Study On The Influence Of Manual Digging Construction Of Concrete Retaining Wall On Existing Structure Based On FLAC^3D

With the acceleration of urban construction in China,urban underground space development and technology research have received more and more attention.The subway is one of the important ways of underground space utilization.Pile foundation breaking construction is often required during subway construction.When the artificial retaining wall of concrete retaining wall breaks the original bridge pile foundation,it has important engineering application value to monitor and study the settlement deformation law of the original bridge structure foundation.Based on the Xi'an Metro Line 1 under the Xisanhuan Zaoqiao Pile Foundation Underpinning Project,the theoretical analysis,on-site monitoring and numerical simulation are combined to study the settlement deformation law of the original bridge structure foundation.This thesis first introduces the deformation mechanism of artificial excavation of foundation pit with concrete retaining wall,and then introduces the monitoring scheme of artificial excavation of abandoned Bridge Piles for the concrete retaining wall of Zaohe Bridge in the West Third Ring,and analyses the monitoring results of ground settlement around foundation pit and settlement deformation of pile foundation of existing bridge structure caused by manual excavation.Then using FLAC^3D to simulate the construction process of manual excavation of concrete retaining wall and removal of abandoned bridge piles.Comparing and analyzing the calculation structure and the measured data under different working conditions.The main contents and conclusions of this paper are as follows:?1?The deformation mechanism of artificial excavation foundation pit with concrete retaining wall is analyzed,and the finite element software FLAC^3D used in this paper is introduced.?2?The monitoring schemes of ground settlement around the foundation pit and settlement and deformation of pile foundation of existing bridge structures during manual excavation with concrete retaining wall are described in detail.?3?The field monitoring data are analyzed and studied.It is found that with the increase of excavation depth of artificial foundation pit with concrete retaining wall,settlement deformation of bridge pile foundation increases gradually,and surface settlement deformation around foundation pit changes from triangle distribution to groove distribution.?4?FLAC^3D is used to simulate the excavation process of deep artificial foundation pit with concrete retaining wall.There are some differences between the numerical simulation of settlement of existing structures and that of measured structures,but the overall trend is the same.The ratio of the measured results to the numerical analysis structure is analyzed by means of mathematical statistics.The analysis results show that the construction stage and different existing structures have no significant influence on the ratio prediction of the final numerical analysis structure to the measured structure.The revised FLAC^3D simulation can be used to predict the ground deformation around the foundation pit and the settlement of the foundation of the structure.It can be used as a reference means to predict the settlement deformation before the construction of the project.