Finite Element Analysis And Sability Characteristics Analysis Of Excavation

With the rapid development of economy and society, the construction of large engineering facilities, excavation stability has been a hot and difficult research. On the basis of the Beijing Xinxinyuan engineering, the Hardening Soil model in PLAXIS is used to analyse the whole process of deep foundation excavation. It focuses on analysing of deformation about pit-retaining and stability about foundation, including the soil uplift at the bottom of foundation, the deformation of pile and the soil subsidence about surface, according to the numerical simulation results compared with the actual monitoring data, which proved the practicality of PLAXIS finite element software At last the "Li Zheng" deep foundation pit design soft was used to analyze the stability of the foundation pit design.We commpared the results between PLAXIS and Lizheng on the horizontal displacement of the pile and the subsidence of the backfill soil. Then, we disscussed the reasons for different results in horizontal displacement deformation.The main works and conclusions are as follows:(1) This paper analyzes the basic principles of excavation design, discusses the three main methods of excavation design (limit equilibrium method, elastic resistance method and finite element method) advantages and disadvantages, and summarizes some of the excavation scope of design methods for doing excavation designed to provide reference.(2) This paper introduces MC and HS models in PLAXIS software, and the whole process is simulated, which uses HS model for foundation pit excavation retaining, and the numerical simulation results and existing monitoring data to do a comparative analysis proved that the method used in this paper and the finite element analysis is correct and rationality.(3) When the upper part of the foundation pit using soil nail walls, the law of the bottom soil uplift was summarized, and then analyzed the characteristics and mechanism of soil nail walls.(4) When the foundation pit which was excavated by step using anchored piles, the deformation of the pile displacement, bottom soil uplift and the pile moment were analysed for engineering reference. The effects of different prestressed on deformation of the pile were simulated.(5) In this paper, the stability of the foundation pit was verified by Lizheng software, and we commpared the results between PLAXIS and Lizheng on the horizontal displacement of the pile, and then compared and analyzed simulation results and the actual monitoring data.