常温脱湿与冻融路径下压实土的土水特征  

Soil-water characteristics of compacted soils during drying at room temperature and in freezing-thawing

作　　者：王协群[1] 周琪 韩仲 邹维列[2] 丁鲁强 WANG Xiequn;ZHOU Qi;HAN Zhong;ZOU Weilie;DING Luqiang(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070 [2]武汉大学土木建筑工程学院,湖北武汉430072

出　　处：《中南大学学报（自然科学版）》2021年第10期3559-3570,共12页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51809199,51979206,52078400)。

摘　　要：为比较常温脱湿与冻融路径下压实土的土水特征,分别采用压力板仪、盐溶液湿度平衡法和5TM温度-湿度传感器,测定压实黑龙江膨胀土和山东粉质黏土在常温脱湿路径下的土水特征曲线和冻结-融化路径下的冻结特征曲线。研究结果表明:1)在相同试验工况下,同种土在脱湿路径下的土水特征曲线与在冻结路径下的冻结特征曲线形状相似,但不重合;2)与粉质黏土相比,膨胀土在常温下的持水能力更强,在相同负温下未冻水含量更高,且冻结特征曲线在冻结和融化过程中的滞回现象更明显;3)干密度越大,土体在常温下的持水能力越强,在负温下的未冻水含量越低,在冻结过程中形成冰的初始温度越低,且土体冻结特征曲线的滞回现象越不明显;4)经3次冻融循环,土体的冻结特征曲线逐渐达到稳定;经10次冻融循环后,由于土体产生膨胀和微裂缝,土体中的未冻水含量有所下降。The SWCC(soil-water characteristics curve) during drying and SFCC(soil-freezing characteristic curve)were measured and compared during freezing and thawing for a silt in Shandong and an expansive soil in Heilongjiang by a pressure plate apparatus, vapor equilibrium method and 5 TM temperature-humidity sensors.The results show that for the same soil under the same testing condition, freezing branch of SFCC and drying SWCC are similar, but not identical. Compared with silt, expansive soil has higher water holding capacity at room temperature and higher unfrozen water content during freezing-thawing. SFCCs of expansive soil also demonstrate higher degree of hysteresis characteristics. Specimens with higher dry density retain more water at room temperature and in less unfrozen water during freezing-thawings, showing SFCCs with less hysteretic characteristics. In addition, the initial temperature of ice formation during freezing is also lower for specimens with higher dry density. SFCC reaches a stable state after 3 freeze-thaw cycles and unfrozen water content decreases after 10 freeze-thaw cycles due to the swelling of soil and the generation of micro-cracks.

关 键 词：非饱和土 冻土 土水特征曲线 干密度 温度 冻融循环 

分 类 号：TU443[建筑科学—岩土工程]