School of Mines,China University of Mining & Technology
Huoluowan Colliery,Shendong Tianlong Group

针对末采期工作面采出上覆遗留煤柱,近距离回撤通道高低位厚硬顶板易发生联合失稳而导致巷道强变形、设备难以安全回撤等的难题;建立了遗留煤柱高、低位坚硬顶板结构“联合失稳”力学模型;分析了遗留煤柱下开采时支架载荷变化情况,阐述了末采期遗留煤柱下高低位顶板发生联合失稳的风险来源;基于遗留煤柱顶板支承压力峰值分布区域与水力压裂裂缝扩展规律,结合低位基本顶断裂位置对回撤通道矿压显现影响,综合提出了“高位定向孔区域水力压裂+低位直孔局部水力压裂”的围岩结构优化控制技术,并在霍洛湾矿31107工作面进行试验。现场应用表明,提出的围岩优化控制技术可有效控制末采期高应力集中强动载,实现了回撤通道围岩稳定、设备安全回撤的目标。

When the overlying residual coal pillar is extracted from the working face at the end of mining period,the high and low thick hard roof strata of the short-distance retreat roadway is prone to joint instability,which leads to the strong deformation of the roadway and the difficulty of safe withdrawal of equipment. A mechanical model of joint instability was establised in this study for the residual coal pillar with high and low hard roof strata. The load variation of bracket was analyzed when coal mining beneath the residual coal pillar. This study also elucidated the sources of the combined instability risk in the high and low roof strata beneath the residual coal pillar during the final extraction phase. The surrounding rock optimization and control technology of high-level directional hole area hydraulic fracturing + low-level straight hole local hydraulic fracturing was proposed based on the distribution of peak abutment pressure in the roof of the residual coal pillar,the law of hydraulic fracturing fracture expansion,and the effect offracture location of low basic roof on the stress evolution of retreat roadways. The proposed control technology was successfully used in the 31107 working face of Huoluowan Colliery. The proposed technology could effectively control the high stress concentration and strong dynamic load in the final mining period,and ensure the stability of the surrounding rock of retreat roadways and the safe withdrawal of equipment.

国家自然科学基金资助项目(52174132)