断续节理岩体应力波传播规律与节理动态力学响应研究

Wave propagation characteristics and dynamic responses of rock joints are two core issues in dynamic behaviors of the non-persistent jointed rock masses. So far, only damage and fracture behaviors of the non-persistent jointed rock have been studied, wave propagation characteristics are still poorly understood, leading to the difficulty in explanation of the findings from physical mechanism views. This project aims to study the dynamic mechanical behaviors of the non-persistent jointed rocks. Firstly, transient evolution model of joint stiffness will be established to investigate the joint stiffness characteristics under different strain rates and damage evolution conditions. Secondly, the transmission and reflection coefficients along the rock joints will be experimental investigated. And then, distributions of the stress and strain inside rock masses would be achieved. The findings will be utilized to analyze the physical mechanisms of the variation of the contact state and fracture behaviors of rock joints. Finally, mechanical model of the non-persistent jointed rock masses will be proposed and corresponding numerical method on simulating the deformation, damage evolution and contact state of the non-persistent joints will be carried out. The findings in this project would be helpful in rock engineering, protect engineering and earthquake engineering.

断续节理岩体的动态力学特性涉及应力波在岩体中的传播规律和节理的动态力学响应。目前只是局部性的研究了动态荷载作用下断续节理岩体的损伤演化与破裂模式，而对应力波传播规律研究极少，导致无法从机理上解释断续节理的动态力学响应。本课题拟从波传播角度出发，揭示断续节理岩体内应力波传播规律，探索断续节理动态力学响应的物理力学机制。首先，建立节理刚度瞬态演化模型，探讨不同应变率与损伤演化条件下节理刚度的变化特征。其次，分析应力波在断续节理处的透反射系数，明确断续节理空间分布对岩体应力、应变场分布与变化规律的影响，继而探索节理面接触状态变化规律以及节理处裂纹扩展特征。最后，建立断续节理应力波传播理论模型，提出一种考虑动态荷载作用下节理变形、损伤演化、接触状态变化的数值计算方法。上述研究对岩体工程、防护工程、地震工程等具有较高的基础研究意义与工程应用价值。

断续节理岩体的动态力学特性涉及应力波在岩体中的传播规律和节理的动态力学响应。本项目针对断续节理岩体动态力学行为开展了深入研究。在数值模拟方面，本项目研发了一种可以考虑损伤演化的接触单元模型，该方法能够考虑节理、断层等非连续岩体结构在外荷载作用下的损伤演化过程，还可以充分考虑不连续面之间接触，滑移和分离接触状态变化，并成功地应用于应力波在断续节理岩体中传播规律的研究，揭示了不同断续节理空间分布对应力波传播与衰减规律的影响机制。同时，本项目充分考虑了岩体撞击过程中的不同岩体界面的接触碰撞过程，揭示了不同撞击条件下岩体的破坏特征。在试验方面，基于霍普金森杆试验系统，首先系统开展了多次拉伸波作用下岩石拉伸破坏特性研究，提出了描述反复多次拉伸波扰动下岩石杆内部损伤演化定量分析方法。随后，分析了强应力波扰动作用下，不同断续节理倾角、岩桥长度、交错角与节理间距对断续节理岩体动力学响应规律与破坏特征的影响，揭示了断续节理岩体的动力学破坏机制。本项目研究成果对含节理裂隙等复杂岩体结构在施工与运营期动力响应稳定性的研究具有重要的科学意义与工程价值。