中文摘要：

采用离散元方法构建了沥青混合料马歇尔数字试件，模拟了间接拉伸试验，研究了粘结强度比、颗粒摩擦因数和加载速率对微裂缝扩展过程的影响，分析了试件内部颗粒的细观响应。模拟结果表明：粘结强度比越大，沥青的粘结特性越明显，使得微裂缝的类型由法向渐变为切向，当粘结强度比由0．500增大到4．000时，接触力减小了78．05％，位移减小了78．57％；摩擦因数的增大，提高了集料的粗糙度，当摩擦因数由0．3增大到0．7时，接触力增大了31．21％，位移减小了21．45％，但其对微裂缝的分布影响不大，主要为法向微裂缝；当加载速率由0．03mm·s^-1增大到0．07mm·s^-1时，接触力增大了3．50％，微裂缝的类型、数量与位移大小基本不变，相比沥青和集料，加载条件对微裂缝扩展的影响很小。

英文摘要：

： Marshall numerical specimens of asphalt mixture were made by using discrete element method, indirect tensile test was conducted, the influences of parallel-bond strength ratios, particle friction coefficients and loading velocities on micro-crack extension processes were studied, and the mesomechanics responses of particles in the specimens were analyzed. Simulated result indicates that the bonding characteristics of asphalt are more obvious when the parallelbond strength ratio is larger, which makes the types of micro cracks change from normal microcracks to tangential micro cracks. When the ratio changes from 0. 500 to 4. 000, the contact force reduces by 78.05%, and the displacement reduces by 78.57%. The roughness of aggregate increases with the increase of friction coefficient. When the coefficient changes from 0.3 to 0.7, the contact force increases by 31.21%, and the displacement reduces by 21.45%, but there is little effect on the distribution of micro-cracks that are mainly normal micro-cracks. When the loading velocity changes from 0.03 mm · s ^-1 to 0.07 mm · s^- 1, the contact force increases by3. 5%, and the types and numbers of micro-cracks and the amounts of displacements do not change basically. Loading conditions have less effect on micro-crack extension compared with asphalt and aggregate. 1 tab, 14 figs, 11 refs.