黑龙江漠河段粗砂土冻胀性试验研究

Experimental study on frost heave of coarse sandy soil in Mohe section of Heilongjiang River

冻胀灾害是季节性冻土区建筑工程中常遇问题,为研究黑龙江漠河段流域粗砂土冻胀特性,取该流域河漫滩粗砂土,采用试验规范中规定温度控制模式和有侧限单向冻结方式,对不同含水率和干密度粗砂土开展冻胀试验。结果表明,在粗砂土冻胀试验中,粗砂土冻结过程主要分为4个阶段:过冷阶段、温度突变阶段、孔隙水结晶阶段和稳定冻结阶段,粗砂土起始冻结温度为-0.19℃。在冻结过程中探究粗砂土试样内部温度场和温度梯度随时间发展规律,温度梯度随时间推移逐渐增加。在各试验条件下粗砂土冻胀率均小于1%,黑龙江漠河段流域粗砂土属于冻胀不敏感土类。在试验范围内,粗砂土冻胀率随试样含水率增大而增大,随试样干密度增大而增大,粗砂土冻胀率与干密度和含水率呈线性关系。

Frost heaving disaster is a common problem in the construction engineering of seasonal frozen soil area. In order to study the frost heaving characteristics of coarse sandy soil in Mohe section of Heilongjiang River, the flood plain coarse sandy soil in the basin was taken and the temperature control mode specified in the test specification and the unilateral freezing mode with side limit were adopted to carry out the frost heaving test on coarse sandy soil with different moisture contents and dry densities. The results showed that the freezing process of coarse sand was divided into the following four stages: supercooling stage, abrupt temperature change stage, pore water crystallization stage and stable freezing stage, and the initial freezing temperature of coarse sandy soil was-0.19 ℃. In the process of freezing, the development law of temperature field and temperature gradient in coarse sand samples with time was studied. The freeze-heaving rate of coarse sandy soil in Mohe section of Heilongjiang River was less than 1% under all the test conditions. Within the test range,the frost heaving rate of coarse sandy soil increased with the increase of sample moisture content, and with the increase of sample dry density, the frost heaving rate of coarse sandy soil had a linear relationship with dry density and water content.