摘要
为研究柔性基层沥青路面纵向裂缝的产生机理和发展规律,实测了子午线货车轮胎在不同轴重和胎压下的接地印迹与应力。借助实测的子午线轮胎接地面积和简化的非均布轮载应力,建立了轮胎-路面非均布条形荷载力学计算模型,对不同沥青层厚度的柔性基层沥青路面结构进行了三维有限元分析,计算超载和设计轴载工况下2种路面结构最大拉应力和最大剪应力值及其发生位置,并依托级配碎石基层沥青路面足尺试验路进行了加速加载破坏试验,得到了中低温环境下沥青层开裂类型、发生位置和发展变化规律,提出以轮胎胎纹间隙处的最大剪应力作为沥青路面自顶向下开裂的力学指标;基于力学分析指标和足尺试验路疲劳破坏作用次数,构建沥青路面自顶向下疲劳开裂预估模型。研究结果表明:柔性基层沥青路面最大拉应力远离轮迹带,其应力值远小于沥青混合料的容许拉应力,对沥青层自顶向下扩展的纵向开裂无影响;最大剪应力发生在路表或距路表一定深度范围内,轴载越大,最大剪应力越接近路表,水平力越大,最大剪应力越靠近轮底中心;当轮载水平力系数由0增加至0.5时,最大剪应力由轮底边缘移至子午线轮胎第2条凸纹与第3条凸纹间隙处。足尺试验路重轴载加速加载破坏试验时,柔性基层沥青路面最先发生了位于轮底中心、源自路表自顶向下扩展的间断纵向裂缝,随重复轮载作用纵向裂缝逐渐连通,裂缝的扩展方向与轮胎胎纹走向一致,印证了纵向开裂源于轮底轮胎胎纹间隙处的理论分析结果,明晰了柔性基层沥青路面自顶向下开裂的关键破坏源。
To study the mechanism of longitudinal cracks in asphalt pavement with a flexible base course and the law of crack development, the grounding impression and stress of truck tires under different axle loads and tire pressures were measured.With the help of the measured tire grounding area and simplified non-uniform distributed contact stress from the radial tires, a mechanical calculation model of tire-pavement under a non-uniform distributed strip load was established. A 3D finite element analysis was developed for flexible base asphalt pavement structures with different asphalt layer thicknesses. Through the analysis, the maximum tensile stress and maximum shear stress and their acting positions on the two pavement structures were calculated under the overload conditions and the designed axle load conditions. An accelerated loading failure test was also conducted on a full-scale test road of graded crushed stone base asphalt pavement to obtain the type, location and development law of asphalt layer cracks in medium-and low-temperature environments. The maximum shear stress at the gap between the patterned ribs of the tire tread was proposed as the mechanical index of the top-down cracking of asphalt pavement. Then, based on the mechanical analysis and fatigue failure times of the test road, a top-down fatigue cracking prediction model of asphalt pavement was established. The results show that the maximum tensile stress of flexible base asphalt pavement is far away from the wheel track zone, and its value is far less than the allowable tensile stress of asphalt mixture, which has no effect on the top-down longitudinal cracks. The maximum horizontal shear stress occurs on the pavement surface or within a certain depth from the pavement surface, and the greater the axle load, the closer the maximum shear stress. In addition, the greater the horizontal force, the closer the maximum shear stress is to the center of the wheel bottom, and when the coefficient of horizontal force increases from 0 to 0.5, the maximum shear stress moves from the edge of the wheel bottom to the gap between the second and third patterned ribs of the radial tire. During the accelerated loading failure test with a heavy axle load on the full-scale test road, the flexible base asphalt pavement first has short top-down longitudinal cracks originating from the pavement surface. With the action of the wheel load, these short cracks are connected to each other and are located at the center of the bottom of the wheel. In addition, the direction of their propagation is consistent with that of the patterned ribs, which supports the theoretical analysis results, and indicating that longitudinal cracking originates from the gap between the patterned ribs of the bottom of the wheel. 8 tabs, 21 figs, 28 refs.
作者
叶亚丽
徐全亮
宁选杰
余四新
YE Ya-li;XU Quan-liang;NING Xuan-jie;YU Si-xin(School of Transportation and Civil Engineering, Shandong Jiaotong University, Jinan 250357, Shandong, China;RIOH Transport Consultants Ltd., Beijing 100191, China;Qilu Transportation Development Group, Co., Ltd., Jinan 250102, Shandong, China)
出处
《长安大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第2期35-46,共12页
Journal of Chang’an University(Natural Science Edition)
基金
山东省自然科学基金项目(ZR2015EL047)
山东省高等学校科技计划项目(J18KA209)
山东省交通运输科技计划项目(2017B12)
浙江省交通运输厅科研计划项目(2014H27)
关键词
道路工程
加速加载试验
非均布条形轮胎荷载
最大剪应力
胎纹
预估模型
裂缝发展
road engineering
accelerated loading failure test
non-uniform distributed strip tire load
maximum shear stress
tire tread pattern
prediction model
crack propagation
