典型近直立煤层群冲击地压机理及监测预警研究
Study on mechanism of rock burst and early warning of typical steeply inclined coal seams
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摘要: 近直立煤层群由于特殊的煤岩赋存和开采方式，覆岩破断运动及其导致的围岩静载应力分布和动载扰动特征与缓倾斜煤层有较大差异，已有冲击地压灾害在近直立煤层群开采矿井（SICS）发生。为指导类似赋存矿井冲击地压防治，以乌东矿南采区典型近直立煤层群为工程背景，从诱冲机理、监测预警及防治技术方面展开了系统研究，揭示了近直立煤层群压撬型冲击地压机理，建立了适用于近直立煤层的预警指标体系，提出了近直立煤层降载减撬冲击地压防治技术。结果表明：近直立煤层群综放开采下冲击地压显现具有巷道顶底板侧不对称和岩体压撬显现特征；煤体所受顶板和岩柱的压撬作用是诱发冲击的基础静载力源，悬顶和层间岩柱破裂产生的动载扰动对冲击显现有重要诱发作用，近直立煤层群综放开采冲击地压是顶板和岩柱压撬效应耦合作用结果；各预警指标对冲击地压和大能量矿震均具有一定的响应，各维度和各系统预警指标综合预警可综合各自优势实现互补，提高预警准确性；深浅孔交替爆破可削弱对煤体的压载荷和撬动效应，现场实施后，微震日总能量和频次明显减少，顶板和岩柱每米能量104 J以上微震事件较实施前平均减少了96%，卸压效果明显，冲击危险性降低。Abstract: Due to the special coal and rock occurrence and mining method,the breaking motion of overburden rock and the resulting surrounding rock static stress distribution and dynamic disturbance characteristics are quite different from those of gently inclined coal seams. The rock burst disaster has occurred in steeply inclined coal seams(SICS). To guide the prevention and control of rock burst in similar existing mines,taking the typical SICS in the south mining area of Wudong Mine as the engineering background,a systematic study has been carried out from the mechanism,early warning and prevention technology of rock burst. The coupled mechanism of compression and prying-induced rock burst in SICS is revealed. The early warning index system suitable for SICS is established,and the prevention and control technology of rock burst in SICS is put forward. The results show that the damage of rock burst under fully-mechanized top-coal caving mining of SICS has the characteristics of asymmetry on both sides of the roof and floor roadway,and compression and prying damage characteristics. The compressive and pried stress acted on the coal body is the basic static load that induces the rock burst. The rupture of the suspended roof and rock pillar have important inducing effects on the rock burst. The rock burst in SICS under fully-mechanized top-coal caving and filling mining is induced by coupling of compressive and prying action. Each index has obvious response characteristics to rock burst risk and high energy tremor. The comprehensive early warning of each dimension and each system early warning index can integrate their respective advantages to achieve complementarity and improve the accuracy of early warning. The alternate deep and shallow hole blasting can weaken the pressure load and the prying effect on the coal body,the daily total energy and event count of microseism are obviously reduced after on-site implementation. The average number of microseismic events occurred on roof and rock pillar above 104 J per meter is reduced by 96% compared with that before implementation,the pressure relief effect is obvious,and the rock burst risk is reduced.
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