考虑初始不均匀沉降的建筑物受基坑开挖影响的有限元分析

Finite element analysis of responses of building adjacent to excavation considering initial differential settlement

在考虑土体的小应变现象及建筑物初始变形的基础上,研究了邻近建筑物与基坑相对距离的变化及自身刚度变化对建筑物不均匀沉降的影响。对于纵墙垂直于基坑边,且跨越坑外沉降槽最低点时,墙体产生的下凹挠曲变形与建筑物的初始变形趋势相同,初始变形将在一定程度上增大墙体的拉应变,尤其是对于刚度较小的建筑物,初始变形对墙体拉应变的影响将更为显著,此时考虑建筑物的初始变形是很有必要的;而当纵墙垂直于基坑边,且处于坑外土体上凸区域时,初始挠曲与基坑开挖产生的挠曲变形趋势相反,此时不考虑建筑物的初始变形则是偏于保守的。当建筑物部分处于下凹区、部分处于上凸区时,对于建筑物的下凹区部分也应考虑其初始变形的影响。

Considering the initial differential settlement of buildings as well as small strain characteristic of soil, the impact of the distance between the building and the excavation and the stiffness of the building on the differential settlement are analyzed. It is necessary to consider the initial differential settlement of the building. When the longitudinal walls of the building are perpendicular to the retaining wall and are located over the lowest point of the settlement trough, sagging deformation occurs and its trend is the same as the initial settlement. So the initial deflection increases the tensile strain. In this case, taking account of initial deflection is necessary. Especially for the building with low stiffness, the influence of the initial settlement on the tensile strain of the building is more obvious. When the longitudinal wall of building is perpendicular to the retaining wall and located over the hogging zone of the settlement trough, taking no account of initial deflection is conservative since the deflection trend is opposite to the initial settlement. When the longitudinal walls are located over the sagging and hogging zone, the initial deflection should be considered in the sagging zone.