Study On Checking Optimization Of Supporting Structure For Deep Foundation Pit Of Pumping Station

With the continuous development of infrastructure construction,the number of foundation pit enclosure projects is increasing,and the scale of construction is also growing.The engineering problems encountered and aspects involved are also becoming increasingly widespread.In the construction of foundation pits,the supporting structure plays an important role in the safety and stability of foundation pits,and the optimization design of the supporting structures has gradually become one of the major research issues at present.This article relies on the "Study on Optimization of Supporting Structure for Deep Foundation Pit of Pumping Station" project,using numerical simulation and centrifugal model tests to optimize the supporting structure of foundation pits and determine the optimal supporting structure scheme.The main research contents and results include:(1)Considering the difference between the actual foundation pit excavation depth and the supporting form,it is divided into left and right parts for computational studies.The finite element software ABAQUS is used to simulate the excavation process of left foundation pit under the original support structure.The deformation of retaining structure,the change of bending moment and the surrounding ground settlement were studied,and the study provides a reference for follow-up support optimization.The results show that with the increase of excavation depth,the horizontal displacement,wall bending moment and ground surface settlement of the retaining wall also gradually increase,and the maximum horizontal displacement and bending moment of retaining wall gradually move downward with the increase of excavation depth.(2)Based on the theoretical analysis of foundation pit deformation of original support structure,the finite element model of left side foundation pit is established.Based on the finite element simulation results,the influence of different support parameters on the deformation of foundation pit is analyzed,and orthogonal test is used to determine the optimal support structure for left sided foundation pit.The results show that the greatest impact on foundation pit deformation is the pile diameter,followed by the length of pile,the concrete strength grades of pile and the support section size.And the concrete strength grade of supporting has almost no effect on it.(3)Based on the optimization results of left-side foundation pit supporting structure,the new supporting structure of right-side foundation pit is initially determined and a corresponding finite element model is established.The deformation of foundation pit under the two supporting structures is analyzed and compared to verify the rationality of new protection structure.The results show that the deformation of the right foundation pit under the new supporting structure has increased,but the foundation pit is still in a safe and stable state.(4)An indoor centrifugal model test was conducted to simulate the excavation process of foundation pit under the original support structure and the new supporting structure.The deformation of foundation pit under the two supporting structures was compared and analyzed to verify the feasibility of test method and the rationality of new support structure,and provides useful lessons for similar projects in the future.The results show that the horizontal displacement of piles,the bending moment of piles and the surrounding ground surface settlement of the foundation pit under the new support structure are increased correspondingly to the original support structure,but they are all within a reasonable control range.It is proved that the foundation pit under new supporting structure is safe and stable.