双向冻结单向融化土冻融循环下的融沉及压缩特性  

Thaw settlement and compression properties of silty clay under freeze-thaw circle of double direction freezing-one direction thawing

作　　者：阴琪翔[1] 周国庆[1,2] 赵晓东[1] 路贵林 赖泽金[2] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [2]中国矿业大学力学与建筑工程学院,江苏徐州221116

出　　处：《中国矿业大学学报》2015年第3期437-443,共7页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2012CB026103);国家自然科学基金项目(41271096);中国博士后科学基金项目(2014T70555)

摘　　要：自行设计了冻土冻融循环装置,基于此开展不同上边界冻结温度条件下粉质黏土的冻融循环试验.试验结果表明:1)随冻融次数增加,经高温冻结冻融作用和经低温冻结冻融作用当干密度ρd≤1.42g/cm3时,试样以压密变形为主,而低温冻结冻融作用后ρd>1.42g/cm3的试样则以膨胀变形为主;第2次冻融作用与第1次冻融作用相比,高温冻结冻融作用后的试样融沉系数α0大幅度降低,而低温冻结冻融作用后的试样α0则表现为增加;随冻融次数增加,α0趋于稳定值α07,且α07随上边界冻结温度的增加而增加.2)当上边界冻结温度高于-2.8℃时(包含-2.8℃),不同干密度土样冻融1次后压缩系数mv均降低,当上边界冻结温度低于-2.8℃时,ρd≥1.42g/cm3的试样1次冻融后的mv增大,ρd<1.42g/cm3的试样mv则减小;随冻融次数增加,mv逐渐增大并逐渐趋于稳定值mv7,且mv7随上边界冻结温度的降低而增加.Freeze-thaw circle tests of silty clay were carried out, which is based on the upper boundary freezing temperature freeze-thaw circle experimental device. The results show that, with the increase of freeze-thaw cycle times, samples under warm freezing temperature freeze- thaw cycle present mainly compaction, the same as samples whose dry density ρd≤1. 42 g/cma under low freezing temperature freeze-thaw cycle. However, samples whose dry density ρd〉 1.42 g/cm^3 under low freezing temperature freeze-thaw cycle present mainly expansion. Com- pared with the first freeze-thaw cycle, thaw settlement coefficient a0 of samples after the second warm freezing temperature freeze-thaw cycle decreased greatly. However, a0 increased after low freezing temperature freeze-thaw cycle, and a0 tended to be a stable value ao7 with the in- crease of freeze-thaw cycle times. Furthermore, a07 increased with the increase of upper bound- ary freezing temperature. When upper boundary freezing temperature higher than --2.8 ℃ （in-clude --2.8 ℃）, melted soil compression coefficient mv of different densities all decreased after one freeze-thaw cycle. However my of densities ρd≥1. 42 g/cma increased, and my of densities ρd〈1.42 g/cm^3 decreased after one freeze-thaw cycle, mv increased and tended to be a stable value rnv7 with the increase of freeze-thaw cycle times, and mv7 increased with the decrease of upper boundary freezing temperature.

关 键 词：冻融循环 双向冻结-单向融化 融沉系数 融土相对压缩系数 

分 类 号：TU445[建筑科学—岩土工程]