深部煤柱非线性劣化特性与突变失稳诱冲机理研究

The coal pillar will be damaged under high stress and repeated disturbance in deep mining. And the further deterioration of the coal pillar with initial damage can cuase its abrupt instability during mining process and then induces the rock-burst disaste. In this project, the coal pillar is taken as the research object, and the innovative works are carried out as follows: (1) By triaxial cyclic loading and unloading test, the nonlinear cumulative characteristics and mechanism of coal deterioration damage were explained under the action of high stress-long time cyclic loading-unloading confining pressure, the failure mode and mechanism of coal under different influence factors were studied; (2) Based on the data of mechanical test and acoustic emission, CT scanning and characteristics of fragment distribution, the relationship between the failure behavior of coal rock and energy dissipation, release and its dynamic response characteristics were analyzed, the model of nonlinear dynamic instability was established, the mechanical and energy triggering conditions of rock-burst induced by the instability of coal pillar were proposed and the mechanism of catastrophe instability induced was revealed; (3) Based on field monitoring data and numerical simulation results, an index system was proposed for coal pillar instability induced rock-burst And the method of dividing the dangerous area of the coal pillar was put forward. The research results enrich the mechanism of catastrophe instability of coal pillar in deep mining and have important scientific significance and application prospect for improving prediction accuracy and prevention efficiency of rock burst.

深部煤柱在高应力、反复扰动下必然产生损伤，具有初始损伤的煤柱在采动过程中进一步劣化引发突变失稳导致冲击地压灾害的发生。本项目以损伤煤柱为研究对象，开展以下方面的创新性工作：（1）通过三轴循环载荷卸围压试验，阐释高应力-长时循环载荷-卸围压作用下煤体劣化损伤非线性累积特性和机制，揭示不同影响因素下煤岩破坏形式和机理；（2）基于力学试验数据、声发射监测、CT扫描和碎块分布特征，分析煤岩宏细观破坏行为与能量耗散、释放的关系及其动力响应特征，建立考虑煤体劣化损伤的非线性动力失稳模型，提出煤柱突变失稳诱发冲击地压的力学和能量触发条件，揭示煤柱突变失稳诱冲机理；（3）基于煤体变形、应力和能量实测数据与对应的数值计算结果，建立煤柱失稳冲击灾变的评价指标体系，提出深部煤柱冲击危险区域的划分方法。本项目研究成果对完善深部煤柱突变失稳诱冲机理，提高冲击地压预测精度和防治效率具有重要的科学意义和应用前景。

深部煤炭资源开采过程中，留设了大量不规则的承载煤柱，该类煤柱在高应力、反复扰动下发生变形、破坏，随时间增长产生明显的损伤，具有初始损伤的煤柱在采动过程中进一步劣化引发突变失稳导致冲击地压灾害的发生。本课题创新性的将煤岩体的初始损伤考虑在内，通过三轴循环载荷卸围压试验，阐释了高应力-长时循环载荷-卸围压作用下煤体劣化损伤非线性累积特性和机制，揭示了不同影响因素下煤岩破坏形式和机理；基于力学试验数据、声发射监测、CT扫描和碎块分布特征，分析了煤岩宏细观破坏行为与能量耗散、释放的关系及其动力响应特征，建立了考虑煤体劣化损伤的非线性动力失稳模型，提出了煤柱突变失稳诱发冲击地压的力学和能量触发条件，揭示了煤柱突变失稳诱冲机理；基于煤体变形、应力和能量现场实测数据与对应的数值计算结果，建立了煤柱失稳冲击灾变的评价指标体系，提出了深部煤柱冲击危险区域的划分方法，并根据煤体应力、变形、能量聚释的动态关联机制研究成果，结合现场实际应用，提出了等效面积下钻孔联合卸压创新方法，研制了前进式全自动可控变径卸压钻头，解决了受深部采场动力灾害影响下安全开采等问题。本课题研究成果完善了深部煤柱突变失稳诱冲机理，提高了冲击地压预测精度和防治效率，具有重要的科学意义和应用前景。