高应变率下深部煤岩介质损伤破裂机理及应用研究

The danger of coal and rock dynamic disaster such as rock-burst, coal and gas outburst is intensified by deep mining. The mechanical properties and fracture mechanism of coal and rock at high strain rates are the basis for studying the mechanism and control methods of deep coal rock dynamic disasters. With the help of Hopkinson pressure bar with the confining pressure, CT scanning system, rock dynamic damage theory, this paper carries out the systemic studies on the mechanical properties and fracture mechanism of coal and rock as follows: variation of macro deformation and failure characteristics of deep coal and rock with strain rates and stress state; the establishment of the relationship among microscopic characteristics of deformation and fracture of deep coal at high strain rates and its confining pressure effect, meso-fracture and macro-damage; experimental design of quantitative damage characteristics of coal and rock and 3D reconstruction of internal fracture distribution; the establishment of dynamic damage evolution equation, damage constitutive model and dynamic criterion of deep coal and rock by considering the effect of high ground stress ; stability characteristics, analysis method and control technology of surrounding rock under dynamic loading such as impact or blasting. The research results can further enrich the theory of rock dynamics, and provide a reliable theoretical basis for the analysis of dynamic stability of deep coal structure and process design as well.

煤矿深部开采加剧了冲击地压、煤与瓦斯突出等煤岩动力灾害发生的危险性。高应变率下煤岩力学特性及损伤破裂机理是研究深部煤岩动力灾害发生机理及控制方法的基础。本课题旨在借助带围压控制的Hopkinson杆试验系统、CT扫描系统、岩石动力损伤力学理论等，对深部煤岩力学特性及损伤破裂机理进行系统研究，包括：深部煤岩介质的宏观变形及破坏特征随应变率及地应力状态的变化规律；高应变率下深部煤岩的变形及损伤破裂的微细观特征及其围压效应，细观断裂与宏观破坏间联系的建立；煤岩介质定量损伤特性试验设计及内部裂隙分布特征的三维重构；考虑高地应力作用效应的深部煤岩动力损伤演化方程、损伤本构模型及煤岩动态强度准则建立；冲击或爆破等动力载荷作用下深部煤岩巷道围岩的稳定性特征、分析方法及控制技术。研究成果可进一步丰富岩石的动力学理论，同时为深部煤岩结构动力稳定性分析及工艺设计提供可靠的理论依据。

我国煤炭已全面进入深部开采阶段，深部煤岩赋存环境具有显著的“三高”特性, 加剧了冲击地压、煤与瓦斯突出等煤岩动力灾害发生的危险性,高应变率下煤岩力学特性及损伤破裂机理是研究深部煤岩动力灾害发生机理及控制方法的基础。本项目围绕深部开采过程中高应变率下煤岩介质力学问题，从深部煤岩介质高应变率荷载加载试验系统搭建与力学测试、高应变率下深部煤岩介质细观损伤破裂特征、高应变率下深部煤岩介质损伤演化机理、动载扰动下深部巷道围岩稳定性控制等四个方面开展了具体的研究工作。项目开展过程中，搭建了完善的分离式霍普金森压杆试验系统，开展了复杂环境（实时高温、实时低温、高围压）件下煤岩介质动态力学特性试验，揭示了深部煤岩介质动态宏观力学特性及破坏机制；对试样破坏过程进行了高速摄像观测，结合试样断面扫描电镜试验，获取了高应变率下深部煤岩介质细观损伤特征，揭示了深部煤岩介质动态细观断裂机制；构建了高应变率下深部煤岩介质损伤演化本构模型及动态破坏准则，提出了基于有限差分的模型二次开发方法，搭建了理论模型与实际问题分析的数值计算桥梁；建立了动力扰动下深部巷道围岩稳定性控制模型，阐明了巷道围岩的动态力学响应特征，建立了深部高地力与冲击动力载荷耦合作用下巷道围岩稳定性控制体系。研究成果可为深部煤炭资源安全开采中巷道围岩支护结构设计等提供科学指导。