含夹矸煤层水力裂缝在煤岩界面的扩展规律  

Laws of Hydrofracture Expansion in Coal and Rock Interface in Coal Seam Containing Gangue

作　　者：石应东 康天合[1] 李立功 SHI Yingdong;ICANG Tianhe;LI Ligong(Institute of Mining Technology,Taiyuan University of Technology,Taiyuan 0300:24,China)

机构地区：[1]太原理工大学采煤工艺研究所,山西太原030024

出　　处：《煤矿安全》2018年第12期173-176,共4页Safety in Coal Mines

摘　　要：针对含夹矸煤层中裂缝在煤岩界面的扩展问题,应用线弹性断裂力学的理论和方法,分析了含夹矸煤层水力裂缝缝高在煤层与夹矸界面处的扩展路径及其判别准则,着重讨论缝高穿透煤岩界面的扩展距离与缝内水压的关系。研究表明:缝高在煤岩界面有3种扩展方式,即裂缝被限制在煤层中停止扩展、裂缝沿煤岩界面扩展及裂缝穿透界面扩展。当裂缝穿过煤层与夹矸之间的界面进入夹矸层,用叠加法计算应力强度因子,得到缝高穿透界面后在夹矸中扩展距离的计算方法。由工程实例可知,随水力裂缝缝内水压的升高,缝高穿透界面扩展距离急剧增大。In view of the problem of fractures expansion in coal and rock interface in coal seam containing gangue, based on the theory and method of linear elastic fracture mechanics, the expansion path and discriminant criterion of hydraulic fracture height of coal seam containing gangue at the interface between coal seam and dirt band are analyzed. The relationship between the expansion distance of the interface with high penetration and the water pressure inside the seam is discussed. There are three modes of seam height expansion in the coal-rock interface, including stopping extension in coal seams, extending along the interface and penetrating into interlayer. When the crack passes through the interface between coal seam and gangue and enters the dirt band, the stress intensity factor is calculated with the superposition method, and the calculation method of the expansion distance in gangue after the crack height passing through the interface is obtained. It can be seen from the engineering practice that the expansion distance of the penetration interface of the fracture height increases sharply with the increase of water pressure in the hydraulic fracture.

关 键 词：夹矸 厚煤层 水力压裂 缝高扩展 应力强度因子 煤层气井 

分 类 号：TD712[矿业工程—矿井通风与安全]