柔性基层沥青路面在动荷载作用下Top-Down开裂模拟研究

发布时间：2018-03-24 05:45

本文选题：道路工程　切入点：Top-Down开裂　出处：《公路交通科技》2017年09期

【摘要】：针对柔性基层沥青路面主要病害形式Top-Down开裂开展病害机理研究,为病害预防提供技术支持,有助于提高道路服务水平,延长路面使用寿命。首先,对国内外目前柔性基层沥青路面Top-Down开裂研究成果进行了对比研究,分析了不同研究成果中对于Top-Down开裂形式、裂缝形成与发展机理提出的一致以及尚未达成共识的结论,确定以动态荷载下路面结构厚度、车辆荷载作为主要分析对象。然后,利用有限元计算软件进行实体建模,参考国内已建成道路选定代表路面结构,确定各项路面参数,基于子午线轮胎按照三向应力建模;分析动荷载作用下的应力最不利位置以及应力分布;选取车辆荷载作为主要变量,对动荷载作用下柔性基层沥青路面Top-Down裂缝起裂和发展的影响因素进行研究。基于断裂力学,以轴载和路面结构层厚度为主要变量,对微裂缝出现后影响裂缝发展的不同因素进行了对比。结果显示:当路面处于完整、连续的工作状态时,在动荷载作用下,剪应力τ是TopDown裂缝形成的主要原因;当路表出现微裂缝后,轴载对于裂缝发展的影响要远大于路面处于完整、连续状态时轴载的影响,应力强度因子K_Ⅰ和K_Ⅱ的峰值显著提高,建议在柔性基层路面设计、验算时加入剪应力验算指标。
[Abstract]:This paper studies the mechanism of Top-Down cracking, which is the main disease form of asphalt pavement with flexible base, and provides technical support for disease prevention, which is helpful to improve the service level of road and prolong the service life of pavement. First of all, This paper makes a comparative study on Top-Down cracking of flexible base asphalt pavement at home and abroad, and analyzes the consensus of different research results on the form of Top-Down cracking, crack formation and development mechanism, and the conclusion that has not been reached. The thickness of pavement structure under dynamic load and vehicle load are determined as the main analysis objects. Then, the entity modeling is carried out by using finite element calculation software, and the pavement parameters are determined by referring to the representative pavement structure selected by the built roads in China. Based on the radial tire modeling according to the three-dimensional stress, the most unfavorable position of the stress under the dynamic load and the stress distribution are analyzed. The vehicle load is selected as the main variable. The factors affecting the initiation and development of Top-Down cracks in flexible asphalt pavement under dynamic loading are studied. Based on fracture mechanics, axial load and pavement structure thickness are taken as the main variables. The results show that when the pavement is in a complete and continuous working state, shear stress 蟿 is the main reason for the formation of TopDown cracks under dynamic load. The influence of axial load on crack development is much greater than that on pavement when there are micro-cracks on the pavement surface. The peak values of stress intensity factors K _ I and K _ II are significantly increased when the pavement is in a continuous state. It is suggested that the design of flexible base pavement should be carried out. Add shear stress check index when checking calculation.
【作者单位】：长安大学公路学院;中国交建西北区域总部;乌鲁木齐市建设委员会;
【分类号】：U416.217;U418.6

【相似文献】