倾斜软煤层综放工作面初次“见方”回风巷矿压显现研究

Study on manifestation of ground pressure in"first square"return airway of inclined soft coal seam working face

孟家窑煤业于11501工作面开展倾斜软煤层赋存条件下留设15 m区段煤柱试验,自工作面初次“见方”后,该工作面回风巷超前工作面一定范围内变形异常,且时常伴有异响。针对这一问题,以11501工作面初次“见方”期间工况为研究背景,采用3DEC数值模拟软件建立11501工作面回采数值模型,分析了11501回风巷在工作面初次“见方”前后的矿压显现规律,从矿压角度解释了工作面初次“见方”期间回风巷内异响来源。结果表明,11501工作面超前支承压力影响范围为50~70 m,在来压期间回风巷下帮、顶部、上帮变形速率明显加快,并且出现非均匀变形;工作面“见方”期间,受采动影响采空区已破断直接顶再次破裂是回风巷异响的主要原因,受其影响11501回风巷出现下帮顶角下沉、下帮外鼓变形、托盘内陷于煤体、钢带崩断等现象。针对该问题,提出了11501回风巷非均化补强支护措施,并取得较好的应用效果。研究成果为11501工作面后续回采工作中维护回风巷提供了科学依据,可为相似倾斜软煤层赋存条件矿井提供借鉴。

A 15 m section coal pillar test was conducted under the conditions of inclined soft coal seams at the No.11501 working face in the Mengjiayao Coal Mine.After the"first square"of the working face,abnormal deformation occurred within a certain range ahead of the working face in the return airway,often accompanied by unusual sounds.Addressing this issue,the working conditions during the"first square"period of the No.11501 working face was taken as the research background.Using the 3DEC numerical simulation software,a numerical model of the No.11501 working face was established to analyze the evident patterns of ground pressure before and after the"first square"at the No.11501 return airway,explaining the sources of the unusual sounds within the return airway during the"first square"period.The results showed that the influence range of the advanced support pressure at the No.11501 working face was about 50-70 m.During the weighting period,the deformation rate of the lower,roof,and upper sides of the return airway accelerated significantly,and non-uniform deformation occured.During the"square"period in the working face,the main cause of the unusual sounds in the return airway was that the goaf has been broken and the roof has been broken again due to the impact of mining.This caused phenomena such as the sinking of the lower roof side,bulging deformation of the lower side,inwards collapse of the tray into the coal,and breakage of steel bands in the No.11501 return airway.To address this issue,non-uniform reinforcement support measures were proposed for the No.11501 return airway,achieving good application results.The research findings provide a scientific basis for maintaining the return airway in the subsequent mining work of the No.11501 working face and offer a reference for similar mines under inclined soft coal seam conditions.