考虑坑外渗流自由面变化的基坑工程性状分析

Analysis of the Behaviors of Foundation Pit with Excavation Considering Variation of Seepage Free Surface

摘要:

通过对基坑工程进行考虑孔压消散与变形耦合效应的有限元分析,得到了坑外渗流自由面随时间的变化规律,并研究了坑外渗流自由面变化对基坑内外超静孔压、土水势以及基坑变形的影响.研究表明,考虑坑外渗流自由面变化时,坑内外的超静孔压和土水势都减小;坑外渗流自由面的变化使得坑外水压力减小,有效应力增加,并引起坑内外的水头差降低,因而使得支护墙的水平位移和坑底的隆起变形减小,坑后的地表沉降增加.

Abstract:

Variation of seepage free surface with time is analyzed by finite element method that can perform the coupled analysis of soil mass deformation and pore water pressure dissipation,and the influence of variation of seepage free surface on excess pore water pressure,soil water potential and foundation pit deformations are also further investigated.It is indicated that excess pore water pressure and soil water potential will decrease when variation of seepage free surface outside the foundation pit is considered.Variation of seepage free surface causes the decrease of water pressure and the increase of effective stress outside the foundation pit,and also causes the decrease of the water head difference between the inside and outside of the foundation pit,and thus further results in the decrease of retaining structure horizontal displacement and pit base heave and the increase of ground surface settlement.