Experimental Study on Vapor Transfer under Pot-Cover Effect of Subgrade Soil in Cold Regions

被引：0

作者：

Luo T. ^{[1
]}

Chen H. ^{[1
]}

Yao Y. ^{[1
]}

Chen W. ^{[1
]}

机构：

[1] School of Transportation Science and Engineering, Beihang University, Beijing

来源：

Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/Journal of Tianjin University Science and Technology | 2019年 / 52卷

关键词：

Cold regions; Pot-cover effect; Subgrade soil; Vapor transfer; Water content;

D O I：

10.11784/tdxbz201902031

中图分类号：

学科分类号：

摘要：

Pot-cover effect refers to the phenomenon of moisture accumulation beneath a pavement under condensation or desublimation because the pavement obstructs vapor transfer in the soil. A series of tests were carried out with silty clay from Beijing Daxing International Airport using a self-developed pot-cover effect test equipment to study the vapor transfer law and analyze the pot-cover effect mechanism of the actual subgrade soil in cold regions. The influences of temperature differences, initial water content, and test period on the pot-cover effect were revealed. The test results are as follows: under temperature difference, vapor migrated to the low-temperature zone, which will cause the increase in topsoil moisture. With the increase in temperature difference, the water contents in the upper part of samples increased, and the water vapor migrated into the samples more easily. When the top temperature was positive, the peak value of water content only occurred under the cover. When the top temperature was negative, a second peak value occurred at the freezing front. When the initial water content was lower, gaseous water migration dominated in the samples. The liquid water migration dominated when the initial water content was higher, and the mixed water migration dominated when the initial water content was moderate. Vapor transfer can result in water vapor absorption from water source and increase the total soil moisture. A 30-day vapor transfer test was carried out under freezing condition. The result showed that water vapor continuously migrated into the soil samples. The water quantity of the upper part of the sample and the whole sample both increased during the test. After the test, an ice layer caused by vapor desublimation formed under the cover, and the soil nearly saturated there. The test results indicate that the pot-cover effect can cause significant increase in the actual subgrade soil moisture in cold regions and may lead to engineering diseases. © 2019, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.

引用

页码：29 / 34

页数：5

共 14 条

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