Numerical Analysis Of Mechanical Response In Top-down Construction Method Of Retaining-enclosure Single Wall In Deep Foundation Pit

With the development of our economy and the progress of urbanization,the construction of super high-rise buildings and underground works is increasing,and the deep foundation pit engineering is also increasing.The lack of land resources forces us to make more rational use of underground space.Had to put a higher demand for building foundation pit engineering.Dual-purpose diaphragm wall is widely used in controlling the deformation,shortening the duration and sustainable development,and thus being influenced by the engineers.Based on the example of dual-purpose diaphragm underground continuous wall combined with a deep foundation pit with internal support and support structure,this paper adopts the method of elastic resistance method and numerical simulation to carry out research.The finite element model of the open cut method construction process is established by ABAQUS large-scale finite element software.The two-dimensional numerical analysis of soil,envelope and surrounding environment is carried out.The paper mainly carries out the following aspects of the work:(1)In this paper,the excavation process is calculated and calculated by using the incremental method in the deep foundation pit software.The internal force and deformation of the underground continuous wall during the excavation are obtained,and the settlement of the soil around the foundation pit is predicted.(2)The horizontal displacement of the underground continuous wall and the soil,the deformation of the bottom of the pit and the settlement of the pit outside the pit are systematically analyzed.And compared with the actual monitoring results,verify the accuracy of the model and parameters.(3)ABAQUS finite element software was used to analyze the main parameters,the influence factors of the thickness of the underground continuous wall,the internal support stiffness,the parameters of the soil(internal friction angle,cohesion)and so on were studied.Influence of influencing factors on the lateral displacement of "two-wall".The analysis shows that there is a certain control effect on the deformation of the wall by increasing the thickness of the underground continuous wall,but it has little effect on the wall deformation when it increases to a certain range.The horizontal displacement of the underground continuous wall decreases with the increase of the internal support stiffness,and the decrease degree decreases gradually.When the stiffness increases more than a certain range,it has little effect on the deformation of the wall.Through the change of the cohesion and the internal friction angle of the soil during the modeling process,it is found that the deformation of the underground continuous wall will change greatly,and the internal friction angle has a greater influence on the wall deformation.These practical conclusions can provide a reference for the similar design of foundation pit support structure.