采矿与安全工程学报
採礦與安全工程學報
채광여안전공정학보
JOURNAL OF MINING AND SAFETY ENGINEERING
2013年
3期
449-455
,共7页
抽放钻孔%流变特性%应力分布%移动变形%塑性软化%扩容%软硬煤
抽放鑽孔%流變特性%應力分佈%移動變形%塑性軟化%擴容%軟硬煤
추방찬공%류변특성%응력분포%이동변형%소성연화%확용%연경매
gas drainage borehole%rheological property%stress distribution%movement law%plastic softening%dilatancy%soft and hard coal mass
为了研究抽放钻孔周围煤体的应力分布及移动变形规律，分析了钻孔周围煤体的力学特性，建立了考虑煤的塑性软化和扩容特性的黏弹塑性模型，得到了煤体应力、位移、孔径变化和卸压范围的表达式，对比分析了软硬煤层钻孔的应力分布及卸压效果，研究了抽放钻孔孔径变化规律，解释了软煤层钻孔抽放体积分数快速衰减的原因。研究结果表明：钻孔周围煤体具有塑性软化、扩容和流变特性，软煤层钻孔具有更好的卸压效果，蠕变变形更为剧烈，在短时间内就可能发生失稳破坏，阻塞瓦斯抽放的通道，致使瓦斯抽采体积分数迅速下降；硬煤层钻孔直径虽有缩小但仍处于稳定状态，并不发生堵孔现象，但是到井田深部由于应力增大，蠕变变形加剧，就有可能发生失稳破坏。研究成果与生产实践具有较好的一致性，可以为瓦斯抽采参数的确定提供理论指导。
為瞭研究抽放鑽孔週圍煤體的應力分佈及移動變形規律，分析瞭鑽孔週圍煤體的力學特性，建立瞭攷慮煤的塑性軟化和擴容特性的黏彈塑性模型，得到瞭煤體應力、位移、孔徑變化和卸壓範圍的錶達式，對比分析瞭軟硬煤層鑽孔的應力分佈及卸壓效果，研究瞭抽放鑽孔孔徑變化規律，解釋瞭軟煤層鑽孔抽放體積分數快速衰減的原因。研究結果錶明：鑽孔週圍煤體具有塑性軟化、擴容和流變特性，軟煤層鑽孔具有更好的卸壓效果，蠕變變形更為劇烈，在短時間內就可能髮生失穩破壞，阻塞瓦斯抽放的通道，緻使瓦斯抽採體積分數迅速下降；硬煤層鑽孔直徑雖有縮小但仍處于穩定狀態，併不髮生堵孔現象，但是到井田深部由于應力增大，蠕變變形加劇，就有可能髮生失穩破壞。研究成果與生產實踐具有較好的一緻性，可以為瓦斯抽採參數的確定提供理論指導。
위료연구추방찬공주위매체적응력분포급이동변형규률，분석료찬공주위매체적역학특성，건립료고필매적소성연화화확용특성적점탄소성모형，득도료매체응력、위이、공경변화화사압범위적표체식，대비분석료연경매층찬공적응력분포급사압효과，연구료추방찬공공경변화규률，해석료연매층찬공추방체적분수쾌속쇠감적원인。연구결과표명：찬공주위매체구유소성연화、확용화류변특성，연매층찬공구유경호적사압효과，연변변형경위극렬，재단시간내취가능발생실은파배，조새와사추방적통도，치사와사추채체적분수신속하강；경매층찬공직경수유축소단잉처우은정상태，병불발생도공현상，단시도정전심부유우응력증대，연변변형가극，취유가능발생실은파배。연구성과여생산실천구유교호적일치성，가이위와사추채삼수적학정제공이론지도。
In this paper, to investigate the stress distribution and movement law around gas drainage boreholes, the mechanical properties of coal mass around boreholes were analyzed, a visco-elastic plas-tic model considering the plastic softening and dilatancy was established, and the expressions of coal stress, displacement, pore size variation and pressure-relief range were obtained. In addition, the stress distributions and pressure-relief effects around drainage boreholes in the hard and soft coal seams were comparatively analyzed, the pore size variation rules of boreholes were studied, and the reason about rapid decay of borehole drainage concentration in soft seam was explained. The results show that the coal mass around boleholes have the properties of plastic softening, dilatancy and rheological. The boreholes in soft coal seam can get better pressure-relief effect, the creep deformation is more severely and the unstabe failure can occur in a short time, which will block the gas drainage channel, and result in rapid decline of gas drainage concentration. Meanwhile, the pore sizes of boreholes in hard coal seam are reduced somewhat, but still in stable state, and will not block the gas drainage channel. But, with the increase of ground pressure in deep minefield, the creep deformation will increase, and the unstabe failure may occur. The research results agree well with mining practice, which can provide theoretical guidance for the determination of gas drainage parameters.
