管状地下结构对软土场地浅埋筏式基础震陷影响规律模拟研究

Numerical investigation on the influence of underground tubular structure on seismic subsidence of shallow raft foundation in soft soil site

为探究软土场地内管状地下结构对浅埋筏形基础震陷的影响规律,基于FLAC3D有限差分分析平台及振动软化模型建立了筏式浅基础软土震陷分析方法,通过对比1976年唐山地震中天津塘沽新港地区典型房屋基础的软土震陷震害模拟值结果与实测值验证了该方法的合理性。建模分析不同埋藏条件和截面尺寸的方形(为例)截面管状地下结构对筏式浅基础结构震陷影响规律。研究指出,管状地下结构对自重较轻上部结构的基础震陷的影响更加显著,影响厂房类结构的设计与建造;震陷随着管状地下结构截面相对尺寸的增大而减小,超过地基宽度后会趋于稳定;震陷随着管状地下结构埋藏深度的增加而增加,最终会趋于没有地下结构的结果;震陷随着管状地下结构与房屋埋设距离的增加先增大后减小;从震陷控制角度,管状地下结构选线需要控制与既有建筑的距离。

To study the influence of the underground tubular structure on the seismic subsidence of shallow raft foundations in the soft soil site,a method for analyzing the seismic subsidence of the shallow raft foundation in soft soil was established based on the FLAC3 D finite difference analysis platform and vibration softening model.By comparing the simulated and measured values of seismic subsidence and damage of typical building foundations in soft soil of Tanggu Port in Tianjin during 1976 Tangshan earthquake,the rationality of the proposed method was verified.Numerical simulation was carried out for analyzing the influence of different burial conditions and cross-sectional dimensions of square-sectional(for example) underground tubular structures on seismic subsidence of shallow raft foundation.Results show that the underground tubular structure has a more significant impact on the seismic subsidence of the superstructure with a lighter self-weight,affecting the design and construction of workshop structure.The seismic subsidence decreases with the increase of the relative size of the underground tubular structure,and tends to be steady after it exceeds the width of the foundation.Seismic subsidence increases with the increase of the burial depth of the underground tubular structure,and eventually tends to be the result without underground tubular structures.The seismic subsidence initially increases with the increase of the burial distance between the underground tubular structure and building,and decreases afterwards.In terms of seismic subsidence control,the distance from the underground tubular structure to the existing building needs to be controlled.