填料类型对季节冻土区覆盖效应的影响  

Influence of subgrade filling types on covering effect in seasonally frozen soil area

作　　者：冯德刚 郝东苗 张明礼[2,3] 严艳锋 周志雄 张瑞玲 李广[2] FENG Degang;HAO Dongmiao;ZHANG Mingli;YAN Yanfeng;ZHOU Zhixiong;ZHANG Ruiling;LI Guang(Bridge and Tunnel Engineering Co.Ltd.,CCCC Third Highway Engineering Co.Ltd.,Beijing 100012,P.R.China;School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,Gansu Province,P.R.China;Geological Hazards Prevention Institute,Gansu Academy of Sciences,Lanzhou 730021,Gansu Province,P.R.China)

机构地区：[1]中交第三公路工程局桥梁隧道工程有限公司,北京100012 [2]兰州理工大学土木工程学院,兰州730050 [3]甘肃省科学院地质自然灾害防治研究所,兰州730021

出　　处：《深圳大学学报（理工版）》2022年第1期59-66,共8页Journal of Shenzhen University(Science and Engineering)

基　　金：国家自然科学基金资助项目(41961010,41861012);甘肃省基础研究基金资助项目(20JR5RA478);中交第三公路工程局有限公司技术服务项目(QSGS-YLTJ-4-JS-01-2019)。

摘　　要：季节冻土区高速公路路面的大面积覆盖层使得路基填料内部水分在外界温度梯度和路面隔水作用下向上迁移并累积,加剧了路基的冻胀和融沉危害.通过室内试验,重现了季节冻土地区路基覆盖效应形成过程,建立非饱和土的"水-汽-热"模型,仿真分析中国兰州某地区不同路基填料覆盖效应形成过程和差异.结果表明,季节温度作用下土体水分向不透水层底部聚集,且聚集现象随着冻融循环次数的增加而加剧;当路基填料分别为砂土、粉土和粉质黏土时,由于填料导热性能和持水性能的差异,最大冻结深度分别为1.21、0.97和0.89 m;不同覆盖层下的水分运移均以水汽为主,以粉土作为填料时的水汽迁移现象最明显,砂土、粉质黏土和粉土填料路基对应的水分迁移量分别为0.68%、2.86%和12.56%,三者水分聚集深度依次变浅.可见在已有的粉土路基工程中应重点防治水汽迁移引起的路基病害.The existence of a large area of expressway pavement in seasonally frozen soil region causes the moisture in roadbed filler to migrate upward and accumulate under the action of external temperature gradient and road barrier which aggravates the frost heave and thaw settlement of the subgrade. The formation process of subgrade covering effect in seasonally frozen soil area is reproduced by laboratory experiment. The water-vapor-heat model of unsaturated soil is established to simulate the formation process and difference of different subgrade filling cover effect in a certain area of Lanzhou. The results show that under the effect of seasonal temperature changes,soil water accumulates to the bottom of the impervious layer,and the accumulation phenomenon intensifies with freezingthawing cycles. When the subgrade fillings are sandy soil,silty soil and silty clay,the maximum frozen depths are1.21,0.97 and 0.89 m,respectively,due to the difference in thermal conductivity and soil moisture diffusivity of the fillings. Water vapor migration dominates the water transport in shallow ground,which is most significant in silty soil. Water accumulations of sandy soil,silty clay and silty soil subgrade are 0.68%,2.86% and 12.56%,respectively. The accumulation depth becomes shallower in turn. It is important to prevent and control the subgrade hazards caused by water vapor migration in the existing subgrade engineering.

关 键 词：岩土工程 冻土工程 覆盖效应 路基填料 数值模拟 水汽迁移 季节冻土 多场耦合 

分 类 号：U419[交通运输工程—道路与铁道工程]