Analysis Of Deformation Law Of Adjacent Buildings Caused By Foundation Pit Excavation-dewatering

With the acceleration of urban modernization,the urban population is more and more dense,and the per capita available land is increasingly tight.In order to alleviate this situation,an increasing number of people are using underground spaces and various skyscrapers.As the density of buildings increases rapidly,the city’s reinforced concrete forests are becoming more and more magnificent..In such an environment,the impact of deep foundation pit engineering on adjacent buildings is an inevitable practical problem.This kind of foundation pit engineering is easily restricted by the nearby terrain and buildings.In such a construction environment,the excavation,precipitation and support of foundation pit need to be improved Therefore,it is necessary to study the influence of deep foundation pit excavation dewatering on adjacent buildings be imperative.This paper studies the deformation of retaining structure and building in the process of deep foundation pit excavation and dewatering,analyzes the deformation laws of buildings under different working conditions,and puts forward reasonable reference suggestions for this kind of deep foundation pit engineering.Firstly,the excavation deformation mechanism and precipitation deformation mechanism of the foundation pit areanalyzed,the combination of regional geology and support features establishes a numerical model with reference values to simulate distance,location of buildings,excavation and dewatering process of foundation pit in different situations.And then,the Midas GTS NX finite element analysis software isused to model the existing actual engineering,and the surface settlement around the foundation pit and the deformation law of the top of the retaining structure in the specific construction process are obtained.Analyze the model data,and compare with the actual project.The main conclusions are as follows:(1)Due to the existence of building foundation,the settlement trend of building is different from that of original ground surface(without building),which is not simply superimposed effect.When the building near the foundation pit is in the main settlement area,the foundation deformation is significantly affected by the foundation pit excavation dewatering.(2)According to the change of building location,the sensitivity of different positions of foundation pit to adjacent buildings is different.The middle part of foundation pit boundary is the most sensitive,followed by the outer corner,and the inner corner is the least sensitive.(3)It was found that changing the order of excavation and dewatering of deep foundation pits has a great impact on the deformation of foundation pits and buildings.Hierarchical excavation and dewatering has a significant effect on reducing the deformation of foundation pit and adjacent buildings.In deep foundation pit engineering,the method of one-time dewatering to the bottom and then excavation should be avoided as far as possible.(4)By changing the embedded ratio of retaining pile,it is found that the change of embedded section length has better effect on controlling the horizontal position of the building than the settlement,and the efficiency of deformation control first increases and then decreases.(5)By comparing the simulation data with the measured data,it can be found that the simulation results are somewhat larger,but the deformation law remains the same,which can still reflect the interaction between the foundation pit and adjacent buildings during dewatering excavation.