Analysis On Working Behavior And Stability Of Deep Foundation Pit In Soft Ground Considering Impact Of Engineering Piles

At present, all kinds of underground space have been used in the construction in the major cities around the world during the developing period. The multi-storey basement of high-rise buildings, subway and underground stations, underground garage and other underground facilities are related to all kinds of deep foundation pit works. The high-rise building foundation in the soft soil area is often in the form of pile foundation, and the piles are excavated before excavation.The piles that have been set up will have an impact on excavation of pit, the release of soil stress in the pit, and the rebound of bottom of the soil at different levels. Due to the complexity of the deep foundation pit engineering and the regional nature of the geotechnical engineering itself, it is necessary to study the excavation behavior and stability of the foundation pit in foundation pit excavation project.Firstly, based on Plaxis finite element software, a finite element model of 3D foundation pit excavation considering the existence of piles is established by using HSS model. The excavation behavior of the foundation pit considering the existence of the piles is studied, that is, the horizontal displacement of the envelope, the internal force of the envelope, the settlement of soil outside the pit, the distribution law and the spatial effect of soil uplift. The effects of pile diameter,pile rigidity, insertion depth, pile spacing and distribution on the working behavior of foundation pit are discussed.Secondly, the spatial distribution law of pile displacement, axial force, moment and side friction of piles in the pit excavation process is studied. The Influence of the depth of excavation and supporting piles, and length of piles on working behavior of piles are discussed.At last, the strength reduction finite element method is used to analyze the influence of pile diameter, pile length, pile spacing and distribution form on the stability of foundation pit.