基于离散元方法的沥青路面温度应力计算方法及裂缝发育规律  

Calculation method of thermal stress and cracks development law of asphalt pavement based on discrete element method

作　　者：汤钧尧 马涛[1] 郑彬双 黄晓明[1] TANG Jun-yao;MA Tao;ZHENG Bin-shuang;HUANG Xiao-ming(School of Transportation,Southeast University,Nanjing 21l189,Jiangsu,China;Shanghai Municipal Engineering Design Institute(Group)Co.,Ltd,Shanghai 200092,China)

机构地区：[1]东南大学交通学院,江苏南京211189 [2]上海市政工程设计研究总院(集团)有限公司,上海200092

出　　处：《长安大学学报（自然科学版）》2022年第5期12-20,共9页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51778139)。

摘　　要：为合理表征沥青混合料的细观特性,并深入研究沥青混合料低温开裂过程中温度应力积累和裂缝扩展的细观机理,基于离散元程序PFC2D建立沥青混合料约束试件温度应力(TSRST)模拟试验方法。根据逆向体视学原理和概率论方法,引入沥青混合料三维体积级配与二维数量级配的转化关系,建立二维离散元虚拟试件;结合沥青混合料各组分之间的接触行为特点,赋予不同的接触本构模型,借助室内试验测定集料和沥青砂浆的宏观参数,推导得到不同温度下各相材料间的细观接触参数;通过TSRST模拟试验,分析试件内部温度场变化规律、温度应力曲线、细观接触力的分布特征以及低温开裂的细观机理。研究结果表明:TSRST离散元模拟和室内试验的结果具有较高的吻合度,断裂温度相对误差为3.7%,断裂强度相对误差为4.8%,TSRST模拟试验具有较高的准确性,能够作为试件低温抗裂性评价的可靠方法;试件的破坏可以分为3个阶段:(1)起裂阶段,在转化点温度前,试件内部个别接触点接触失效,对结构整体受力状况影响较小;(2)稳定扩展阶段,温度达到断裂温度前,随着温度的降低,接触力增加,裂缝沿试件薄弱部位发展,微裂缝数量缓慢稳定增长;(3)不稳定扩展阶段,温度达到断裂温度后,短时间内温度应力下降了66%,裂缝总量增加了132条,微裂缝已汇聚成可见的宏观裂缝,并沿着构造相对薄弱的位置快速扩展,导致试件失去整体承载力。To reasonably characterize the meso-characteristics of asphalt mixture, and furtherly investigate the meso mechanism of thermal stress accumulation and crack propagation in the process of low-temperature cracking of asphalt mixture, the virtual test method of asphalt mixture thermal stress restrained specimen test(TSRST) was established based on the discrete element program PFC2 D. According to the principle of reverse stereology and the method of probability theory, the transformation relationship between three-dimensional volume gradation and two-dimensional quantitative gradation of asphalt mixture was introduced, and the two-dimensional discrete element virtual specimen was established. Combined with the characteristics of contact behavior between components of asphalt mixture, different contact constitutive models were given. The macro parameters of aggregate and asphalt mortar were measured by laboratory test, and the meso contact parameters between materials at different temperatures were deduced. Through TSRST virtual test, the variation law of internal temperature field, temperature stress curve, distribution characteristics of meso contact force and meso-mechanism of low temperature cracking were analyzed. The results show that TSRST discrete element simulation are in good agreement with the indoor test results. The relative error of fracture temperature is 3.7%, and the relative error of fracture strength is 4.8%, which proves that the TSRST virtual test has high accuracy, and can be used as a reliable method for the evaluation of low-temperature crack resistance of specimens. The failure of the specimen can be divided into three stages,(1) crack initiation stage, before the transformation point temperature, the contact failure of individual contact points in the specimen has little impact on the overall stress state of the structure,(2) stable propagation stage, before the temperature reaches the fracture temperature, with the decrease of temperature and the increase of contact force, the cracks devel

关 键 词：道路工程 温度应力计算 离散元方法 温度应力模拟试验 低温开裂 

分 类 号：U416[交通运输工程—道路与铁道工程]