Numerical Simulation Analysis Of Double Row Pile-Prestressed Anchor Cable Supporting Structure

In the process of rapid development of theory and practice about foundation pit engineering,more and more forms of foundation type gradually appear.Since the end of last century,the pile anchor support structure and row pile support structure have been widely used in foundation pit engineering,which can effectively control the deformation of foundation pit.The double row pile prestressed anchor cable support system combines the advantages of two kinds of support forms,has been widely used in recent years.Because of the complexity of deep foundation pit,there are many problems remain to be studied.This paper takes a deep foundation pit project with double row piles and prestressed anchor cable support structure as the research background based on the summarizing the research results,and uses the general finite element software,the corresponding three-dimensional finite element model is established to simulate the mechanical performance of the support structure in the construction process,and obtain this kind of support structure by analyzing the deformation and internal force of the support structure in the construction process.The following research work has been carried out:Firstly,based on the research status at home and abroad,summary the load calculation method and internal force and displacement calculation method of foundation pit support;Secondly,based on the process of a large-scale deep foundation pit in China,the finite element model is established and numerical simulation is carried out,with the excavation of the soil during the construction of the foundation pit,the bending moment of front and back piles increases gradually.The construction of prestressed anchor cable effectively reduces the bending moment of front piles caused by the excavation in the previous step,which shows that prestressed anchor cable can effectively improve the stress of front piles;In the process of foundation pit construction,the amount of soil settlement in the rear increases gradually,and the settlement curve is spoon shaped distribution.When it is about 15 m away from the edge of foundation pit,the settlement value reaches the maximum,and then it is smaller and smaller from the edge of foundation pit,and the settlement amount decreases gradually;Finally,in order to further study the key design parameters affecting the double row pile prestressed anchor cable support system and provide relevant suggestions for the actual engineering design,under the condition of keeping other key parameters of supporting structure unchanged,the influence of key parameters on supporting structure is studied by changing pile distance,pile diameter,prestress of anchor cable and inclination of anchor cable.The results show that the influence of pile diameter and prestress of anchor cable on supporting structure is obvious.