级配碎石复合式基层沥青路面力学响应研究

级配碎石复合式基层沥青路面结构能够有效解决半刚性基层所存在的病害问题。为了了解落锤式弯沉仪(FWD)作用下沥青路面的动力响应特性,采用ABAQUS软件建立两种路面结构有限元模型,分析了复合式路面结构与半刚性基层路面的差异,并研究了不同路面结构参数条件下的各结构层特征及其影响相关性。结果表明:在相同路面结构条件下,通过数值模拟分析得到的路表弯沉数值与路面实测结果的趋势是一致的,具有很高的相关性;采用级配碎石基层替代部分水泥稳定碎石,在一定程度上削弱了路面结构的整体刚度和抗疲劳性能;对路面结构进行半正弦曲线加载,路表弯沉随时间的变化存在一定的滞后现象,结构层厚度和回弹模量对路表弯沉具有重要影响;结构参数对面层层底最大拉应变的影响程度大小为:水泥稳定碎石回弹模量>沥青面层厚度>水泥稳定碎石厚度>沥青面层模量。

Study on Mechanical Performance of Unbound Graded Aggregate Composite-based Asphalt Pavement

Unbound graded aggregate composite-based asphalt pavement is applied to effectively solve the cracks disease of the semi-rigid base pavement.In order to understand the dynamic response characteristics of the asphalt pavement under the falling weight deflector(FWD),finite element models of two kinds of pavement structures were built by the ABAQUS program.The mechanical difference between composite pavement structure and semi-rigid pavement was analyzed.In addition,the influence and correlation of different structural parameters on mechanical characteristics of pavement structures were also discussed.The results show that on the same pavement structure condition,the numerical simulation results are consistent with the measured results in terms of surface deflection;the overall stiffness and fatigue resistance of the pavement structure is weakened when the graded gravel base is used to replace a part of the cement stabilized gravel;the hysteresis occurs under semi-sinusoidal loading in the law of road surface deflection and the thickness and modulus of the structural layer have important influence on the deflection;The influence degree of the structural parameters on the maximum bottom tensile strain of asphalt layer is:cement stabilized gravel rebound modulus>asphalt surface thickness>cement stabilized gravel thickness>asphalt surface modulus.