Numerical Simulation Of Deep Foundation Pit Construction By Reverse Engineering Method And Its Influence On Deformation Of Adjacent Subway Stations

With the development of city, foundation construction has changed from shallow foundation to deep foundation.The deep foundation construction environment in the center of cities is poor, and the excavating sequences and measures are not reasonable, which leads to the surrounding ground settle, structure failure of adjacent buildings, the rupture of underground pipelines, and some other engineering accidents.Modern foundation construction engineer involves many fields and subjects, and the research of it is very complex.Many scholars from home and abroad have done a lot of fruitful work on deep foundation construction. However, the complex scene of deep foundation construction involves many factors, so the research has unique characteristics, thus accurate numerical model and the simulation of construction technology are the powerful guarantee for deep foundation construction.After concluding and analyzing several related theories on deep foundation construction, the research combines one deep foundation construction in KunMing, and adopts three dimension finite element analysis software of MIDAS GTS, thus builds the accurate three dimension finite element model via taking key factors into consideration. The conclusions after the modeling research of the whole procedure of the deep foundation construction are:(1)With the growth of the depth of excavation, the displacement of continuous wall also increases. When excavating to the design depth, the displacement of continuous wall reaches to maximum, and the max absolute value is 11.77mm.(2)With the growth of the depth of excavation, the internal force of continuous wall changes. The maximum of the bending moment Mxxof the continuous wall is-153.3 kN·m/m, and the maximum of MYY is-189.2 kN·m/m. The bearing of continuous wall in the process of deep foundation construction is small.(3)With the growth of the depth of excavation, the displacement of adjacent buildings also increased. When excavating to the design depth, the displacement of continuous wall reaches to maximum. The maximum displacement of subway station is 1.27mm. The maximum displacement of entryway is 8.7mm.The maximum displacement of shield tunnel is 0.97mm.(4)With the growth of the depth of excavation, the internal force of adjacent buildings also increases. The maximum value of the bending moment in subway station is 537.0kN ·m/m.The maximum value of the bending moment in entryway is 223.9 kN ·m/m.The maximum value of the bending moment in shield tunnel 198.4kN ·m/m.(5)According to the definition of relevant specifications, the continuous wall and adjacent buildings are all safe in the process of excavation.(6)Through simulation analysis and comparison of the influence of adjacent buildings in different excavation methods and excavation under different distanc-e from the foundation,summarized the influence of excavation on adjacent buil-dings,reinforcement measures provide areference whether to take on adjacent b-uildings.The research of this paper provides reference and guidance for the eco-nomic rationality of the design and construction of foundation pit engineering.