FLAC-3D Based Numerical Simulation Analysis Of Deep Foundation Pit Support With H-type Double Row Piles

With the rapid development of China’s modern economy,in order to make better use of resource space,high-rise buildings begin to increase,people’s requirements for urban engineering construction gradually increase,land resources have become precious,and the requirements for the depth of foundation pit excavation are also higher and higher.As a result,the design of foundation pit support is becoming more and more difficult,and the problems of foundation pit construction are becoming increasingly prominent,so it is increasingly difficult to meet the stability requirements of foundation pit engineering.For example,underground buried objects such as subway,underground shopping mall or rock mass often lead to the fact that the double row piles used in engineering can not be of equal length.Therefore,in the field of geotechnical engineering,the new H-type double row pile has become a new breakthrough in the research of foundation pit engineering support.On the basis of previous studies,this paper takes the deep foundation pit engineering of a company’s training base in Guilin as the research background,combined with the actual survey data of the project,uses the frws9.0 software and FLAC-3D numerical simulation software of Tongji QIMINGXING deep foundation pit to analyze the stability and support design of the foundation pit.Among them,the paper focuses on the simulation and calculation of the combined support system of H-type double row piles with internal support,and makes a comparative analysis with the simulation of single row pile support structure.At the same time,through the numerical simulation analysis of foundation pit modeling,the whole excavation process is simulated and analyzed,and then compared with the actual monitoring data,it is found that there is little difference,so as to analyze the related role of H-type double row pile foundation pit support.The conclusions are as follows(1)according to the actual field investigation,the formation lithology,hydrogeology,physical and mechanical parameters of rock and soil,corrosion properties of groundwater and soil,etc.in the area where the project is located are obtained.finally,the section of section 6-6AB,which is the most representative section,is selected,and it is concluded that the joint design of h-shaped double-row piles and internal supports is more economical and safer than other supporting structures.(2)Selecting a most representative section,it is concluded that the joint design of H-type double-row piles with internal bracing is more economical and safe than other supporting structures.(3)The FLAC-3D numerical simulation method is used to carry out numerical simulation analysis on three kinds of pit support methods,namely,no support,single row pile and H-shaped pile.It is found that compared with single row pile support,H-shaped double row pile can not only meet the stability requirements of the foundation pit,but also meet the influence of the actual situation(4)project monitoring,according to the results of numerical simulation of horizontal displacement in conformity with the actual engineering monitoring data,the horizontal displacement of the actual maximum displacement to simulate vary by 0.28 cm,0.031 cm from the vertical,further verify the h’s support of foundation pit supporting design with double-row piles on the stability of foundation pit and the deformation of foundation pit displacement has played a vital role,and the means of the dynamic simulation,can make the simulation more close to the actual situation of engineering mobile.