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为了研究大粒径透水性沥青混合料层(LSPM)对防治半刚性沥青路面反射裂缝的机理,应用离散元软件建立了包含LSPM层和半刚性基层的复合路面结构离散元模型,计算分析了裂缝尖端处的应力场以及LSPM层内细观结构对裂尖应力的作用,研究了在荷载作用下不同的级配、粗集料几何特征、空隙等混合料细观结构因素对沥青混合料反射裂缝的影响机理,以及沥青路面反射裂缝扩展速率的分析。结果表明:在车辆荷载作用下,半刚性基层中存在的裂缝会在LSPM层底产生明显的应力集中,其中正载作用在裂尖处产生水平应力集中,偏载会产生剪应力集中,应力以裂缝尖端处为中心向周围递减;LSPM层粗集料粒径偏大的沥青混合料在裂尖区域的应力场总体应力水平低于粒径较小的混合料,裂缝开展的速率相对较慢;LSPM能有效地降低裂尖处应力集中,延缓裂缝的开展。
In order to study the mechanism of large particle size water-permeable asphalt mixture (LSPM) for preventing and controlling reflective cracks in semi-rigid asphalt pavement, a discrete element model of composite pavement structure containing LSPM and semi-rigid base was established by using discrete element software. The stress field at the tip and the mesostructure in the LSPM layer on the crack tip stress were studied. The effects of different grading, coarse aggregate geometry, voids and other mesostructures on the crack reflection of asphalt mixture The influence mechanism and the analysis of asphalt pavement reflection crack propagation rate. The results show that under the vehicle load, the cracks in the semi-rigid base layer will produce obvious stress concentration in the LSPM layer, of which the positive loading produces horizontal stress concentration at the crack tip and the eccentric load will produce shear stress concentration. The stress The crack tip decreases gradually around the center; the overall stress level of stress field in the crack tip area is lower than that of the mixture with smaller particle size, and the crack propagation rate is relatively slow; LSPM can effectively reduce the stress concentration at the crack tip and delay the crack initiation.