Research On Long-term Arch Deformation Of Weak Subgrade Of High-speed Railway In Southwest Region

The red rock layer(referred to as the red layer for short)is a sedimentary layer of terrestrial debris(basin river and lake environment)with red as the main color in appearance;the color is mostly red,purple or brown red.The red beds in China are mainly distributed in the southwest,east,south and northwest regions.It has the characteristics of weak water permeability,strong hydrophilicity,softened rock mass after water immersion and easy disintegration after water loss.The red bed soft rock roadbed is very serious in the southwest region.The bad nature of the red bed soft rock often causes large deformation of the roadbed,and because the high-speed ballastless track is extremely sensitive to deformation,the deformation of the soft rock roadbed will affect the safe operation of high-speed railway Caused a great impact.At present,the reason for the deformation of the high arch of the railway foundation is attributed to the swelling of the soft rock,and few people analyze the problem of the arch of the subgrade from the perspective of rheology.In this paper,based on the arching problem of a ballastless track subgrade in the southwest region,using data research,theoretical analysis,numerical simulation and other methods,based on the analysis of rock mass creep characteristics,the research and selection of a suitable constitutive model The deformation rule of the soft roadbed in red layer under the rheological effect was explored.The main research contents of this article are as follows:(1)Consult relevant literature and theoretical analysis to determine the constitutive model describing the creep characteristics of soft rock,comprehensively understand the geological conditions and the distribution law of the soil layer in the area where the disease site is located,and establish the model in combination with FLAC3 D numerical simulation software for calculation.(2)Comparative analysis of numerical simulation results,the vertical and horizontal displacements,principal and minor stresses,and distribution of plastic zone of the elastoplastic and rheological constitutive models.(3)The rheology of the subgrade rock mass is stable rheology,that is,with the development of time,although the deformation changes with time,after the transition creep stage,the creep rate gradually decreases to infinitely close to 0 The deformation eventually approaches a certain fixed value,and the rock mass will not be destroyed due to rheology.