摘要
以长春季节性冻土区粉质黏土为研究对象,利用单向冻结试验仪,通过改变试验装置顶部控温顶板温度,模拟土体实际所处温度环境,从试样表观冷生构造、内部结晶状态、试样竖向位移及内部含水率变化方面,进行冻胀机理分析。结果显示:试样内部纵剖面出现明显的连续冰结晶体,横剖面出现不规则状冰晶体,土体发生分凝冻胀;试样表观冷生构造为网状,且表面存在一定连续性的竖向裂缝;试样竖向位移随温度降低逐渐增大,-5~-15℃温度变化范围内,变化趋势最明显,-15~-25℃试样竖向冻胀位移继续增加,增加趋势减缓。试验结束后,试样内部含水率发生明显变化,顶部位置含水率变化由水分迁移引起,下方含水率变化由毛细作用力和渗透吸力造成。
Take seasonal permafrost area powdery clay in Changchun as the research object,and use one-way freezing tester to simulate the temperature environment of the soil body by changing the temperature of the temperature-control roof at the top of the tester to analyze the mechanism of freezing and expansion from the apparent cold structure of the specimen,the state of internal crystallization,the vertical displacement of the specimen and the change of the internal water content.The freezing and expansion mechanism was analyzed from the apparent cold growth structure of the specimen,internal crystallization state,vertical displacement of the specimen and change of internal water content.The result shows that the specimen appeared obvious continuous ice crystals in the internal longitudinal section,and irregular ice crystals appeared in the transverse section,and the soil body underwent sub-consolidation and freezing.The apparent cold structure of the specimen is in the form of network,and there are vertical cracks with certain continuity on the surface.The vertical displacement of the specimen gradually increased with the decrease of temperature,and the trend of change was most obvious in the range of temperature change from−5 to−15℃,and the vertical freezing and expansion displacement of the specimen continued to increase from−15 to−25℃,and the trend of increase slowed down.At the end of the test,the water content inside the specimen changed significantly,the water content change at the top position was caused by water migration,and the water content change at the bottom was caused by capillary force and osmotic suction.
作者
王骏华
宋韬
郭浩天
江瑶瑶
陈政辛
WANG Junhua;SONG Tao;GUO Haotian;JIANG Yaoyao;CHEN Zhengxin(School of Geomatics and Prospecting Engineering,Jilin Jianzhu University,Changchun 130118,China;Institute of Geotechnical Engineering of the Seasonal Frozen Region,Jilin Jianzhu University,Changchun 130118,China)
出处
《路基工程》
2024年第2期89-94,共6页
Subgrade Engineering
基金
吉林省科技发展计划项目(YDZJ202201ZYTS490)
吉林建筑大学省级创新训练项目(S202310191074)。
关键词
单向冻结
分凝冻胀
温度
水分迁移
冷生结构
unidirectional freezing
segregation frost heave
temperature
moisture migration
cold-born structures
