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为探讨近距离煤层群工作面采场围岩失稳机制和开发相应的控制技术,采用理论计算、数值模拟和实验室试验综合方法,研究煤层群开采围岩采动应力场分布。阐明松散煤体注水加固的力学机制,并开发现场厚坚硬顶板深孔预裂爆破、深浅孔联合注水、新型采煤工艺综合技术措施。研究结果表明:在煤层群开采条件下,上下工作面相互影响程度剧烈,将下伏煤层工作面布置在上覆煤层开采后的卸压区内,可避免上煤层遗留煤柱高集中应力的影响,降低下伏煤层工作面原始应力水平。用设计的深孔预裂爆破工艺,能避免关键层断裂后对下伏煤层作面的动压冲击。提出的工作面低压短时间浅孔注水和2巷超前长孔预注水工艺,能提高松散煤体抗剪强度,增加煤体稳定性。
In order to discuss the instability mechanism of surrounding rock and the corresponding control technology in the mining face of the coal seam group with near distance, theoretical calculation, numerical simulation and laboratory test are used to study the stress field distribution of surrounding rock mining. The mechanics mechanism of water injection and reinforcement of loose coal body is elucidated and the comprehensive technical measures of deep well pre-cracking blasting, deep and shallow hole water injection and new coal mining technology are developed. The results show that under the mining conditions of coal seam group, the upper and lower working faces have a great influence on each other, and the coal seam face is arranged in the pressure relief zone after overlying coal seam mining to avoid the influence of high concentrated stress of coal pillar , Reduce the initial stress level of the underlying coal seam face. With the design of deep-hole pre-cracking blasting process, to avoid the key layer fracture on the underlying coal face for dynamic pressure impact. The proposed low-pressure short-time shallow hole water injection and 2 advanced long hole pre-injection process can increase the loose coal shear strength and increase the stability of coal.