Study Of The Effect Of Leakage From Pit Stop Structures On The Surrounding Soil And Building Deformation

With the continuous development of economic construction and the increasing development and use of underground space,the problems facing the development of foundation pits are becoming more and more prominent.The vulnerability to soil and water leakage at the joints of the foundation pit diaphragm wall or at the mud trap of the water stop curtain often restricts the further development of the pit.Leakage in foundation pits is often concealed and hazardous,and there is still a lack of consideration of the impact of diaphragm wall leakage on the deformation of adjacent buildings.In this paper,indoor model tests and numerical simulations are used to investigate the mechanism of seepage and erosion,the rate of soil erosion and the development of soil deformation affected by different factors in the surrounding soil after the leakage of water and sand from the underground diaphragm wall,and to establish a numerical model that considers the effect of water and sand leakage from the foundation pit stop structure on the deformation of the surrounding soil,wall and building.The main research content in this article is as follows:(1)Through self-designed leakage and sand leakage test device,the spatial pattern formed by soil leakage and erosion is studied,the influence of factors such as head,soil type and different sizes of leakage on the pattern of the cavity is analysed,the development process of soil erosion is studied for the soil,the scope of influence of leakage on the surrounding soil is studied,and the deformation characteristics of the soil seepage and erosion process are derived.Among them,the maximum surface settlement value for a seepage seam of 10 mm is approximately four times the maximum surface settlement value for a seepage seam of 5mm.(2)Using the finite element method to establish a numerical model considering the influence of the foundation pit wall leakage conditions on the surrounding strata and enclosure structure,the soil deformation results on the non-leakage side of the wall are compared with the empirical and measured values to verify the numerical model and analyse the influence of the wall leakage point height,soil parameters and wall insertion depth on the deformation of the surrounding soil and enclosure structure under the foundation pit excavation.Among them,the seepage point height has the greatest influence,with a maximum ground settlement value of 37.5 mm.(3)Through numerical simulation,the effects of wall leakage point height,building and pit relative position,building pile length,building and pit distance and soil parameters on the deformation of adjacent buildings are investigated,and the characteristics of soil settlement and building deformation around the pit are investigated under different influencing factors.(4)The installation of row pile reinforcement or diaphragm wall reinforcement on the leakage side of the diaphragm wall has a significant control effect on the vertical displacement of the soil outside the pit,which can reduce the settlement of the ground surface to a greater extent and reduce the impact of leakage on the foundation pit and the adjacent buildings.The maximum ground settlement values were reduced from 18.87 mm to 12.89 mm and 10.75 mm respectively by the pile and diaphragm wall reinforcement solutions,and the diaphragm wall reinforcement was more significant in reducing the foundation pit deformation.