Monitoring And Numerical Simulation Analysis Of A Deep Foundation Pit Support In Shenyang

As the urban modernization process continues to accelerate,a large number of people flock to the city,and the space on the ground is increasingly compressed.This has led more and more cities to begin to develop underground space,and deep foundation pit engineering has gradually increased.Reasonable choice of support scheme and reliable and stable supporting structure is the key to the safe construction of foundation pit engineering.The construction of the deep foundation pit support project not only directly affects the safety of the project,but also has a huge impact on the surrounding environment.Based on the deep foundation pit engineering in Shenyang,this paper combines the on-site monitoring,theoretical analysis and numerical simulation of the foundation pit support structure to carry out the stability and safety of the supporting structure system during the construction of deep foundation pits.In-depth research,the main research contents are as follows:(1)According to the hydrogeological conditions of the project,a monitoring plan combining information automation and on-site inspection is developed for the foundation pit project.It can accurately and quickly feedback the dynamic information of the structural changes of the support structure,and provide security for the construction of the foundation pit.(2)According to the analysis of the deformation monitoring data of the support pile,the maximum deformation position occurs in one-half of the pile body,and the deformation is about 9 mm,which accounts for 56% of the monitoring and warning value,indicating the design of the support structure.The solution is safe and reliable.(3)During the excavation of deep foundation pits,the deformation of the supporting structure presents two rules: from the "cantilever forward" to the "bow-shaped two sides small intermediate large" deformation,it can be seen that the deformation of the supporting structure has Time and space effect.(4)The axial force of the same vertical three steel supports in the strip foundation pit support structure increases with the depth of the foundation pit construction process,and the axial force value changes stepwise,and the foundation pit excavation can be found.Nearby steel supports have the greatest impact.The factors that have the greatest influence on the axial force and stability of the steel support are the foundation pit width and the excavation method.(5)Comparing the monitoring data with the simulation data,it is found that they are in good agreement with each other,which indicates that the parameters of the model are selected reasonably,which proves that the Midas/GTS simulation software can provide reference for the design and construction of similar foundation pit supporting engineering.(6)Comprehensive analysis of the monitoring and simulation data reveals that under the joint action of the supporting structure and the steel support,there is a coordination relationship between the deformation of the supporting structure and the axial force of the steel support,and the deformation of the supporting structure is effectively limited by the supporting structure.When the steel support pre-addition shaft is applied to 60% of the design value by simulation,the steel support has the best effect on the deformation control of the support structure.