Numerical Analysis And Optimization Design Of Pile-Anchor Retaining Structure For A Deep Foundation Pit

With the increasing height of the building,it is more important to study the theory and design calculation of deep foundation pit support.The pile-anchor support structure can not only effectively limit the displacement of deep soil,but also reduce the possibility of sliding failure of soil.Can also reduce the cost,save the project cost.Therefore,it is widely used in foundation pit supporting engineering.This paper,taking a deep foundation pit engineering in chongqing as an example,according to the distribution of soil layer and mechanical parameters,the use of reason is the deep foundation pit design software on the west side of the foundation pit supporting design,and obtained the shear force curve of double row piles,closed curve of horizontal displacement of foundation pit,soil around the settlement curve and earth pressure distribution law;Then Midas/GTS finite element software was used to build a three-dimensional model,and the foundation pit under the pile-anchor support composed of double rows of piles and anchor cables was simulated and calculated,and the stress and displacement curves of the excavation process were obtained.Finally,by comparing the theoretical calculation values,monitoring values and numerical analysis results,the optimization design scheme of foundation pit support is proposed.The main research results are as follows:(1)According to the standard formula,the Lizhengshen foundation pit design software is used to calculate the displacement,bending moment and shear force of the supporting structure of the west road of the foundation pit under various working conditions,and the basic law of the foundation pit supporting deformation under various working conditions is analyzed and obtained.(2)Through numerical simulation,the horizontal displacement of foundation pit,the displacement of supporting pile,the stress condition and the settlement of foundation pit are obtained.(3)The numerical analysis results were compared and analyzed according to the calculation results of the standard formula and the field monitoring data,and the design parameters of the M method formula were optimized.By increasing the calculation method of active earth pressure between piles,the calculation method was closer to the engineering practice.The optimization design scheme of deep foundation pit support is put forward,and the rationality of the designed support scheme is proved,It has a certain reference value for similar projects.