Study On Deviation Rectification Technology Of Existing Building Excavation Based On Pile Underpinning

Due to weak soil foundation,poor soil,the use of poor management and other reasons,resulting in building incline accidents occur.What kind of treatment applied to strengthening and rectification of inclined buildings can ensure the safety,resource conservation,environmental protection,which is of great significance.Conventional reinforcement rectification technology is usually separated from the rectification and reinforcement,resulting in complex construction process,longer construction period.In this paper,based on the existing methods of reinforcement and rectification technology,this paper puts forward the reinforcement technology of pit excavation based on pile underpinning,which combines the reinforcement of foundation and the rectification of the building.The method not only shorten the construction period,but also greatly reduce the engineering cost.The technology in the use of hydrostatic pile in pit to strengthen the foundation at the same time,the pile operation guide pit as a soil forced landing area,rectify the building with a certain construction sequence and strict monitoring.In this paper,the basic principle,design method and construction technology of the method are analyzed in detail.The main achievements are as follows:1.This paper summarizes the research status and classic cases of reinforcement technology at home and abroad.The main reasons for the incline of the building and the commonly used reinforcement rectification method is summarized.2.The influence of the excavation on the deformation of the surrounding foundation is analyzed by the cylindrical expansion theory.The calculation of settlement difference,the settlement rate control,the position of the pit and so on are analyzed.According to the characteristics of the pile underpinning,creatively put forward the concept ofunderpinning rate,in order to slow down the settlement rate.3.Using ABAQUS software,the model of 35 different pit depths and widths was established,and the influence of foundation excavation on foundation settlement was analyzed.The influence range of the foundation pit,the settlement difference between the two ends of the foundation,the discipline of the depth and width of the guide pit on the settlement of the foundation are obtained.It is found that the width of the guide pit is an important factor affecting the settlement of the foundation.The reasonable width of the guide pit is 1/4 of the width of the foundation,which provides suggestions for the construction of the guide pit size.4.Combined with the reinforcement structure of a bottom frame structure in Hanzhong City,the reinforcement of the project is carried out by using the the reinforcement technology of guide pit excavation based on pile underpinning.This paper analyzes the reinforcement mechanism of the rectification method,specific methods of design and construction.By adjusting the underpinning rate in the construction to achieve the purpose of effective control of the settlement rate,ensure the success of correction and the main structure of the security.Using the method proposed in this paper to strengthen the foundation of the building bearing capacity,recovery slope to 1.22 ‰.The success of the rectification work is proved to be a reliable and effective method to solve the inclination of the building.It can provide theoretical and practical reference for similar projects.