Abstract:With the continuous increase of highway construction mileage in China at the present stage, compared with conventional plain areas, the various adverse effects brought by permafrost subgrade should be overcome in the process of highway construction in the high-cold permafrost regions. This article focuses on the in-depth study of the impact of thermal disturbance on the block stone subgrade in the frozen soil area. In the process of analyzing the state of the high-grade road subgrade in the region, the data of temperature status, heat absorption and release status and status of freeze-thaw cycle of the block stone subgrade are collected. The general law of the change of its thermal state is discussed. The results of the study show that the block stone subgrade in the frozen-soil area exhibits a good thermal stability and active cooling effect. The block stone subgrade can avoid the thermal disturbance to the subgrade temperature by speeding up the the air circulation between the temperature difference of the air, so as to reduce all kinds of subgrade diseases caused by the thermal disturbance. The maximum depth of thawing permafrost directly under the block rock subgrade is gradually increasing. There is an imbalance of heat absorption and discharge between the shady and sunny surfaces of the block stone subgrade. The absorption and release of heat at the shoulder on the sunny side was 2.7 times that of the shoulder on the shady side, and the absorption and release of heat at the foot on the sunny side was 2.3 times that of the foot on the shady side. With the unbalanced development of heat absorption and release on the shady and sunny surface of the stone subgrade, the corresponding rate of warming of the permafrost of the shady surface is lower than that of the permafrost of the sunny surface, and the upper limit of the development degree of heat absorption and release of the permafrost on the shady surface is also lower than that of the permafrost of the sunny surface.
