Stability Analysis Of The Bottom Of Shanghai-Kunming High-speed Railway Tunnel

In the 13 th Five-Year Plan of China,the transportation infrastructure is in a stage of steady development,Railway construction is certainly an important part of development,The Shanghai-Kunming high-speed railway is one of them.Deformation at the bottom of the tunnel on the railway is a relatively common disaster,which has a greater impact on train operations.For such problems,in-depth research is needed to find out the root cause and solve it.The analysis of the mechanism of the uplift deformation of the bottom structure of the tunnel requires more and more complex factors.The swelling rock formation is one of the reasons.The current solution to this problem still lacks a sound basis for mechanical analysis.Therefore,it is of great significance to study the uplift deformation of the bottom structure of high-speed railway tunnels and the corresponding solutions.This article first investigates and analyzes cases of railway tunnels that have been deformed due to bottom uplift at home and abroad,then,with the Shanghai-Kunming High-speed Railway and Gangwu Tunnel as the background,The swelling rock is analyzed through tests and numerical simulations,and compared with the actual investigation and monitoring,and then come to the corresponding conclusions:(1)Find out by collecting data and papers,the analysis of the development history of swelling rock tests and the analysis of the main causes of the uplift at the bottom of the tunnel are presented.There are mainly the nature of the surrounding rocks,the characteristics of the Indus arch,and other external factors.(2)Gather geology and hydrological data on the Gangwu Tunnel on the Shanghai-Kunming high-speed railway,according to the survey report of the Gangwu Tunnel of China Railway Second Institute,the related causes of the disease were initially drawn.The lithology and depth of rock formations at the bottom of Gangwu Tunnel were sampled by drilling.(3)Indoor experiment of remodeling the removed rock sample,Free-expansion rate test,no-load limit inflation rate test,expansion force test and disintegration test,we can know the maximum free expansion rate was 44.7%;The unfolded non-loaded expansion rate gradually decreases with the increase of the moisture content of the sample,and gradually increases with the increase of the sample density;In the two groups of specimens with water content of 5.31% and 8.99%,the swelling force increased with the increase of the specimen density,the maximum expansion force is 119.24 kPa,and the greater the moisture content of the sample,the smaller the corresponding expansion force;Five of the 11 samples disintegrated and montmorillonite content exceeded 9%,it is obvious that the greater the content of montmorillonite is,the greater the impact on rock disintegration occurs.Finally,preliminary judgment of partial rock samples with weak expansion.(4)Finding rock-related parameters based on indoor test data,numerical simulation using finite element software ANSYS,it is concluded that the vertical displacement at the bottom of the tunnel increases with the increase of the thickness of the expanded rock,and decreases with the increase of the buried depth of the expanded rock,As the radius of curvature of the inversion arch increases,it decreases as the thickness of the inversion arch increases.