基于离散-连续耦合的落锤-路面动态相互作用研究

落锤冲击是一种典型的中低速碰撞，也是现今工程技术中的重要力学问题。在公路工程领域，一方面利用落锤产生的巨大瞬时冲击力达到压实、加固、微裂、破碎、检测等目的，另一方面是避免过大的冲击力对结构物产生破坏作用。为了探索落锤-路面动态相互作用规律，基于PFC5.0 Suite和FLAC3D构建了离散-连续耦合模型，模拟无损和有损状态下水泥路面板承受落锤冲击过程中加速度的变化规律。通过路面无损状态下的仿真结果分析发现：①落锤冲击加速度曲线拥有多个波峰和波谷，且均与路面和落锤参数具有相关性；②冲击加速度峰值与落锤高度和水泥板模量正相关，而与落锤质量负相关；③落锤高度对冲击持续时间影响不大，而落锤质量将显著增长冲击持续时间。通过路面有损状态下的仿真结果分析，发现：①冲击加速度曲线特征点与路面破损状态密切相关；②随着水泥面板破损程度增大，冲击加速度值整体减小，冲击持续时间延长；③落锤高度和质量对路面破损模式的影响差异较大，前者主要引起表面破损，而后者主要引起底部破损。研究认为：落锤冲击加速度特征值与路面破损程度和破损模式之间存在密切的关联，相关研究结果可用于路面破损检测、破碎或微裂状态评价等实际工程中，同时也可为工程器械的改进和研发提供基础支撑。

Coupled Discrete-continuous Simulation and Analysis of Dynamic Interactions Between Hammer and Pavement

As typical low-or medium-speed collisions, hammer impacts have become an important engineering mechanical problem. In highway engineering, impact forces from hammers are commonly used to achieve engineering goals of compaction, reinforcement, micro-cracking, crushing, and inspection; however, their detrimental effects should be avoided. A coupled discrete-continuous model based on PFC5.0 Suite and FLAC3D was developed to simulate the dynamic interactions between the hammer and pavement to explore the mechanism of their underlying dynamic interaction. The acceleration data of hammer were collected and analyzed by considering both the destructive and non-destructive cement pavement conditions. From the simulation results of the non-destructive pavement conditions, it is observed that:① in each impact acceleration curve, there are multiple peaks and troughs which are closely related to the pavement and hammer parameters; ② the peak acceleration values are positively correlated with both falling height and cement concrete modulus, whereas they are inversely correlated with the hammer mass; ③ the falling height of the hammer has negligible effects on the impact durations, whereas the hammer mass significantly increases the impact durations. From the simulation results of the destructive pavement conditions, it is observed that:① the pavement destructions are closely related to the feature points of the impact acceleration curves; ② with the increasing degree of pavement destruction, the corresponding acceleration decreases with greater impact duration; ③ the falling height could result in pavement surface damage, whereas the hammer mass mainly results in damage to the pavement bottom. It is believed that the hammer acceleration values and pavement destruction features are closely correlated. These correlations are applicable for pavement distress detection, pavement crushing, and pavement micro-cracking. Additionally, the results could establish a solid foundation for further machinery development.