Three Gorges Research Center for Geo-Hazards of Ministry of Education, China University of Geosciences (Wuhan), Wuhan 430074, China.
China Communications Construction Company Second Highway Consultants Co., Ltd., Wuhan 430056, China.
Sensors (Basel). 2021 Sep 17;21(18):6251. doi: 10.3390/s21186251.
Seasonally frozen soil where uneven freeze-thaw damage is a major cause of highway deterioration has attracted increased attention in China with the rapid development of infrastructure projects. Based on Darcy's law of unsaturated soil seepage and heat conduction, the thermal-hydraulic-mechanical (THM) coupling model is established considering a variety of effects (i.e., ice-water phase transition, convective heat transfer, and ice blocking effect), and then the numerical solution of thermal-hydraulic fields of subgrade can be obtained. Then, a new concept, namely degree of freeze-thaw damage, is proposed by using the standard deviation of the ice content of subgrade during the annual freeze-thaw cycle. To analyze the freeze-thaw characteristics of highway subgrade, the model is applied in the monitored section of the Golmud to Nagqu portion of China National Highway G109. The results show that: (1) The hydrothermal field of subgrade has an obvious sunny-shady slopes effect, and its transverse distribution is not symmetrical; (2) the freeze-thaw damage area of subgrade obviously decreased under the insulation board measure; (3) under the combined anti-frost measures, the maximum frost heave amount of subgrade is significantly reduced. This study will provide references for the design of highway subgrades in seasonally frozen soil areas.
季节性冻土地区不均匀冻融破坏是导致公路恶化的主要原因，随着基础设施项目的快速发展，该地区受到了越来越多的关注。基于非饱和土渗流和热传导的达西定律，建立了考虑多种效应（即冰-水相变、对流传热和冰塞效应）的热-水-力（THM）耦合模型，然后可以得到路基热-水场的数值解。然后，通过使用路基在每年冻融循环过程中冰含量的标准偏差，提出了一个新的概念，即冻融损伤程度。为了分析公路路基的冻融特性，该模型应用于中国国道 G109 格尔木至那曲段的监测断面。结果表明：（1）路基水热场具有明显的阴阳坡效应，其横向分布不对称；（2）隔热板措施下路基的冻融损伤面积明显减小；（3）在综合抗冻措施下，路基的最大冻胀量显著降低。本研究将为季节性冻土地区公路路基的设计提供参考。
