重载交通沥青路面剪切屈服区分布规律研究

Research on Distributing Regularity of Shear Yielding Area in Asphalt Pavement under Heavy Axle Load

半刚性基层沥青路面的面层沥青混合料在重轴载车辆作用下,产生的剪应力超过其抗剪强度而容易产生过大的剪切塑性变形,使其产生横向剪切流动。考虑面层沥青混合料的粘弹性特性、不同轮载条件下非均布接地压力和路面面层及基层间的实际接触状态,选择4种典型沥青路面结构,用有限元分析方法进行力学响应分析,假定沥青混合料符合莫尔库仑屈服准则,编制基于COSMOS/M的二次开发程序找出重轴载条件下沥青面层剪切屈服区分布规律,解释重载交通沥青路面车辙产生机理。研究结果表明,沥青面层剪切屈服区随着车辆轴载增大而逐步扩展,不同路面结构沥青面层剪切屈服区扩展变化规律不尽相同,路面车辙发展速度和产生部位也不相同。

Under the heavy axle load, the great shearing plastic deformation from the surface asphalt mixture of the semi-rigid asphalt pavement structure comes easily into being when the shear stress of the asphalt concrete exceeds its shear strength, which results in the transverse flowing deformation. Taken the visco-elastic properties of the asphalt mixtures, the non-uniform tire contacting pressures under the different axle loads and the frictional condition between the pavement layers into consideration, the mechanical responses of four typical asphalt pavement structures were computed by means of nonlinear finite element method, and the shear yielding domain distribution in the asphalt layers was found out by the secondary developed program based on the finite element software COSMOS/M on the assumption that asphalt mixture obeys the Moore-coulomb yielding rule to explain the rutting mechanism of asphalt pavement under heavy traffic. The result shows that （1） the shear yielding domain of the asphalt layers extends gradually with the increase of axle load; （2） the extending regularity, growing rate and location of the shear yielding domain differs from each other according to the different pavement structure.