我国多年冻土区高速公路修筑关键问题研究

Key issues of highway construction in permafrost regions in China

面对我国多年冻土区高速公路建设规划和需求,文章从路基传热过程、主要影响因素,以及工程措施降温效能等方面对多年冻土区高速公路建设所面临问题进行了分析.研究发现:与青藏铁路和青藏普通公路相比,多年冻土区高速公路修筑后,路基吸热强度将成倍提高、更多的热量将向路基中心部位聚集且难以扩散,导致冻土退化速率和范围的增加.现有保护冻土的典型工程措施在高速公路条件下的应用均存在降温效能不足、整体和均匀降温困难,以及易导致纵向裂缝、不均匀沉降等工程病害问题,而通过采用分离式修筑或通过有针对性的新型工程措施的有效研发是解决这些问题的关键途径.

In the demand of highway construction in permafrost regions in our country, some key issues have been analyzed in this paper, such as the heat transfer process in embankment, the major influential factors as well as the cooling efficiency of engineering measures during the construction of highway in permafrost regions in China. It is found that the heating intensity of the embankment will be doubled, and more heat will be gathered in the center of subgrade which is hard to spread, resulting in the speeding of the permafrost degradation and the increase of the degraded permafrost in the condition of highway in permafrost regions compared with railway and ordinary way in Qinghai-Tibet Plateau. The existing typical engineering measures of protecting permafrost will suffer from problems such as insufficient cooling efficiency, hard to fulfill the need of overall and uniform cooling, longitudinal cracks, and uneven settlement in the condition of highway. It is found that the key way to solve these problems is the adoption of separate building or the research of new effective engineering measures.