西部多雨地区长大纵坡沥青路面耐久性及行车安全性研究

发布时间：2019-04-24 13:11

【摘要】：在我国西部地区山脉丘陵分布范围较广,地形地貌多样化,地质条件又复杂,所以在路线设计中不可避免的遇到长大纵坡的问题。西部某些地方降雨量大和长大纵坡这种特殊纵坡条件,造成车辆在长大纵坡地段行驶时不断地加减速与频繁的制动,从而给纵坡路段施加了很大的水平力,加之层间粘结不良、车辆超载、低速行驶和多雨等众多因素的综合影响,导致长大纵坡路段的车辙、推移和水损坏比普通沥青路面要严重多,因此,开展对长大纵坡沥青路面的研究具有重要意义。本文主要做了以下几方面的研究：(1)本文运用ANSYS有限元软件,选取一种常见的沥青路面结构,建立了基于粘弹性理论的三维有限元模型,阐述了长大纵坡路面破坏的两种主要形式：车辙和推移；并分析了其产生的原因。然后深入研究层间接触、超载、纵坡坡度、车辆低速、水平力等因素作用下长大纵坡路段路面的受力状态,并分析了不同因素作用下车辙深度和最大剪应力的变化特征,得出了各个影响因素与车辙深度和最大剪应力的定量关系。(2)利用动量定理和纵坡坡度不同受力状况,建立了水膜厚度较小(3mm)上坡和下坡以及水膜厚度较大(≥3mm)上坡和下坡四种情况下动水压力的力学计算模型,分析不同水膜厚度情况下动水压力与水膜厚度、车速、车辆荷载和纵坡坡度之间的关系。(3)长大纵坡沥青路面早期损害中还有一种更为严重的损坏就是水损害,路面渗入水、沥青路面结构层和交通荷载的动力耦合(水力耦合)作用是导致路面水损坏的主要原因之一。因此基于Biot固结理论和多雨地区长大纵坡的特点,建立了在移动荷载作用下饱和沥青路面“面层—基层—路基”二维三层体系水力耦合模型和水力耦合控制方程,在面层底部为完全排水条件下全面系统的分析了车辆荷载、行车速度、路面渗透系数和纵坡坡度对面层中正应力、孔隙水压力、剪应力和面层位移等物理量分布的影响,为长大纵坡沥青路面结构设计提供理论基础和参考。
[Abstract]:In western China, mountains and hills are widely distributed, topography and geomorphology are diversified, and geological conditions are complex, so it is inevitable to meet the problem of long longitudinal slope in route design. In some parts of the west, such special longitudinal slope conditions as heavy rainfall and long longitudinal slope result in constant acceleration and deceleration and frequent braking of vehicles in the long longitudinal slope section, thus exerting a great horizontal force on the longitudinal slope section and poor interlaminar bond. Many factors such as vehicle overload, low speed driving and heavy rain lead to more serious rut and water damage than ordinary asphalt pavement. Therefore, it is of great significance to carry out the research on long longitudinal slope asphalt pavement. The main contents of this paper are as follows: (1) in this paper, a three-dimensional finite element model based on viscoelastic theory is established by using ANSYS finite element software, choosing a common asphalt pavement structure, and establishing a three-dimensional finite element model based on viscoelastic theory. This paper expounds two main forms of pavement failure on long longitudinal slope: rut and passage; And the causes of its emergence are analyzed. Then, the stress state of long longitudinal slope road under the action of inter-layer contact, overload, longitudinal slope, low speed of vehicle, horizontal force and other factors is deeply studied, and the variation characteristics of rut depth and maximum shear stress under different factors are analyzed, and the characteristics of the change of rut depth and maximum shear stress under different factors are analyzed. The quantitative relationship between the influencing factors and rut depth and maximum shear stress is obtained. (2) using momentum theorem and different stress conditions of longitudinal slope, the relationship between each influence factor and rut depth and maximum shear stress is obtained. The mechanical calculation models of dynamic water pressure under the conditions of small thickness of water film (3mm) up and down slope and larger thickness of water film (3 mm) were established. The dynamic water pressure, water film thickness and speed of water film under different water film thickness were analyzed, and the dynamic water pressure and water film thickness under different water film thickness were analyzed, and the dynamic water pressure and water film thickness under different water film thickness were analyzed. The relationship between vehicle load and longitudinal slope. (3) there is a more serious damage in the early damage of asphalt pavement with long longitudinal slope, that is, water damage, and the road surface seeps into water. The dynamic coupling (hydraulic coupling) of asphalt pavement structure layer and traffic load is one of the main causes of pavement water damage. Therefore, based on the Biot consolidation theory and the characteristics of long longitudinal slope in rainy area, the hydraulic coupling model and hydraulic coupling control equation of saturated asphalt pavement "surface-base-roadbed" two-dimensional and three-layer system under moving load are established. The influences of vehicle load, driving speed, road permeability coefficient and longitudinal slope on the distribution of normal stress, pore water pressure, shear stress and surface displacement are analyzed systematically under the condition of complete drainage at the bottom of the surface layer. It provides a theoretical basis and reference for the structural design of long longitudinal slope asphalt pavement.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.217

【共引文献】