基坑开挖对邻近任意角度建筑物影响的有限元分析

Finite element analysis of response of buildings with arbitrary angle adjacent to excavations

实测结果表明,邻近基坑的建筑物与基坑边互不垂直时,基坑开挖将导致墙体同时发生挠曲变形与扭转变形。三维有限元分析表明,对与基坑边成一定角度的建筑物,当其跨越坑外沉降槽最低点或沉降曲线上凸区域时,建筑物所产生的扭转变形最为显著。随着建筑物与基坑距离的变化和建筑物纵墙与基坑边之间夹角的变化,当建筑物位于天然地面沉降挠曲程度较大的位置时,建筑物的挠曲变形对墙体拉应变起主要作用,墙体最大拉应变发生在建筑物纵墙垂直于基坑边,即纵墙与基坑边相互垂直时是建筑物的最不利位置;而当建筑物位于天然地面挠曲程度较小的位置时,墙体的拉应变源于挠曲变形与扭转变形的共同作用,纵墙墙体的最大拉应变将发生在与基坑边成一定角度的建筑物纵墙上,此时纵墙与基坑边垂直并不是建筑物的最不利位置。

The measured results show that the excavation leads to both deflection deformation and torsion deformation of the building not perpendicular to the retaining wall. When this kind of building is located over the lowest point or the hogging zone of the settlement trough, the torsion deformation of the building is the most obvious according to the 3D-FEA results. With the variation of the distance and the angle between the building and the retaining wall, when the deflection deformation becomes the major cause of the tensile strain, the maximum tensile strain occurs on the longitudinal walls perpendicular to the retaining wall. In this case, the longitudinal wall perpendicular to the retaining wall is in most adversity. When the deflection deformation is slight, the deflection deformation and torsion deformation cause the tensile strain together, and the maximum tensile strain occurs on the longitudinal walls not perpendicular to the retaining wall. In this case, the longitudinal wall perpendicular to the retaining wall is not in most adversity.