Research On Utilization Of Existing Retaining Wall Under Excavation In Front Of Wall

In recent years,with the rapid development of urban construction,in order to make use of the existing retaining wall,more and more slope projects adjacent to the existing retaining wall construction have appeared.In this type of project,the slope is divided into the existing gravity retaining wall slope,the existing pile-sheet retaining wall slope,and the existing anchor retaining wall slope according to the common existing retaining wall form.Some scholars have conducted research on such slopes,but the research is not deep enough and extensive.Based on this,this paper relies on the Chongqing Shapingba Shuangbei Sunshine City Slope Foundation Pit Project,taking three of the existing retaining walls（gravity retaining wall,pile-shell retaining wall and anchor retaining wall）as the research object,using theory analyze and combine numerical analysis methods to study them separately,specifically studying the changes of the force and stability of the existing retaining wall under the topdown construction method in front of the wall.Among them,the numerical analysis method is mainly combined with FLAC^3D numerical software to establish analysis models of the typical cross-section slopes of the existing retaining walls,and to simulate the construction process in order to analyze and study the existing retaining wall.The main work done in this article is as follows:（1）Collect engineering and survey data,analyze the three existing retaining walls in the project,select the three typical cross sections of the existing retaining walls,and combine the engineering geology and construction conditions to analyze the existing retaining walls facing the project Some problems.（2）For the existing gravity retaining wall,analyze the specific problems faced by the existing gravity retaining wall;then theoretically analyze the influence of the reverse construction method and the pre-reinforced structure on the force and stability of the existing gravity retaining wall;Using numerical analysis method and FLAC^3Dnumerical software,a slope model is established to simulate the topdown construction process of the retaining wall in front of the wall,mainly to analyze the influence of foundation stress changes and pre-reinforced anchors on the existing gravity retaining wall.（3）For the existing pile-shell retaining wall,first analyze the main problems faced by the existing pile-shell retaining wall in combination with geology and construction conditions,and then use the theoretical method to analyze the excavation in front of the wall and the influence of new retaining wall structure to the existing pile-shell retaining wall;Finally,a numerical analysis method,combined with FLAC^3D finite difference software,is used to establish an analysis model for the selected typical section,and to simulate the construction process,mainly to study the displacement of the foundation rock mass of the existing pile embedded section.（4）For the existing anchor retaining wall,relying on the project to specifically analyze the main problems faced by the existing anchor retaining wall,and also theoretically analyze the impact of reverse construction on its stress and stability,and finally use the numerical analysis method,Combined with FLAC^3D finite difference software,for the two different situations of the adjacent excavation in front of the existing anchor retaining wall in the project,the selected degraded platform reserved for the existing anchor retaining wall and no pre-existing The typical sections of the excavation slope in front of the two walls of the degraded platform left for excavation were established numerical models and simulated in conjunction with the construction process,mainly to study the stress changes of existing anchors.