人工冻结粉质粘土正冻过程中水分迁移室内试验研究

摘要

For the purpose of studying water migration rule and temperature distribution character of silty clay,use one-way freezing water migration tester and low-temperature test chamber to conduct test for one-way freezing water migration indoor of Lanzhou silty clay.The test soil sample used man-made Lanzhou loess,which liquid limit is 33% and plastic limit 19.5%.The diameter of sample is 10 cm,the height 21 cm;the initial water content is 13.4%,18.1% and 24.6%,dry density is 1.27 g/cm3 ,1.40 g/cm3 and 1 .5 3 g/cm3 ,the different temperature difference 7 ℃,9 ℃ and 1 1 ℃.We conduct 7 test works under different boundary conditions,testing one-way freezing water migration and temperature distribution prop-erty of sample in close system.The result shows that,in some range,the inside wall exists crack which has ice lenticle.The freezing temperature difference has obvious effect on freezing depth of sample,and the big-ger the difference,the more water migration amount.As far as ice (water)content peak,when the differ-ence is little,the peak is big.The water migration amount is obvious and peak of ice (water)content is big when dry density is low.When initial water content is less than liquid limit,the more water migration,the higher the initial water content.%为研究粉质粘土在冻结过程中水分迁移规律及温度分布特性,采用单向冻结水分迁移试验仪及低温试验箱,对兰州粉质粘土进行了室内单向冻结水分迁移试验.试验土样采用人工制备兰州黄土,液限33．0％、塑限19．5％.试样直径为10 cm、高度21 cm；试样的初始含水率分别为13．4％、18．1％、24．6％,干密度分别为1．27 g/cm3、1．40 g/cm3、1．53 g/cm3,不同温度差为7℃、9℃、11℃.在不同边界条件下进行了7组试验工作,测试了试样在封闭系统中单向冻结水分迁移及温度分布特性.试验结果表明,试样一定范围内侧壁存在裂缝,裂缝处存在冰透镜体.冻结温度差对试样冻结深度的影响最为明显,温度差越大水分迁移量越大.但就含冰(水)量峰值而言,温度差较小时峰值较大.干密度较小时水分迁移量较明显,含冰(水)量峰值较大.当初始含水率小于液限时,初始含水率越大,水分迁移量也越大.