考虑补水条件的长白铁路路基土冻胀特性试验研究

Research on Frost Heave Characteristics of Subgrade Soil of Changchun-Baicheng Railway Considering Water Supply

水作为季冻土发生冻胀的主要条件之一,对土体的冻胀特性有显著影响。本文选取长白铁路扩能改造工程CBSG-3标段沿线不同路基土样,基于开放系统下的室内季冻土冻胀试验,开展-15℃下的单向冻结补水试验,探究不同土样在饱和补水和非饱和补水工况下的冻胀特性。结果表明,不同土样冻胀量发展大都经历三个阶段:快速增长—缓慢增长—保持稳定;土样本身含水率和外界水源都可显著增加土的冻胀率,在饱和补水与非饱和补水工况下,淤泥质粉质黏土冻胀率最大分别为38.8%、31.2%,粉砂土的冻胀率最小分别为21.7%、11.1%。基于研究结果,制定不同路段的路基防冻胀措施。

Water is one of the main conditions for frost heave of seasonal frozen soil,which has a significant impact on the frost heave characteristics of the soil.This paper selects different subgrade soil samples along the CBSG-3 section of the Changchun-Baicheng Railway Expansion and Reconstruction Project,based on the indoor environment under the open system.In the seasonal frozen soil frost heave test,a one-way freezing water supplement test at-15℃was carried out to explore the frost heave characteristics of different soil samples under saturated and unsaturated water supplement conditions.The results show that the development of frost heave of different soil samples generally goes through three stages:rapid growth-slow growth-maintaining stability;the moisture content of soil samples and external water sources can significantly increase the frost heave rate of soil.Under water supplement conditions,the maximum frost heave rates of silty clay are38.8%and 31.2%,and the minimum frost heave rates of silty sand are 21.7%and 11.1%,respectively.Based on the above analysis,measures for frost heave prevention of subgrades in different sections are given.