Researrch On Deformation Of Foundation Pit And Adjacent Buildings By Foundation Pit Excavation

In recent years,due to the rapid increase in the domestic population and the rapid development of the national economy,in addition to remote areas such as Xinjiang and Tibet;the land resources in other parts of the country have becom e scarcer.In order to save land resources,the development trend of the city will gradually develop to high altitude and underground,from high-rise and super high-rise buildings to urban subway construction and urban integrated pipe corridor construction.Therefore,the research of deep foundation pit engineering has gradually become a hot topic,which is not only related to engineering quality problems,but also closely related to life and safety issues.In this paper,the deformation principle of foundation pit and building structure is taken as the entry point by foundation pit construction,and a deep foundation pit project in Xi'an is taken as the engineering case.The project uses pile anchor support method on the north side and west side of the foundation pit.Soil nailing walls are used elsewhere.Secondly,the combination of numerical analysis and construction monitoring data is used to analyze the specific characteristics of foundation pit and building structure deformation,and the effects of parameters such as pile diameter,pile length and prestress on foundation pit and building are studied.The main works and conclusion are as follows:(1)The chart analysis method is used to visually reflect the real-time change of the site monitoring data.According to the chart,it can be seen that the settlement values of the various structural points of the building structure are different in the construction stage,and the maximum settlement value does not exceed the control value.Meet the design requirements.(2)The numerical analysis method is used to simulate and analyze the dynamic process of foundation pit construction,and the deformation results of the horizontal displacement of the foundation pit caused by building settlement and excavation are obtained.The results show that the settlement value of the foundation near the CJ5 point of the building is the largest,and the location of the building is the most sensitive area of surface settlement.Comparing the simulation results with the monitoring results,it is found that although there is a certain deviation between the monitoring data and the simulation results,the overall trend changes consistently.It can be seen that the numerical simulation method can truly simulate the deformation of the foundation pit.(3)Adjust the parameters such as pile diameter and pile spacing,and explore the influence of various parameters on the deformation of foundation pit and building foundation.It is found that the variation of pile spacing within the set value has little effect on the foundation settlement.(4)Orthogonal design is used to analyze the pile diameter,pile length,anchor cable prestress and upper load of building foundation by orthogonal design method.It is found that the vertical load deformation of the upper part of the building foundation is vertical deformation of the foundation.The impact is most obvious,followed by anchor cable prestress and pile length,while pile diameter changes have the least impact on building settlement.