冻融循环作用下土石混合体水热传输及冻融特性研究

Study on Characteristics of Hydro-Thermal Transfer and Freezing-Thawing of Soil-Rock Mixtures

冻融循环中含石率是影响土石混合体水热传输及冻融特性的关键因素之一。为研究冻融循环对土石混合体水热传输及冻胀融沉规律的影响,试验选用青藏粉质黏土与砾石组成的不同含石率(10%、25%、40%)的土石混合体为研究对象,进行10次单向冻融循环试验。结果表明:冻融循环中土石混合体的温度及未冻水含量的差异性与含石率具有强相关性,随着含石率的增大,土石混合体完全冻结的时间延长,未冻水含量变化速度降低;埋深的不同主要影响土石混合体的温度传输,进而影响试样的未冻水含量。对于含石率为10%、40%的试样,位移变化表现为冻结时的收缩和融化时的膨胀,试样冻结时的收缩率随含石率的增大而减小。

The rock content in freezing-thawing cycles is one of the key factors influencing the hydro-thermal transfer and freezing-thaw transferring characteristics of soil-rock mixtures.To study the effect of freezing-thawing cycles on hydro-thermal transfer,frost heave and thawing settlement of soil-rock mixtures,the soil-rock mixtures composed by Qinghai-Tibet silty clay and gravel with different stone content ratios(10%,25%,40%)were selected as research objects,and 10 unidirectional freezing-thawing cycles were conducted.The results indicated that the differences in the temperature and unfrozen water content of soil-rock mixtures during the freezing-thaw cycles had a strong correlation with the rock content.With an increase in the rock content,the completely frozen time for soil-rock mixtures has been extended,and the variable rate of the unfrozen wate content decreased.The difference of buried depth mainly influenced the temperature transfer of soil-rock mixture,and had an indirect effect on the variation of volumetric unfrozen water.For the samples with stone contents of 10%and 40%,the displacement change was manifested as shrinkage during freezing and expansion after thawing,and with an increase in the stone content,the shrinkage of specimens during freezing tended to decrease.