To explore the impact of lateral stress concentration in interlayer rock stratum on the exploitation of protected coal seam, a field experiment was carried out in a multi-seam mining structure. Lateral stress redistri...To explore the impact of lateral stress concentration in interlayer rock stratum on the exploitation of protected coal seam, a field experiment was carried out in a multi-seam mining structure. Lateral stress redistribution and interlayer rock failure behavior were surveyed. Then an assistant numerical investigation was implemented to evolve the effect of liberated seam mining and its influence on stress reconstruction in surrounding rock mass. The cause of lateral stress concentration and its impact were discussed finally. Key findings turn out that a certain lateral stress increases in interlayer rock stratum and concentrates on its lower region. Lateral stress concentration and interlayer rock failure are interactional. The former is an inducing factor of the latter;the latter promotes the increase of concentration degree. Extent of lateral stress concentration increases to the maximum as seam distance is about 50 m. But the efficacy of liberated seam mining decreases as the seam spacing gets larger. Protected seam mining is then classified based upon the impact of lateral stress concentration, which helps to prevent the rock burst hazard and then to achieve a reliable mining in deep mines.展开更多
在陕北榆林小纪汗煤矿实际建井开采过程中发现了煤层为矿井主充水含水层这种特殊的水文地质现象，为对这种特殊现象下底板岩层的力学性质进行分析，对现场底板岩样进行岩石矿物成分测试、岩石膨胀性测试及水作用下岩石强度弱化规律测试...在陕北榆林小纪汗煤矿实际建井开采过程中发现了煤层为矿井主充水含水层这种特殊的水文地质现象，为对这种特殊现象下底板岩层的力学性质进行分析，对现场底板岩样进行岩石矿物成分测试、岩石膨胀性测试及水作用下岩石强度弱化规律测试等一系列试验研究。研究发现：1）小纪汗煤矿煤层为裂隙含水层，且为矿井主充水含水层，底板岩层长时间受水侵蚀，岩体易于软化、变形，易造成岩层裂隙扩展及其稳定性破坏；2）底板岩样中含蒙脱石、伊利石等膨胀性矿物是底板岩层膨胀变形的微观影响因素；3）底板岩样浸水膨胀变形经过急速膨胀—变形缓慢—变形结束3个阶段，岩样浸水2 h 内的膨胀变形已占总变形量73.3%，浸水2～12 h，变形量占总变形量的24.7%，浸水12 h 后，试样基本不变形；4）岩样与水作用后其单轴抗压强度、弹性模量、劈裂抗拉强度随饱水时间的延长、含水率的增大而不断降低，总体呈指数关系递减；5）岩样浸水12 h后，岩石单轴抗压强度、弹性模量及抗拉强度降低值占总衰减值分别为71.6%，72.3%和65.4%，煤层裂隙水对底板岩层的侵蚀软化作用明显。展开更多
文摘To explore the impact of lateral stress concentration in interlayer rock stratum on the exploitation of protected coal seam, a field experiment was carried out in a multi-seam mining structure. Lateral stress redistribution and interlayer rock failure behavior were surveyed. Then an assistant numerical investigation was implemented to evolve the effect of liberated seam mining and its influence on stress reconstruction in surrounding rock mass. The cause of lateral stress concentration and its impact were discussed finally. Key findings turn out that a certain lateral stress increases in interlayer rock stratum and concentrates on its lower region. Lateral stress concentration and interlayer rock failure are interactional. The former is an inducing factor of the latter;the latter promotes the increase of concentration degree. Extent of lateral stress concentration increases to the maximum as seam distance is about 50 m. But the efficacy of liberated seam mining decreases as the seam spacing gets larger. Protected seam mining is then classified based upon the impact of lateral stress concentration, which helps to prevent the rock burst hazard and then to achieve a reliable mining in deep mines.
文摘在陕北榆林小纪汗煤矿实际建井开采过程中发现了煤层为矿井主充水含水层这种特殊的水文地质现象，为对这种特殊现象下底板岩层的力学性质进行分析，对现场底板岩样进行岩石矿物成分测试、岩石膨胀性测试及水作用下岩石强度弱化规律测试等一系列试验研究。研究发现：1）小纪汗煤矿煤层为裂隙含水层，且为矿井主充水含水层，底板岩层长时间受水侵蚀，岩体易于软化、变形，易造成岩层裂隙扩展及其稳定性破坏；2）底板岩样中含蒙脱石、伊利石等膨胀性矿物是底板岩层膨胀变形的微观影响因素；3）底板岩样浸水膨胀变形经过急速膨胀—变形缓慢—变形结束3个阶段，岩样浸水2 h 内的膨胀变形已占总变形量73.3%，浸水2～12 h，变形量占总变形量的24.7%，浸水12 h 后，试样基本不变形；4）岩样与水作用后其单轴抗压强度、弹性模量、劈裂抗拉强度随饱水时间的延长、含水率的增大而不断降低，总体呈指数关系递减；5）岩样浸水12 h后，岩石单轴抗压强度、弹性模量及抗拉强度降低值占总衰减值分别为71.6%，72.3%和65.4%，煤层裂隙水对底板岩层的侵蚀软化作用明显。
