Study On The Influence Of Deep Foundation Pit Construction On Adjacent High-rise Buildings

This article focuses on the influence of deep excavation construction on nearby buildings and analyzes and summarizes the theoretical research results of predecessors.Firstly,based on the principles of Darcy’s law,the Dupuit formula,and the hydraulic jump equation,the improved seepage funnel curve equation was derived by incorporating vertical seepage and hydraulic jump value into the mass conservation principle to overcome the theoretical limitations of the previous research.Secondly,experiments with internal models were carried out to simulate the process of forming excavation pipes under the conditions of clay and sandy soil.The deformation mechanism at different stages of dewatering and different positions of the soil layer during excavation was analyzed to obtain the relationship between the amount of soil settlement and the depth of precipitation and different locations of soil layers,etc.Combining the characteristics of the surrounding building environment around Kangwang Road and Changshou Road Intersection in Liwan District,Guangzhou,a computer-aided model of the Hualinsi underground stop was made using the Midas GTS NX application.which was then used to simulate the excavation and deep substructure pit dewatering procedures.The simulation data obtained were compared and analyzed with the actual engineering settlement data,and the effects of deep foundation pit construction conditions on adjacent high-rise buildings were investigated in terms of different excavation depths,water leap values,and rebound of the water table after construction.The main conclusions of this article are as follows:(1)The improved precipitation funnel curve equation formed by deep pit precipitation is an improvement based on Darcy’s law,Dupuit’s formula,and other conditions.The Dupuit well flow model is improved by considering the effects of the water jump phenomenon and vertical infiltration recharge(expressed as a negative value by evaporation),and the water level equation associated with the new model is established,and the new model equation fits well when compared with Chen Chongxi’s groundwater level equation with infiltration recharge.(2)The settlement pattern of soil surrounding the foundation pit was determined to be funnel-shaped through indoor model experiments conducted on clay and sandy soil.As the distance from the foundation pit grows,the settlement initially rises and then falls.Furthermore,the settlement of soil was found to be closely related to the depth of excavation dewatering.The maximum settlement of the soil is roughly proportional to the depth of dewatering.(3)A finite element model was established for a deep excavation at a certain subway station.The data on surface settlement and groundwater level around the excavation were extracted under the construction conditions of the deep excavation.A comparison and analysis were made between the data on surface settlement around the excavation and the monitoring data,and the groundwater level data was verified with the improved rainfall infiltration model in Chapter 2.This proves the rationality of the model.(4)A model made with finite elements of a high-rise framework was established,and highrise structural columns along the direction of the excavation pit and the vertical direction of the excavation pit were selected to study the effects of different excavation depths,different hydraulic jump values,and groundwater rebound conditions on the structural column headings’ horizontal displacement.The findings revealed that the horizontal displacement of the structural columns in the vertical position of the digging pit rose gradually from the pit’s corner to its center.The downward movement of the foundation columns along the path of the excavation pit while growing as the distance from the excavation pit shrunk.Under different hydraulic jump values,the maximum horizontal displacement of the structural columns first decreased and then increased with the increase of the hydraulic jump value.After excavation dewatering,the groundwater rebound would increase the horizontal displacement of the high-rise building’s structural columns,but its impact was not significant.(5)The basement floor at distances of 0m,3m,and 6m from the ground surface was selected to study the three-dimensional deformation under different excavation depths and hydraulic jump values.According to the findings,the side closest to the foundation hole had more deformation.The deformation of the cellar floor grew as the depth of the excavation decreased.When the excavation depth was not large,the deformation of the basement floor decreased as the depth increased.The deformation of the basement floor decreased with the increase in hydraulic jump value.(6)During the excavation of the basement floor of a high-rise building,the overall deformation of the basement floor protrudes upwards.As the excavation depth increases,the deformation becomes more pronounced,with a deformation pattern of protrusion,depression,and then protrusion along the vertical direction of the foundation pit.Under different water head conditions,the overall deformation of the basement floor along the vertical direction of the foundation pit is a protrusion,and the deformation pattern along the vertical direction of the foundation pit is protrusion,depression,and then protrusion.By comparison,it is found that the deformation is greater under the water head condition of 3 meters.