【目的】为分析煤柱下方综采工作面受集中应力影响的强矿压显现特征,以霍洛湾矿31106工作面过上覆集中煤柱为工程背景进行研究。【方法】通过工作面实测支架阻力精细化分析过煤柱期间的矿压特征和支架适应性,开展相似材料模拟实验,揭示工作面过煤柱的强动压机理,并提出过煤柱的水力压裂切顶控制技术。【结果】结果表明:工作面出煤柱期间,支架阻力整体由大到小依次为中部、下部、上部,工作面周期来压步距为10.85m,平均持续长度为4.27m,占周期来压时长的40%,平均动载系数达到1.4.出煤柱期间支架载荷超过正常工作阻力(35MPa)的比例分别为:32.14%、63.83%和87.94%,支架受顶板断裂的动载作用并承受长时间的高静载作用。相似材料模拟表明,出煤柱时上覆岩层形成的“T型结构”失稳发生整体的回转下沉,引起下部工作面老顶同步破断,造成工作面大范围支架阻力的增加,液压支架安全阀开启率达到31.2%,存在压架风险。【结论】据此提出了工作面过煤柱的水力压裂切顶技术,现场试验表明水力切顶后工作面在出煤柱后10m范围内并没有出现强矿压显现,降低了支架承受的动载荷和高静载,未发生强动载压架现象。

【Purposes】 In order to study the characteristics of strong mine pressure under the influence of concentrated stress in fully mechanized mining face under residual pillar, the 31106 working face of Huoluowan Mine passing through the overlying concentrated coal pillar is taken as the engineering background. 【Methods】 The mine pressure characteristics and support adaptability during passing through the coal pillar are analyzed through the measured support resistance of the working face. The similar material simulation experiment is carried out to reveal the strong dynamic pressure mechanism of the working face passing through the coal pillar, and the hydrau-lic fracturing roof cutting control technology passing through the coal pillar is proposed. 【Find-ings】 The results showed that during the period of coal pillar extraction in the working face, the overall support resistance is middle, lower, upper. The periodic weighting step distance of the working face is 10.85 m, the average continuous length is 4.27 m, accounting for 40% of the pe-riodic weighting time, and the average dynamic load coefficient reaches 1.4. The proportions of the support load exceeding the normal working resistance (35 MPa) during the coal pillar are 32.14%, 63.83%, and 87.94%. The working face is subjected to the dynamic load of roof frac-ture and long-term high static load. Similar material simulation shows that when the coal pillar is pulled out, the overlying ‘T-type structure’ is unstable and the overall rotary sinking occurs, causing the main roof of the lower working face to break synchronously, resulting in an increase in the support resistance of the working face in a large range. The opening rate of the safety valve of the hydraulic support reaches 31.2%, and there is a risk of support crushing. 【Conclusions】 On the basis of above findings, the hydraulic fracturing roof cutting technology for working face crossing coal pillar is put forward. Field test shows that the hydraulic fracturing roof cutting in the coal pillar area can effectively destroy the roof integrity. There is no strong mine pressure within 10 m after the working face is out of the coal pillar, which reduces the dynamic load and high static load of the support, and no strong dynamic load crushing occurs.