Monitoring And Numerical Simulation On Anchor Supporting Structure Deformation Of Ultra Deep Foundation Pit

Since 1980,the pace of development of Chinese construction industry continues to accelerate,and the trend of the foundation pit engineering’s development is bigger and deeper in size and depth.Pile-anchor retaining structure has strong applicability,it is one of the supporting structures which are used most currently in the actual project.While the applications of this structure is increasing in the ultra-deep excavation engineering,but the study in this field is still in poor phase.Aiming at the actual situation,it monitors and uses ADINA software combined with the outstanding advantages of finite element numerical analysis method in the calculation of structure deformation to establish a plane model,which is based on Shenyang Mukden Financial Plaza with ultra-deep foundation pit,and simulates the excavation and support of process by means of the cell-death technology.At first,it analyzes the data of monitoring including the displacement of the pile top,the force of the prestressed bolt and the settlement of the building and pipeline surrounding the pit,then it verifies the applicability of ADINA software in ultra-deep pit by comparing simulation results and experimental results.Then it analyzes and summarizes the variation of internal forces and displacements of the supporting structure under different influence factors,including the length of the supporting piles,pile diameter and pile spacing,prestressed bolt,heaping level,heaping distance from the pit edge and heaping width,and obtain displacement curves,bending moment curves and shear curve at these factors changing.After the comparative analysis found that it can effectively control the displacement of the supporting piles by increasing prestressed bolt,while the displacement of the retaining piles can also be reduced by reasonable layout of the pit load,the effect on reducing displacement is small by increasing the length of pile when it meet the requirements of bearing capacity,and the change of the pile diameter and the spacing between the piles has little effect on the displacement of the retaining piles,but it can make the distribution of internal force more reasonable along the pile body.It is hoped that the results of this study will provide reference for actual engineering design and construction.