为探究水泥稳定碎石微裂细观演化机理，构建了细观非均质水泥稳定碎石数值模型，结合室内无侧限抗压强度试验和单轴压缩数值试验反演出模型细观参数，引入微裂隙网络研究不同裂隙参数对微裂程度的影响，分析不同裂隙数目下系统能量演化规律。结果表明：数值模拟与室内试验结果基本吻合，构建的水泥稳定碎石离散元模型可较为准确地表征材料细观破坏特征；微裂损伤是二次振动加载后裂隙宽度增大和裂隙数目增多共同作用的结果，裂隙密度对水泥稳定碎石微裂程度起决定性作用；裂隙密度增加，材料储存弹性应变能的能力减弱，峰值点水泥稳定碎石材料的输入总能量降低。验证了早期微裂对于降低收缩应力的积极作用，揭示了水泥稳定碎石材料微裂力学特征和细观机理。

To investigate the micro-cracking evolution mechanism of cement stabilized macadam, a numerical model of mesoscale heterogeneous cement stabilized macadam was established. The microfracture network was introduced into the fine-scale inhomogeneous model and the relevant parameters were obtained using unconfined compressive strength tests. Then, the effect of different microfracture parameters on the micro-cracking degree was explored according to the displacement variation of particles in the model under vibration load. Finally, the energy evolution law of the system with different microfracture numbers was further analyzed. The results indicate that the numerical simulation results are in good agreement with the laboratory test results, the discrete element model of cement stabilized macadam can accurately characterize the mesoscopic failure characteristics of materials. Micro-cracking damage after the secondary vibration load together with the increase of microfracture width and microfracture number as a result. The microfracture density plays a decisive role in the degree of microcrack for cement stabilized macadam. With the increase of the microfracture number, the elastic strain energy storage capacity of the material decreases, and the total energy input of the cement stabilized macadam decreases. This study has proved that the positive effect of early micro-cracking on shrinkage stress reduction. In addition, the mechanical characteristics and fine mechanism of micro-cracking in cement stabilized macadam materials are revealed.

TU521.2;U414

国家自然科学基金（51978236）；天津市交通运输科技发展项目（2022-01）