The Analysis Of Foundation Pit And Surrounding Environment Monitoring Of Shanghai Complex Projects

With the rapid development of the urban scale,the increasing tension of land resources,it is enforced to expand the space of the underground.Especially to the city,the deep foundation pit engineering,dense roads and bridges,transportation pipelines,existing buildings and civil air defense projects nearby.Although the temporary construction,its technical complexity is far from the permanent structure and the upper structure can be compared.If not pay attention in the process,it will not only endanger the safety of the deep foundation pit itself,but also bring the future project buried potential safety problems.Some will even bring disaster to nearby roads and bridges,structures and underground facilities,resulting in huge losses.Therefore,the construction requirements of the foundation pit are more and more strict,especially in the construction process of the foundation pit envelope and the surrounding environment observation.Dynamic monitoring can truly reflect the deformation of foundation pit construction process.It can help the construction side to understand the effect of construction and ensure the construction pit safety.This paper analyzes the main characteristics of foundation pit engineering and points out the existing problems and development trend of foundation pit construction in China.On this basis,the paper puts forward the main contents,methods of the paper and the significance of the research.Based on the project of Shanghai urban complex foundation pit engineering,the construction scheme,supporting system and surrounding environment of foundation pit are expounded and the monitoring scheme of construction safety and surrounding environment impact of foundation pit engineering of Shanghai urban complex project is discussed.The time-history curves of horizontal displacement,surface subsidence,supporting axial force,vertical displacement and groundwater level with time are plotted by arranging the monitoring data.The monitoring data of each monitoring project are analyzed and summarized respectively.The results of field monitoring show that the horizontal displacement of supporting structure is closely related to the depth of foundation excavation and the position of inner support during excavation.During the excavation of the foundation pit,the surface has certain settlement changes and the surface subsidence presents a certain spatial effect.The settlement of the middle part of the pit is larger and the settlement of the sides is smaller.The settlement of the top of the slope is larger than that of the top of the wall and the surrounding area.The results of the overall settlement monitoring show that the surface subsidence and the building settlement did not exceed the warning value during excavation.The dynamic monitoring of foundation pit construction can effectively ensure the safety of foundation pit engineering.