Experimental Study On Static And Dynamic Behavior Of Coarse Grained Filling For Heavy Haul Railway

Abstract:Heavy haul railways embankment accounted for a significant proportion, generally more than70%. As a heavy haul railway substructure, embankment not only withstand the weight of the upper structure of the line, but also withstand repeated loads of train.Coarse-grained soil is core filler of heavy haul railway embankment, but the study of its dynamic properties under repeated loads of train was very few.This article relies on National High Technology Research and Development Program863and enterprise technology innovation projects. The basic physical properties tests has been made for coarse filler of Shuo Huang heavy haul railway embankment analysing how the confining pressure、moisture content and degree of compaction may influence the the static and dynamic strength of coarse grain filling and the plastic deformation Finite element models has been made to analyse how the hydrostatic confining pressure and the air confining pressure.may influence static and dynamic three triaxial test results.The main research work and conclusions are as follows:(1)River sand and gravel combined with Shuo Huang railway site fine-grained soil has been selected for formulating A group of filling. Optimum moisture content and the maximum dry density has been obtained.(2)Large specimens sustained vibration test systems under specified confined pressure(LSSV) has been made by using MTS hydraulic servo instrument and conventional large-scale triaxial.This system solved the deficiency of conventional triaxial which could not do continuous vibration test under small confining pressure. Dynamic triaxial tests has been made by this system under different confining pressure, degree of compaction, moisture state.(3)Shear strength of coarse particulate filler under different conditions has been analyzed.Duncan-Chang model parameters.has been obtained and the parameters has been studied by comparation.(4)Researches on how the confining pressure, degree of compaction and moisture status under cyclic load affect cumulative axial deformation has been made. And corresponding variation of dynamic strength and its indices has been studied. The cumulative strain curves has been divided into three types:stable, destructive, critical type. Dynamic stress ratio R and critical dynamic stress ratio Rf has been defined. Researches on how the confining pressure、degree of compaction and moisture status affect critical dynamic stress ratio has been made.(5)Modeles has been made by using ABAQUS finite element program to analyse how the hydrostatic confining pressure and the air confining pressure. may influence static and dynamic three triaxial test results.Research results can be used for reference and use of dynamic deformation stability evaluation on heavy haul railway embankment core layer and embankment design based on dynamic deformation control.