宽幅沥青路面热效应对其下部土体热状态的影响

Study of the influence of large-width asphalt-concrete pavement on the thermal characteristics of underlying permafrost

在多年冻土区,道路工程建设会引起下伏冻土吸热融化,进而威胁上部工程稳定性,这一冻土问题是多年冻土区工程建设面对的重要问题.对于青藏高速公路而言,由于铺设高吸热性的沥青路面和路基幅面增宽引起的尺度效应,路基吸热量较普通路基将大幅增加,使得其冻土问题更为突出.基于此,利用数值仿真手段,考虑全球气候变暖背景,对宽幅路基修建完成后20 a的热状况进行预测研究和比较分析,阐明了宽幅面沥青路面热效应对下部土体热状态的影响及其与路基边坡水平热效应的综合贡献,比较分析了全幅修建和分幅修建条件下下伏冻土热状态的异同.研究成果将为多年冻土区高速公路的路基稳定性研究和建设模式等提供基础理论指导.

In permafrost regions, the construction of highway would cause thawing of underlying permafrost, which threatens the stability of engineering. This frozen soil problem is important for the engineering construction in permafrost regions. For the Qinghai-Tibet Expressway, due to the asphalt-concrete pavement with high heat absorption and scale effect caused by large embankment width, the heat absorption of embankment will increase greatly, resulting in permafrost problem more severe. In this paper, through numerical simulation, taking into account of global warming, the thermal characteristics of large-width embankment after 20 years of completion of works are predicted and analyzed. The influence of large-width asphalt-concrete pavement on the thermal charac- teristics of underlying permafrost is investigated. Additionally, the underlying permafrost thermal characteristics are compared between large-width embankment and separated double line embankment. The study result would supply fundamental theory guide for the stability study and construction model of expressway in permafrost regions.