福建高速公路沥青路面排水体系数值分析

Numerical Analysis of Asphalt Pavement Drainage System in Fujian Expressways

福建省多雨潮湿,降雨对高速公路沥青路面性能和行车安全影响非常大.福建省在研究和长期实践基础上形成了非常有特色的沥青路面排水体系,为了检验其有效性,进行了高速公路沥青路面排水体系的数值分析.基于Biot动态固结理论的Lagrange有限差分方法,建立了路域3D模型.考虑降雨、表面径流、路面结构内部及地下水流动等因素,进行了超高缓和段路表集水状况、路面结构内部层底集水深度和孔隙动水压力、路面边部排水和中央分隔带排水设施排水能力进行模拟分析.分析时考虑了动态移动荷载、动水场作用下的多孔路面结构的动态流固耦合,但计算时不考虑蒸发作用.结果表明:(1)采用移动路脊法设计后,超高缓和段的路表雨天集水次数可减少85.7%;(2)组合式基层沥青路面结构自由水完全排出时间为0~5d;与半刚性基层沥青路面结构相比较,组合式基层沥青路面结构中沥青层底无自由水天数可增加180%,同时沥青层层底孔隙动水压力相应可降低73.5%;(3)福建高速公路排水设施排水能力均有一定富裕,路基顶面横向排水管、碎石透水层、级配碎石层底横向排水管、集水井和缝隙式纵向排水沟的排水最小富裕度分别为96.7%,95.1%,73.5%,41.3%和26.9%;(4)根据数值分析结果,可以对排水设施尺寸或设置间距等进一步完善.

It is wet and rainy in Fujian Province, which has a great influence on the performance and driving safety of expressway asphalt pavement. Based on the research and long-term practice, a special asphalt pavement drainage system has been formed in Fujian Province. In order to test its effectiveness, a numerical analysis on the drainage system of expressway asphalt pavement is carried out. Based on the Biot dynamic consolidation theory and the Lagrange finite difference method, a 3D model of the pavement is established. Considering the factors such as rainfall, surface runoff, sub-structure and groundwater flows, the simulations of the road surface catchment condition of ultra-high alleviation section, the water catchment depth at bottom of pavement structure, the pore dynamic water pressure, the drainage of pavement edge, and the drainage capacity of central separation zone drainage facilities are carried out. Dynamic fluid-solid coupling of porous pavement under dynamic moving load and dynamic water field is considered in the analysis, but evaporation is not considered in the calculation. The result shows that (1) The times of road surface catchment in rainy days can be reduced by 85. 7 % after the application of movable road ridge method.(2) The complete discharge time of free water in the combined base asphalt pavement is about 0 - 5 d. The days for free of water at the bottom of asphalt layer of the structure can increase by 1 80%, and its pore dynamic water pressure can decrease by 73. 5 % compared with the semi-rigid asphalt pavement structure.( 3 ) The drainage capacity of the drainage facilities in Fujian expressways is relatively rich, the minimum richness of lateral drainage pipe at the top of roadbed, gravel permeable layer, lateral drainage pipe at the bottom of graded gravel layer, catchment well and longitudinal drain is 96. 7 %, 95 . 1 %, 7 3 . 5 %, 4 1 . 3 % and 2 6 . 9 % respectively.(4) According to the numerical analysis result, the dimension or spacing of the drainage facilities can be further optimized.