtained by analyzing the force balance of sliding wedge in the active limit state. The analysis of the ultimate stress state of the fill behind the wall shows that the active earth pressure acting on the back of the wall is linear. Parameter analysis shows that considering the anisotropy of cohesion and the anisotropy of internal friction angle, the active earth pressure value is greater than that of isotropic fill. Compared with isotropic fill, the anisotropy of cohesion makes the slip surface steeper. In addition, considering the anisotropy of the internal friction angle, the steeper sliding surface will be obtained in the fill with a smaller internal friction angle, while the slower sliding surface will be obtained in the fill with a larger internal friction angle.