岩体斜面上刚性桩基础水平承载力的三维分析与评价

THREE-DIMENSIONAL ANALYSES ON THE LATERAL BEARING CAPACITY OF RIGID PILE FOUNDATION ON ROCK SLOPE

许多重要工程的基础不得不设置在岩体斜面上,但是至今为止此类工程基础的分析理论以及设计方法并没有完全确立。基于一种考虑岩体的低抗拉强度特点的三维弹塑性有限元数值分析,对岩体斜面上设置的刚性桩基础的水平承载力进行了分析与评价,并与现场试验结果进行了比较分析。结果表明,用相对简单的三维有限元分析,可以较好地反映现场试验中所观测到的变形与破坏现象,是一种有效的评价方法。采用同样的方法,对桩到斜面顶端距离以及斜面倾斜角度的变化所带来的对刚性桩基础水平承载力的影响,作了定量的分析与评价,其结果对斜西岩体上刚性桩基础的水平承载力的理论分析以及实际设计具有一定的参考价值。

To develop the rational numerical method for predicting the deformation and failure of the rigid pile foundation on rock slope, a series of nonlinear elasto-plastic FEM analyses were conducted to simulate the field experiment on the bearing capacity and failure deformation of rigid pile foundation on rock slope under the lateral loading. In the analyses, rock was supposed to be a elasto-perfectly Mohr-Coulomb plastic material with or without considering the low-tension strength effect. The results obtained from the FEM analyses were compared with that of the field experiment. It was found that the load-displacement relation and the failure mechanism of the rigid pile foundation obtained from the 3D-FEM analyses, in which the low-tension strength effect for rock was considered, has a good agreement with the field experimental result. In addition, by making use of the above rational numerical method, the effects of distance from pile foundation to the top of slope and slope angle on the lateral bearing capacity were also successfully evaluated.