Study On Mechanism Of Lime Improvement Of Expansive Soil Subgrade

With the development of national economy and the construction of national infrastructure.In a large number of construction projects will encounter a variety of serious technical problems,including the construction of the railway subgrade,the expansion of the land area of the embankment there is a greater potential for stability risks.Therefore,in the expansion of the land area or when the natural resources are limited by the need for expansive soil as roadbed filling material,it is necessary to expand the treatment of expansive soil and the formation of improved soil.The study on the constitutive relationship of expansive soil solution and modified mechanism of quantitative analysis and the improved soil,expansive soil subgrade of expansive soil area development processing and ensure the roadbed after construction safety is of great significance.In this paper,taking the construction of Expansive Soil Subgrade of Qianjiang railway extension project from the new door to the Xiantao railway as an example,the main research contents are as follows:(1)the lime and other material modified expansive soil improved mechanism,mechanism of improvement are analyzed,the advantages and disadvantages of various improved methods,the reaction,the formation process and the local construction of environmental resources conveniently utilizing situation comprehensively discusses improvement process,determine the expansive soil foundation,using lime to study the improvement of expansive soil.(2)the related properties of lime and its action mechanism and performance in the modified expansive soil.The effect of lime ratio and water content on the compaction test density of expansive soil was studied by single factor experiment.Lime ratio and moisture content influence the adsorption of methylene blue on Determination of montmorillonite content change of lime and water content were explored by single factor experiment,the mechanism of soil lime improved expansive detailed quantitative analysis.(3)through the single factor experiment,the influence of the curing time on the shear strength index of the modified expansive soil was studied.The analysis obtained in consideration of curing period and different density conditions of expansive soil improved by orthogonal experiment the optimum ratio,also reasonably determine the major factors in the formation of expansive soil strength in different factors and secondary factors,should pay attention to the main control factors of expansive soil subgrade construction,using reasonable control of minor factor.(4)three triaxial test of modified expansive soil stress-strain constitutive relation study on deformation characteristics and damage mechanism of lime treated expansive soil,the Duncan Chang model to describe the brittle failure before showing pressure hardness,shear contraction and strain hardening,the calibration of model parameters.The calculation parameters for numerical computation.