不同赋存深度煤岩采动渗流力学行为及损伤破坏能量机制研究

The seepage mechanical behavior and permeability evolution of coal under real mining-induced stress conditions are the major concerns in the coal mining and coalbed methane extraction. Obtaining the real mining-induced seepage mechanical characteristics and the energy mechanism of damage failure of coal at different depths is the prerequisite for massive, safe and efficient exploitation of the deep coal resources in the future. In this project, the real occurrence environments and mining-induced stress evolution processes of coal at different depths in Pingdingshan coal mine areas will be firstly investigated. Then, the in-situ coal samples at different depths will be taken as the research objects, and the macro and meso-scopical combination research method of theoretical modeling, experimental simulation and numerical analyses will be used comprehensively in this project. By breaking through the problem that the physical properties and the mining-induced stress environment evolutions of the coal mass at different depths are not fully considered in previous researches, a new method of the real mining-induced seepage mechanical characteristics of coal at different depths will be established. Then, the real mining-induced seepage mechanical behavior, the stress-fracture-seepage coupling mechanism and the dynamic permeability evolution mechanism of mining-induced coal at different depths will be explored. A coupling model that considering the comprehensive effects of depths will be established, and the energy mechanism of damage process of mining-induced coal at different depths will also be obtained in this project to serve the coal resource mining practice that marching to the deep constantly.

采动应力环境影响下的煤岩渗流力学行为和渗透能力演化特征始终是煤炭和煤层气资源开采实践中最为关注的基础问题，而探明不同赋存深度煤岩真实采动渗流力学特征及损伤破坏过程的能量机制则是未来面向深部大范围安全高效开采煤炭资源的基本前提。本项目拟以平顶山矿区不同赋存深度煤岩真实赋存环境和采动应力演化过程为切入点，以不同赋存深度原位煤样为研究对象，综合运用理论建模、实验模拟与数值分析结合的宏细观综合研究方法，突破以往研究中不能系统考虑不同赋存深度煤岩物性及工程扰动应力环境演化过程的瓶颈，建立不同赋存深度煤岩采动渗流力学特性模拟试验新方法，探明不同赋存深度煤岩真实采动渗流力学行为规律，揭示不同赋存深度采动煤岩应力-裂隙-渗流耦合作用机制及渗透能力动态演化机理，构建考虑赋存深度综合影响的煤岩采动渗流耦合模型，探究不同赋存深度采动煤岩损伤破坏过程的能量机制，服务不断走向深部的煤炭资源采掘实践。

采动应力环境影响下的煤岩力学行为和渗透能力特征始终是煤炭和煤层气资源开采实践中最为关注的基础问题，而随着浅部资源不断枯竭，开采深度逐渐增加，深部工程煤岩体的采动渗流力学特性与浅部工程大不相同，根本原因是煤岩体采动破坏力学行为和能量演化规律随赋存深度增加变化显著，亟需开展不同赋存深度采动煤岩真实采动渗流力学行为规律及损伤破坏能量机制基础科学研究。为此，课题组从河南平顶山300-1100m不同深度煤炭采掘实践出发，探明了不同深度、开采方式下煤炭采动过程中应力环境演化的共性规律，形成了考虑赋存深度影响的煤岩采动渗流力学行为实验方法，研究了不同赋存深度煤岩体采动力学行为。进一步结合CT扫描等技术，探索了不同赋存深度煤岩体的初始渗透特性，并定量描述了深部煤岩体经历采动过程后渗流通道展布的复杂程度。同时，以能量视角查明了不同深度煤岩损伤破坏过程特征和机制，构建了考虑赋存深度影响的峰前能量型脆性度指标。最终构建了考虑不同赋存深度和开采方式的煤岩应力-裂隙-渗流耦合模型，实现了对不同赋存深度煤岩体采动力学行为和渗流规律的较好描述。项目研究成果已初步应用于平煤八矿、十矿、十二矿煤炭资源开采，并有望进一步推广至其他深部煤炭矿井，助力提升我国深部煤炭开发和煤与瓦斯共采能力。