Research On The Application Of Top-down Method For Foundation Pit Support Of De Molition And Reconstruction Of Underground Building Adjacent To Metro Line In Urban Core Area

With the continuous improvement of China's social science and technology and economic level,people's demand for the function and space of buildings is growing day by day.The demand for renovation and renovation of existing buildings in urban core area has become a new topic presented to engineers and technicians.Limited by the traffic,production and living needs in the limited space of the city,there are a large number of buildings and structures around the buildings that want to be renovated,such as subway station buildings and lines,important pipelines and pipelines,foundation of other buildings or other tunnel tube well equipment and facilities.The existence of these buildings and structures,on the one hand,forms a certain degree of restriction on the existing buildings to be renovated,on the other hand,the demolition and reconstruction process of existing buildings may also have adverse effects on these buildings.In this context,how to reasonably use scientific and effective means to design the foundation pit support of urban core area underground building structure demolition and reconstruction project has become the top priority of this kind of project.This paper first introduces the current situation,related research content and some research methods of the top-down method of foundation pit support engineering at home and abroad,expounds the general situation of the project to be demolished and reconstructed and the relevant basic information,briefly describes the common comparison method of the design and construction scheme of the foundation pit support engineering,and summarizes the overall idea of the engineering foundation pit support scheme iterative improvement Then,according to the actual situation of the site,the design of the selected support scheme is carried out.The simulation analysis of the foundation pit support design and construction scheme is carried out by using the software "Midas gen","ANSYS" and "Lizheng toolbox".Then,according to the actual needs in the construction process,the design and calculation of the temporary jacking support system of steel frame is carried out,which solves the engineering construction Problems encountered in the process.In this paper,the calculation results of the computer simulation analysis are compared with the field monitoring data in the construction process,and the rationality of the design and construction scheme of the foundation pit engineering is finally verified in the reverse direction,which provides some reference experience for the design of the subsequent similar urban core area underground building demolition and reconstruction project.