Study On The Deformation Law Of Deep Foundation Pit And Its Influence On The Deformation Of Adjacent Bridge Pile

Foundation pit engineering is a common but very complex foundation engineering,and its dewatering excavation will cause engineering problems such as deformation of supporting structure,settlement of surrounding surface and deformation of pile foundation of adjacent buildings.In recent years,the excavation of foundation pit caused damage to adjacent buildings is common,this paper relies on the project for the east extension of Guangqu Road,Tongzhou District,Beijing ZK18+400-ZK18+500 In the first stage of the foundation pit project of the north canal section under the road project,the open-digging method of water is used for slotted construction.Because the average distance between the north side of the construction section and the bridge pile is 20.1 meters.In order to explore the deformation law of dewatering excavation and its influence on the deformation of adjacent bridge pile,by monitoring the dewatering excavation process and combining the MIDAS GTS numerical simulation results under the same working conditions,it is found that the numerical simulation results are basically consistent with the actual monitoring results,The variation rules of soil pressure,internal support axial force,deformation of ground connecting wall,settlement of surrounding surface and deformation of adjacent bridge piles are obtained.On this basis,through the control variable method,using numerical simulation,the change of single parameter is controlled,and the law of different factors affecting the deformation of bridge pile is analyzed.It is found that:(1)the settlement and horizontal deformation of the bridge pile are positively correlated with the rate of dewatering.The faster the precipitation rate,the greater the settlement and horizontal deformation of the bridge pile,and the influence of precipitation on the bridge pile with high water content is greater than that with low water content.(2)The horizontal displacement and vertical settlement of the pier have a negative correlation with the distance from the excavation center,and the farther away from the excavation center,the smaller the horizontal displacement and vertical settlement of the pier,whereas the greater the horizontal deformation and settlement.(3)The maximum horizontal deformation depth of the bridge pile becomes shallow after applying the isolation pile between the ground connecting wall and the bridge pile.(4)The stiffness of the ground-connected wall will also affect the deformation of the bridge pile,and the deformation value of the bridge pile is negatively correlated with the stiffness of the ground-connected wall.According to the above conclusions,the control measures to reduce the deformation of adjacent bridge piles are put forward,and the comparison and analysis of monitoring data and numerical simulation results verify the correctness of the numerical model established in this paper.The relevant conclusions obtained in this paper can be used as a reference for the second phase project or similar engineering cases.