重载铁路基床粗粒土填料的静力特性研究

Static Characteristic Research on Coarse Grained Soil Filling in Heavy Haul Railway Subgrade Bed

研究目的:粗粒土因其良好的工程力学性质,是重载铁路路基的核心填料,粗粒土填料在大轴重列车作用下的变形特性直接影响路基整体稳定及行车安全。静力特性研究是动力特性研究的基础,因此本文通过开展大型三轴剪切试验和有限元分析,对粗粒土填料在静载作用下的变形规律进行研究。研究结论:通过对粗粒土填料的静力特性研究得出:(1)饱和试样的应力应变关系呈现近似理想弹塑性,非饱和试样的应力应变关系属于应变软化型;(2)粗粒土填料的峰值剪切强度随着含水率的增加而降低,随着压实度和围压的增加而增大;(3)基床层路基中心线上正应变ε_y和变形U_y随着含水率的增加而增加,随着压实度的增加而减小;(4)该研究成果可为我国重载铁路基床设计和养护提供参考依据。

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 shear 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 increase of moisture content, and increases with the increase of degree of compaction and confining pressure. （3） Normal strain εy and deformation Uy at center line of subgrade bed increase with the increase of moisture content, decrease with the increase of degree of compaction. （4） The research results could provide references for the design and maintenance of heavy haul railway subgrade bed.