高填方路堤下CFG桩复合地基渐进破坏分析

Analysis on Progressive Failure of CFG Pile Composite Foundation Under High⁃fill Embankment

对地基反力系数法中地基土体水平位移进行修正,将桩体断裂位置以上土的位移按系数分配给相邻桩体,然后将桩土位移差值代入微分方程求解桩身位移和弯矩,得出了桩体断裂后相邻桩体的变形与受力情况的计算公式。利用软件ABAQUS中的XFEM模块模拟了实际高填方路堤工程中桩体的弯矩、断裂位置及顺序,验证计算的正确性和适用性。结果表明:理论公式对路堤边缘位置桩体的弯曲情况描述的较好,桩身弯矩变化规律、桩身弯矩最大值、最大值发生位置与数值计算模型拟合相近。理论计算公式通过分配桩体断裂位置以上土的位移给相邻桩体并求解微分方程,能够有效描述桩体断裂后邻桩的弯矩增量,判断桩体的安全性。

The horizontal displacement of the foundation soil in the foundation reaction coefficient method was modified,and the displacement of the soil above the pile fracture position was distributed to the adjacent piles according to the coefficient.Then the displacement difference between the pile and the soil was substituted into the differential equation to solve the pile displacement and bending moment,and the calculation formula of the deformation and stress of the adjacent piles after the pile fracture was obtained.The XFEM module of ABAQUS was used to simulate the bending moment,fracture position and sequence of piles in the actual high-fill embankment project to verify the correctness and applicability of the calculation.The results show that the theoretical formula can describe the bending of pile at the edge of embankment well.The variation law of pile bending moment,the maximum value of pile bending moment and the location of the maximum value are similar to the numerical calculation model.The theoretical calculation formula can effectively describe the bending moment increment of adjacent piles after pile fracture and judge the safety of piles by distributing the displacement of soil above the pile fracture position to adjacent piles and solving the differential equation.