Abstract:Abstract:Research purposes: Coarse grained soil( CGS) is the core filling of heavy haul railway because of its good engineering mechanics properties, the deformation properties of CGS under heavy axle load train directly affect the subgrade stability and traffic safety. The static characteristic research is the foundation of dynamic characteristic research. Therefore,large - scale triaxial s!iear tests and finite element analysis were carried out to study the deformation properties of CGS under static loads. Research conclusions: Regarding the static characteristic research on CGS, the following conclusions can be drawn:(1) The stress - strain relations of saturated specimens and unsaturated specimens were the types of ideal elastic - plastic and strain soften characteristics,respectively. (2) The peak shear strength of CGS decreases with the in crease of moisture content,and increases with the increase of degree of compaction and confining pressure. (3) Normal strain ! and deformation ! at center line of subgrade bed increase witii the increase of moisture content, decrease witii the increase of degree of compaction. ( 4) The research results could provide references for the design and maintenance of heavy haul railway subgrade bed.