岩石力学与工程学报
巖石力學與工程學報
암석역학여공정학보
CHINESE JOURNAL OF ROCK MECHANICS AND ENGINEERING
2014年
7期
1319-1328
,共10页
采矿工程%近风氧化带%导水裂隙带高度%裂采比%发育机制
採礦工程%近風氧化帶%導水裂隙帶高度%裂採比%髮育機製
채광공정%근풍양화대%도수렬극대고도%렬채비%발육궤제
mining engineering%approaching to weathered and oxidized zone%height of water transmitting zone%ratio of the height of the fractured zone to the mining height%developing mechanism
为寻求提高开采上限导高发育规律,以40例“两带”探测钻孔实测数据为依据,应用回归分析方法对3种水体采动等级下不同覆岩类型的导水裂隙高度进行非线性统计研究,并首次建立3类水体下的预留防水煤岩柱与裂采比间的BoxLucas1模型曲线。研究发现:提高开采上限时,BoxLuca1曲线预测导水高度的误差值远小于常规“三下”规程经验公式误差,表明该模型的合理性;3类水体的曲线斜率逐渐增大,顺序为II,III类>I类,表明II,III类裂采比下降更快,导高发育受到风氧化带的抑制作用更加明显。而且I,II类水体下的导水裂隙顶界面未达到泥化层的底界面,III类水体下的裂隙未达到或未穿透风氧化带。说明在一定范围内提高开采上限是可行的。在此基础上,一方面利用Paris位移公式和Crouch不连续位移公式,提出风氧化带拉张型裂隙面的位移公式,计算结果表明,该带裂隙受上覆自重应力影响更容易因发生变形位移和刚度位移而产生弥合效应。另一方面,风氧化带特有的塑性大变形使得外力对该带所做的功大部分被其消耗掉,因而更容易损耗劈裂能量,从而抑制导水裂隙的继续向上发育。这可为该带下合理留设防水煤岩柱提高煤层开采上限提供理论依据。
為尋求提高開採上限導高髮育規律,以40例“兩帶”探測鑽孔實測數據為依據,應用迴歸分析方法對3種水體採動等級下不同覆巖類型的導水裂隙高度進行非線性統計研究,併首次建立3類水體下的預留防水煤巖柱與裂採比間的BoxLucas1模型麯線。研究髮現:提高開採上限時,BoxLuca1麯線預測導水高度的誤差值遠小于常規“三下”規程經驗公式誤差,錶明該模型的閤理性;3類水體的麯線斜率逐漸增大,順序為II,III類>I類,錶明II,III類裂採比下降更快,導高髮育受到風氧化帶的抑製作用更加明顯。而且I,II類水體下的導水裂隙頂界麵未達到泥化層的底界麵,III類水體下的裂隙未達到或未穿透風氧化帶。說明在一定範圍內提高開採上限是可行的。在此基礎上,一方麵利用Paris位移公式和Crouch不連續位移公式,提齣風氧化帶拉張型裂隙麵的位移公式,計算結果錶明,該帶裂隙受上覆自重應力影響更容易因髮生變形位移和剛度位移而產生瀰閤效應。另一方麵,風氧化帶特有的塑性大變形使得外力對該帶所做的功大部分被其消耗掉,因而更容易損耗劈裂能量,從而抑製導水裂隙的繼續嚮上髮育。這可為該帶下閤理留設防水煤巖柱提高煤層開採上限提供理論依據。
위심구제고개채상한도고발육규률,이40례“량대”탐측찬공실측수거위의거,응용회귀분석방법대3충수체채동등급하불동복암류형적도수렬극고도진행비선성통계연구,병수차건립3류수체하적예류방수매암주여렬채비간적BoxLucas1모형곡선。연구발현:제고개채상한시,BoxLuca1곡선예측도수고도적오차치원소우상규“삼하”규정경험공식오차,표명해모형적합이성;3류수체적곡선사솔축점증대,순서위II,III류>I류,표명II,III류렬채비하강경쾌,도고발육수도풍양화대적억제작용경가명현。이차I,II류수체하적도수렬극정계면미체도니화층적저계면,III류수체하적렬극미체도혹미천투풍양화대。설명재일정범위내제고개채상한시가행적。재차기출상,일방면이용Paris위이공식화Crouch불련속위이공식,제출풍양화대랍장형렬극면적위이공식,계산결과표명,해대렬극수상복자중응력영향경용역인발생변형위이화강도위이이산생미합효응。령일방면,풍양화대특유적소성대변형사득외력대해대소주적공대부분피기소모도,인이경용역손모벽렬능량,종이억제도수렬극적계속향상발육。저가위해대하합리류설방수매암주제고매층개채상한제공이론의거。
Nonlinear statistical analysis of heights of zones with water transmitting fractures at three different grades of underwater mining beneath various roof rocks was conducted with the regression method and the measured data of 40 drillings. A BoxLucas1 curve between the ratio of heights of fractured to mining zones and the height of waterproof coal pillar was established,which produced smaller errors than the conventional empirical formula did. The slopes of curves for 3 types of water gradually increased and the values of types II and III were greater than that of type I,which indicated that the height of water transmitted fractured zone under water mining type I was more easily reduced by the inhibition effect of weathered and oxidized zone. The fracture of type III did not penetrate the weathered and oxidized zone as mining closing to this area and the top interfaces of water transmitted fractures of types I and II did not reach the bottom of the mud layer,which indicated that raising the upper limit of mining within a certain range was feasible. A displacement formula for tensile fracture surfaces of weathered and oxidized zone was proposed utilizing Paris′s formula of displacement and Crouch′s formula of discontinuous displacement. The calculated results show that the fractures are more easily closed due to the overlying gravity. The large plastic deformation of weathered and oxidized zone consumes the work by external forces and consumes splitting energy easily,which prevents water transmitted fractures from upward development.