Research On Key Technique Of Deep Foundation Pit By Top-down Construction Method On Soft Soil Area Of Wenzhou City

With the rapid development of Chinese economy,the scale of the city has been greatly expanded,which shows the surge of urban population and the constant updating of infrastructure.Therefore,the shortage of urban land resources,the large population growth and the relative lag of the infrastructure have become a pair of contradictions on the way of urban development.Development of underground space is becoming more and more acceptable by people and more attention was paid on it.The reverse construction method stands out,and plays an extremely important role in the construction of the city.But there are still some problems in the practice of reverse construction technology,in order to better promote the implementation of the reverse,this paper combined with the specific project,researched and explored the reverse construction process,in order to provide a positive guidance for the promotion of the reverse construction technology in Wenzhou areas.The main contents of this paper are as follows:(1)Briefly described in this paper,we study the background and significance,the development of the research and application status at home and abroad,based on the basic theory of uni-axial,from the Angle of economic and technological uni-axial and practice is analyzed and compared.(2)The enclosure structure,horizontal structure,vertical structure,excavation earthwork and the treatment of various key joints in the reverse method are systematically analyzed,and the control of the settlement difference of the reverse construction method is also studied.(3)Some key technical problems in deep foundation pit uni-axial has carried on the research,mainly includes the external retaining structure technology and construction quality control,reverse conditions of earthwork excavation method,reverse and organizations for the kinds of connections under the condition of the basement structure nodes in the structure and construction,uni-axial generation and control of differential settlement,discussed the three factors of carrying capacity of decision supporting columns,the columns and column pile connection,supporting the upper load of verticality and supporting columns(4)Given the reverse construction method has obvious social and economic benefits,the application of reverse engineering,combined with the construction of Wenzhou business building opportunity,emphatically expounds the main construction technology of reverse construction,such as the construction of bored pile construction,cement mixing pile column pile construction technology,excavation and the dark digging combination method,adopted a series of effective construction technology,and real-time monitoring of the foundation pit,timely control of foundation pit surrounding environment of settlement and horizontal displacement of slope,the slope settlement of key parameters,to ensure the safety of the implementation of the project.