严寒地区路基CFG桩冻胀破坏机理研究

Study on Frost Heave Failure Mechanism of Subgrade CFG Pile in Severe Cold Area

严寒地区铁路路基工程根据地质情况,部分软基段落设计有CFG桩。根据建设单位对以往工程的相关经验,为防止CFG桩在越冬期间出现冻胀导致断桩,需对CFG桩进行覆盖保温。但该做法对冻胀作用于CFG桩破坏的理论依据不足,且覆盖保温法需增加大量的投入,同时在进行覆土保温时易对CFG桩造成扰动破坏。为充分研究冻胀作用对CFG桩的影响,论文通过对CFG桩的外部环境进行受力分析计算,明确了土壤冻胀时不同作用力对CFG桩质量的影响程度,并通过现场验证,明确了CFG桩浅层断桩与冻胀作用之间的关系,对严寒地区的CFG桩越冬施工具有一定的指导意义。

According to the geological conditions of railway subgrade engineering in severe cold regions,CFG piles are designed in some soft foundation sections.According to the construction unit's relevant experience of previous projects,in order to prevent CFG pile from breaking due to frost heaving during overwintering,it is necessary to cover the CFG pile for insulation.However,the theoretical basis of frost heaving on the damage of CFG pile is not enough,and the covering insulation method needs to increase a lot of investment.At the same time,it is easy to cause disturbance and damage to CFG pile in the process of covering soil insulation.In order to fully study the influence of frost heaving on CFG pile,the paper analyzes and calculates the external environment of CFG pile,clarifies the influence degree of different force on CFG pile quality during soil frost heaving,and through field verification,clarifies the relationship between CFG pile shallow broken pile and frost heaving,which has certain guiding significance for CFG pile overwintering construction in severe cold area.