多孔沥青路面改善青藏高原公路路堤热稳定性机理研究

For the geological and geographical scenarios of frozen soil engineering on the Qinghai-Tibet Plateau, the primary focus of this study will be on porous asphalt pavement system as a cool pavement technology for improving the thermal stability of high-grade highway embankment in permafrost regions of the Qinghai-Tibet Plateau. During a wet-warm season, the moisture existing in the voids of the porous asphalt pavement system with a higher porosity can be evaporated, thus cooling the embankment due to evaporative heat loss. During a dry-cold season, the porous asphalt pavement system can produce the enhanced cooling ability of highway embankment due to direct formation a pore air circulation in conjunction with the ambient cold air. Therefore, during an annual cycle of harmonic air temperature these integrated capabilities can improve the thermal stability of the embankment and underlying foundation soils. Both experimental and theoretical researches on the evaporative effectiveness of cooling the highway embankment in the porous asphalt pavement structure are performed. The influence of key parameters such as thickness, porosity and water content in the porous asphalt pavement structure, rainfall and weather conditions on improving the thermal stability of highway embankment in permafrost regions is analyzed. The impacting mechanism of the porous asphalt pavement technologies for cooling down the highway embankment and improving the thermal stability of the embankment and underlying foundation soils in permafrost regions is explained. The theory and nonlinear numerical simulation methods are developed in order to calculate this heat and mass transfer problem coupled with conduction, convection, radiation, evaporation and seepage in the porous media-moisture-air system. Under the climate warming conditions, the long-term tendency of thermal stability into the porous asphalt pavement embankment and underlying foundation soils are evaluated by numerical simulation. And some recommendations for the design and applicability of the porous asphalt pavement technologies for ensuring the thermal stability of high-grad highway embankment in permafrost regions of the Qinghai-Tibet Plateau are provided.

针对青藏高原冻土区工程环境地质特点，采用冷路面技术的多孔沥青路面改善青藏高原冻土区高等级公路热稳定性。高孔隙率多孔沥青路面结构在暖季湿润条件下水分能通过孔隙发生蒸发散热降低路堤温度，而在冷季干燥条件下孔隙又能使外界冷空气与孔隙空气产生对流循环而增强路堤降温能力，综合全年气温循环能改善冻土区路堤及土层的热稳定性。开展多孔沥青路面结构蒸发散热效应对降低公路路堤温度影响的实验和理论研究，分析多孔沥青层厚度、孔隙率、含水量、雨水及气温条件等参数对冻土区路堤热稳定性的影响规律，明确多孔沥青路面结构降低路堤温度和改善冻土区公路路堤及其土层热稳定性的作用机理，研究水-气-多孔介质系统耦合传导、对流、辐射、蒸发及渗流等热质传输问题的理论和数值分析方法，预测全球气候变暖条件下冻土区多孔沥青路面公路路堤及其土层热稳定性的长期变化趋势，提出适合青藏高原冻土区高等级公路稳定性要求的多孔沥青路堤结构形式及应用原则。

针对青藏高原冻土区工程环境地质特点，采用冷路面技术的多孔沥青路面改善青藏高原冻土区高等级公路热稳定性。高孔隙率多孔沥青路面结构在暖季湿润条件下水分能通过孔隙发生蒸发散热降低路堤温度，而在冷季干燥条件下孔隙又能使外界冷空气与孔隙空气产生对流循环而增强路堤降温能力，综合全年气温循环能改善冻土区路堤及土层的热稳定性。开展多孔沥青路面结构蒸发散热效应对降低公路路堤温度影响的实验和理论研究，分析多孔沥青层厚度、孔隙率、含水量、雨水及气温条件等参数对冻土区路堤热稳定性的影响规律，明确多孔沥青路面结构降低路堤温度和改善冻土区公路路堤及其土层热稳定性的作用机理，研究水-气-多孔介质系统耦合传导、对流、辐射、蒸发及渗流等热质传输问题的理论和数值分析方法，预测全球气候变暖条件下冻土区多孔沥青路面公路路堤及其土层热稳定性的长期变化趋势，提出适合青藏高原冻土区高等级公路稳定性要求的多孔沥青路堤结构形式及应用原则，改进能增强青藏高原冻土区高等级公路热稳定性的技术措施。已发表学术论文4篇，其中，SCI收录论文2篇，授权发明专利1项、实用新型专利10项，公布发明专利12项，毕业硕士研究生11名，其中毕业5名。