摘要
保护层开采能够有效防治煤矿瓦斯问题,保护效果是保护层开采设计的重要依据。为了研究保护层开采时被保护层裂隙演化和渗透特征,采用现场测试对保护层开采前后裂隙发育特征进行分析,并对保护层开采过程中被保护层渗透率和卸压特征进行了相似模拟和数值模拟研究,研究结果表明:保护层开采前,裂隙发育数量和宽度较小,受保护层开采影响后,裂隙数量和宽度明显增加,裂隙发育度提高;保护层开采后被保护层可划分原岩应力区、支撑应力区、开采卸压区、应力恢复区4个区,支撑应力区渗透率降低,应力恢复区渗透率小幅提高,开采卸压区内渗透率可达到开采前的7倍以上;保护层开采后,被保护层卸压幅度将近50%,卸压率曲线呈“沟渠状”分布,被保护层膨胀率整体大于3‰,满足《防治煤与瓦斯突出细则》的要求,保护层开采可以达到卸压增透的效果。
Protective layer mining could effectively prevent coal mine gas problems.The protection effect was an important basis for the protection layer mining design.In order to study the crack evolution and permeability characteristics of the protected layer during protection mining,field tests were performed to analyze the development characteristics of the cracks before and after the protection layer mining,and similar permeability and pressure relief characteristics of the protected layer were simulated during the protection layer mining process.The numerical study shows that before the protective layer was mined,the number of cracks developed were small.After being affected by the protective layer mining,the number and extent of the cracks increase significantly,and the degree of crack development increases.After the protective layer was mined,the protected layer could be divided into four areas:rock stress area,supporting stress area,mining pressure relief area,and stress recovery area.The permeability of the supporting stress area was reduced,and the permeability of the stress recovery area was slightly increased.The permeability in the mining pressure relief area can reach more than 7 times before mining.After the protective layer was mined,the pressure relief of the protected layer was nearly 50%,and the pressure relief rate curve was distributed in a"ditch shape".After the protective layer was mined,the overall expansion rate of the protected layer was greater than 3‰,achieving the effect of pressure relief and permeability enhancement.
作者
王晶
王晓蕾
WANG Jing;WANG Xiaolei(Department of Mining Engineering,Lvliang University,Lvliang 033000,China)
出处
《采矿与岩层控制工程学报》
北大核心
2021年第3期58-66,共9页
Journal of Mining and Strata Control Engineering
基金
山西省高等学校科技创新资助项目(2019L0954)
吕梁市开发区高层次科技人才引进计划专项资助项目(2019110)。
关键词
保护层开采
裂隙演化
渗透特征
卸压
protective layer mining
fracture evolution
penetration characteristics
pressure relief
作者简介
王晶(1986-),女,山西吕梁人,助教,硕士,主要从事矿井地质等方面的研究工作。E-mail:471371562@qq.com。
