School of Safety Science and Engineering, Anhui University of Science and Technology
Scientific and Technological Research Platform for Disaster Prevention and Control of Deep Coal Mining, Anhui University of Science and Technology

深部煤炭开采地质条件恶化，原生煤在多期构造运动作用下形成松软低渗高瓦斯构造煤层，煤层钻孔施工困难，爆破增透产生的裂隙不发育且易于重新压实。针对目前构造煤层顶板爆破致裂增透关键技术没有得到根本突破问题，构建试验模型进行煤层顶板爆破相似模拟试验和数值分析，监测跨界面应力波传播和宏观三维裂隙演化形态，再现了爆破应力波传播和煤岩体内部损伤破坏过程。研究表明：(1) 构造煤层爆破损伤范围主要集中在爆破孔和煤层上下煤岩交界面附近煤体；构造煤顶板爆破产生跨界面致裂卸压裂纹，爆破损伤沿爆破孔向四周岩体扩展，最后蔓延到煤层底板，爆破孔位置和上部煤岩交界面以及煤层内部的损伤较为严重。(2) 爆破应力波从构造煤层顶板传播到煤岩交界面时发生波的透射和反射，透射的压缩应力波破坏煤体；反射的拉伸应力波反作用于煤岩交界面区域岩体。(3) 爆破累积损伤产生的跨界面交叉裂纹卸压，使顶板岩层裂隙和构造煤层裂隙贯通，有利于构造煤层的瓦斯垂向运移流动和卸压瓦斯抽采。现场应用表明，煤层顶板爆破瓦斯抽采纯量及其浓度快速上升，瓦斯抽采纯量从爆破前的0.07 m3/min提高到1.73 m3/min，体积分数从10.46%上升到68.50%，并且长时间维持在较高水平。研究成果可为深部构造煤层瓦斯高效抽采提供理论基础和技术支持。

Deep coal mining is challenging due to deteriorating geological conditions. After undergoing multiphase tectonic movements, primary coals have evolved into soft tectonic coal seams with low permeability and high gas content, complicating drilling in coal seams. In this case, the blasting-induced fractures are not well-developed and are prone to be re-compacted. So far, no fundamental breakthrough has been achieved in the key technology of fracturing for permeability enhancement technology through the roof blasting of tectonic coal seams. Given this, this study established test models for similar simulation tests and numerical analysis on the roof blasting of coal seams. By monitoring the cross-interface stress wave propagation and the macroscopic three-dimensional fracture evolutionary morphologies, this study reproduced the blasting stress wave propagation, as well as the internal damage and failure processes of coals and rocks. Key findings are as follows: (1) The blasting-induced damage to tectonic coal seams is primarily distributed in blasting boreholes and coals near the upper and lower coal-rock interfaces. The roof blasting of tectonic coals produces cross-interface fractures for pressure relief, and the blasting-induced damage propagates along blasting boreholes to the surrounding rock masses, ultimately spreading to the footwall of coal seams. Serious damage is found in blasting boreholes, near the upper coal-rock interfaces, and inside coal seams. (2) The blasting stress waves undergo transmission and reflection when propagating to coal-rock interfaces from the roof of the tectonic coal seams. The transmitted compressive stress waves damage coals, while the reflected tensile stress waves react on the rock masses at coal-rock interfaces. (3) The pressure relief induced by cross-interface fractures, generated by blasting-induced cumulative damage, connect the rock fractures on the roof with the fractures within tectonic coal seams, facilitating the vertical migration of gas in tectonic coal seams and gas drainage with stress relief. The on-site application shows that gas drainage following the roof blasting of coal seams manifested rapidly increased pure gas flow and concentration, which increased from 0.07 to 1.73 m3/min and from 10.46% to 68.5% (volume fraction), respectively and maintained at high levels for a prolonged period. The results of this study can provide a theoretical basis and technical support for efficient gas drainage from deep tectonic coal seams.

国家自然科学基金项目(52374179)；安徽省自然科学基金项目(2208085ME125)；安徽省高校优秀青年人才支持计划项目(gxyq2022016)；煤矿深井开采灾害防治技术科技研发平台(安徽理工大学)开放基金项目(DPDCM2204)

高魁，王有为，乔国栋，等. 构造煤层顶板爆破跨界面致裂增透机制研究及应用[J]. 煤田地质与勘探，2024，52(4)：1−12.

GAO Kui，WANG Youwei，QIAO Guodong，et al. Mechanism and application of cross-interface fracturing for permeability enhancement through the roof blasting of tectonic coal seams[J]. Coal Geology & Exploration，2024，52(4)：1−12.