Analysis Of The Influence Of Foshan Soft Soil Deep Foundation Pit Construction On Adjacent Buildings

The construction of urban underground space is tied closely with the foundation pit engineering,most of which are located in the prosperous area.Their construction will have a great impact on surrounding buildings.The southeast coastal areas are mostly soft-soil areas,where the groundwater level is high and the soil has the characteristics of low strength,high water content,poor permeability and high compressibility.Under this condition,the impact of foundation pit construction on adjacent buildings in soft soil and water rich areas is greater.Therefore,it is of great significance to study the deformation control of foundation pit retaining structure,surrounding soil layer and adjacent buildings.Based on the deep foundation pit project of Dongle Road Station of Foshan Metro,through field data investigation,construction process monitoring and numerical simulation,this paper focuses on the deformation law and causes of retaining structure,surrounding soil layer and adjacent building pile foundation caused by foundation pit dewatering and excavation.By controlling the water level outside the pit,the paper studies the influence of different water levels outside the pit on the excavation of foundation pit,and analyzes the sensitivity of diaphragm wall deformation,soil displacement,pile foundation displacement to the drop of water level outside the pit.The main research work is as follows:(1)By monitoring the construction site of the foundation pit of Dongle Road Station of Foshan Metro and sorting out the field monitoring data,the paper analyzes the laws of the water level change outside the pit,the deformation of the retaining structure,the settlement of the surrounding surface and the settlement of the adjacent buildings,and the relationship between them and the excavation depth of the foundation pit also gets specified.(2)Considering the regional engineering geological and hydrological conditions and construction conditions of Dongle Road station,the paper establishes a two-dimensional numerical model by using the finite element software with the middle section of Changfa Building as the section.The rationality and reliability of the two-dimensional numerical model are determined by comparing and analyzing the field monitoring data and simulation results.And this paper also analyzes the horizontal displacement law of surrounding soil layer and the horizontal displacement and stress law of pile foundation are analyzed.(3)Based on the two-dimensional numerical model of foundation pit dewatering excavation,the paper builds two different models based on the high and low level variables of water level outside the pit.It also studies the influence of different water levels on the foundation pit and surrounding environment during excavation.In the paper,the sensitivity of the deformation of ground wall,soil displacement and pile foundation displacement to the groundwater level drop in the excavation process of foundation pit get careful analysis,which provides reference for similar projects.