季节性冻土区铁路接触网立柱桩基础冻胀变形数值模拟研究

Simulation Study on Frost Heave Deformation of Railway Catenary Pile Foundation in Seasonal Frozen Soil Area

季节性冻土区铁路接触网基础常因土体冻胀影响,发生拔起、倾覆等工程病害,严重影响电气化铁路供电安全与平稳运营。为分析接触网基础受土体冻胀的影响过程,本研究基于热-力耦合理论,考虑土体冻胀正交各向异性、温度对路基土体冻胀率的影响等关键因素,选取川藏铁路沿线昌都、康定、理塘三地区全年气温变化条件,分析全年不同时期接触网立柱基础冻胀变形特征。结果表明:桩基整体呈现上拔、外倾趋势,桩基整体位移量与冻深呈现正相关关系,而冻深与全年气温条件显著相关。建议可以通过保温隔热等防护措施减小冻深,从而达到改善桩基冻胀变形,提高基础冻胀抗拔稳定性的目的。

The foundation of railway catenary in seasonal frozen soil area is often affected by soil frost heaving,which causes engineering disasters such as uplifting and overturning,which seriously affects the safety and smooth operation of electrified railway power supply.In order to analyze the influence of frost heaving on catenary pile foundation,based on thermal mechanical coupling theory,considering the influence of orthogonal anisotropy of frost heaving and temperature on the frost heaving rate of subgrade soil,the boundary conditions of annual temperature change in Changdu,Kangding and Litang were selected to analyze the frost heaving influence of catenary pile foundation in different periods of the year.The results showed that the overall pile foundation showed a trend of uplift and outward inclination,the overall displacement of pile foundation showed a positive correlation with the freezing depth of subgrade,and the freezing depth of subgrade was significantly correlated with the annual temperature conditions.It is suggested that the freezing depth can be reduced by thermal insulation and other protective measures,so as to improve the frost heave deformation of the pile foundation and improve the frost heave stability of the foundation.