跨越地铁高层建筑桩筏基础数值模拟研究

Numerical simulation of piled raft foundation of super-tall buildings crossing metro tunnels

基于某跨越地铁高层建筑的设计实践,利用ABAQUS建立剪力墙与桩筏基础和地基共同作用的三维有限元数值模型,研究了跨越地铁隧道的桩筏基础受力和变形性状,并分析了上部结构刚度、逐层施工、地铁隧道跨度、跨越地铁隧道方式等因素对其影响。结果表明,上部为剪力墙结构的高层建筑,考虑上部结构刚度作用可显著减小筏板的差异沉降和弯矩。当上部结构刚度达到一定程度后,其对筏板差异沉降和弯矩的调节能力减弱,表现出上部结构刚度贡献的有限性。随着地铁隧道跨度的增加,筏板最大沉降、差异沉降和弯矩都增大。桩筏基础以筏板对角线与地铁隧道中心线重合的方式跨越地铁隧道对筏板的内力和变形影响最小。桩顶反力数值计算结果与实测数据较为吻合。

Based on the design practice of the tall buildings crossing metro tunnels,a three-dimensional finite element of shear wall-piled raft-soil is proposed to investigate the deformation and internal forces of piled raft foundation.The effects of superstructure rigidity,storey-by-storey construction,span length of metro tunnels and crossing methods are analyzed.The results indicate that considering shear wall rigidity can significantly reduce the differential settlement and the bending moment of raft for high-rise buildings.After superstructure rigidity reaches a certain degree,the differential settlement and the bending moment of the raft per unit load increase slowly.This shows the effects of the superstructure rigidity are limited.With the increase of the span length of metro tunnels,the maximum settlement,the differential settlement and the bending moment of the raft increase slightly.The crossing method of raft diagonal which coincides with the center of metro tunnels has the least influence on the internal forces and the bending moment of the raft.The reaction of piles agrees with the measured data.