深基坑降水对周围建筑物沉降的影响

应用有限差分程序FLAC3D的流固耦合功能和三维数值模型分析了基坑降水时影响周围地表及建筑物沉降的主要因素,包括地表建筑物的存在与否、建筑物与基坑的相对位置、基础特性(如基础面积、埋深、刚度和基础形式等)以及相邻建筑物的相互作用等.计算结果表明:建筑物的附加应力场及其基础形式对地表沉降预测有影响,不考虑建筑物的基础形式时,对于浅基础建筑物,预测结果偏小,对于桩基础建筑物,预测结果偏大;浅基础建筑物的最大沉降及最大差异沉降与基础的埋深和刚度有关,埋深增加时,最大沉降减小,但最大差异沉降会有所增加,刚度增大时,二者都会变小;相邻建筑物的影响取决于建筑物与基坑的相对位置,在基坑轴线方向的影响要大于平行基坑边缘方向的影响.

Building Settlements Induced by Dewatering in Deep Foundation Pit

The fluid-mechanical coupling function in the finite difference program FLAC3D and 3-dimentional numerical method are used to analyze different factors that affect the surrounding ground and building settlements induced by dewatering during excavation of deep foundation pit.These factors include exsiting buildings or non-buildings on the ground,different positions between buildings and the deep foundation pit,foundation characteristics(such as area,depth,stiffness,form,etc.)and interactions between adjacent buildings.The simulation results show:(a)that the additional stress field and the foundation form have influence over the estimation of ground settlement,in which the ground settlement is underestimated for buildings with shallow foundation but overestimated for buildings with pile foundation as compared without considering existing ground buildings.(b)that the largest settlement and differential settlement of a building with shallow foundation are related to the foundation depth and stiffness,i.e.for increasing foundation depth the largest settlement decreases but the largest differential settlement increases,while for increasing stiffness the both settlements decrease.(c)that the interaction between adjacent buildings depends upon the relative position of these buildings from their foundation pit,generally,the influence of interaction in the axial direction is larger than that in the direction parallel to the edge of foundation pit.