【正文】 t of gas of the B11 coal seam is , designed for 2000 t/d.The C13 coal seam is a protected layer, located 70m above the B11 coal seam. The corresponding test working face of the protected layer consists of the 21213 working face in East1 and the 23223 in East2 (called 21213/23223 bined). The strike is 1680 m (two faces in all) and the trend is 160 coal seam is ～ m thick, m on average,the dip angle 60～130 and 90 on average. The original measured gas pressure was MPa, the amount of gas (). The coal seam was also stable and its geological structure simple. By draining the pressure relief gas, the danger of outbursts in the C13 coal seam could be eliminated and the amount of gas was effectively prehensive，mechanized cover caving coal mining technology been adopted for this working face, which was signed for 5000 t/d.3 Drainage principle of pressure relief gasDraining of pressure relief gas is referred to as protective layer mining technology. When we mine coal seams in outburst coal mines, we should first mine the nonoutburst or low risk outburst coal seams as protective layers, where the outburst coal seam is then called the protected layer. With protective layer mining, the coal and rock mass among the roof and floor moves and deforms within certain limits,which causes stress changing. Fracture fields are redistributed, ground stress is reduced, the coal seam expands, the coal seam permeability coefficient increases and drainage condition are created for pressure relief gas in the protected coal seams. In the case of the Panyi mine, we drilled penetration boreholes or carried out surface well drilling to drain the pressure relief gas, which caused the amount of gas and pressure to decrease significantly and the coal mass turned hard. Naturally. eas pressure reduced to below , the amount of gas reauced to below a 6m3/t and the coal consistency coefficient rose 48%100%.At the end, the danger of outbursts was pletely eliminated from the protected layers and conditions for safe and highly efficient mining had been achieved. Drainage indices of pressure relief gas in the different ore areas are shown in Table 1.4 Drainage methods of pressure relief gasDrainage methods of pressure relief gas consist largely of draining gas from the protected layers affected by mining. The space between the protective working faces 23521 and 21213/23223 was about 70 m, which is really a long distance below the protective layer mining. We have often used surface well drilling and upper penetration boreholes located in floor roadways to drain pressure relief gas from the underside of the protective mining layer. Surface well drilling is unreliable and we often used penetration boreholes. The design of penetration boreholes includes the construction of a floor roadway, a suction drilling field and upper penetration boreholes Technology, 2008, 37(2):236240. (In Chinese).[4] Cheng Y P, Yu Q X, Yuan L, Li P, Liu Y Q, Tong Y research of safe and highefficient exploitation of coal and pressure relief gas in long of China University of Mining amp。為了能夠有效地釋放瓦斯壓力，消除瓦斯突出的風(fēng)險(xiǎn)，我們使用一個(gè)特定數(shù)量的滲透鉆孔抽瓦斯。關(guān)鍵詞：保護(hù)層 技術(shù)原理 引流減壓瓦斯 工程應(yīng)用1引言 隨著開(kāi)采深度的增加,瓦斯的含量量和壓力增加,瓦斯災(zāi)難變得更加嚴(yán)重些，一些淺和不爆發(fā)的煤層也逐漸變成突出煤層。通常,煤層的低滲透系數(shù)低，例如,平均來(lái)說(shuō),～1m2/()，它目前最大的困難在提前排出瓦斯控制在煤層中發(fā)生瓦斯突出。大量的突出事故發(fā)生在開(kāi)采中,包括一個(gè)重大瓦斯爆炸事故,所以在開(kāi)采這個(gè)煤層之前，控制瓦斯含量非常重要。～13176。相應(yīng)測(cè)試開(kāi)采層的保護(hù)護(hù)層由東1礦區(qū)的21213工作面和東2礦區(qū)（21213工作面/23223工作面的總和）構(gòu)成,開(kāi)采煤層是深度從160m到1600m包含兩層煤。/ t，～l㎡/(MPa178。當(dāng)我們?cè)谝装l(fā)生瓦斯爆炸的煤礦開(kāi)采時(shí)，我們首先把不發(fā)生突出或著低煤層突出危險(xiǎn)的煤層作為保護(hù)層，那些突出煤層的地方被稱為被保護(hù)層。當(dāng)然，.，氣體量減少到低于6m179。保護(hù)層開(kāi)采的是23521工作面和21213/23223工作面間距有70m，這是低于保護(hù)層開(kāi)采的距離?；诿簩訔l件和具體的地質(zhì)條件，巷道在C13煤層以下10～20米較好的巖層里布置或在C13煤層以上46～56米較好的巖層。在23223工作面,51鉆場(chǎng)已經(jīng)建成，遠(yuǎn)離C13煤層巷道禁止線，在減壓區(qū)，每一個(gè)區(qū)段的設(shè)置是40m。每個(gè)鉆鉆場(chǎng)沿著減壓區(qū)的方向打4個(gè)鉆，每個(gè)鉆的間距是40m，它被安置在煤層厚表層的中間。圖1鉆場(chǎng)和泄壓面積5泄壓水平 保護(hù)層被開(kāi)采后，被保護(hù)層層移動(dòng)和變形，從而導(dǎo)致地應(yīng)力降低，透氣性系數(shù)增加和使煤層泄壓。開(kāi)始，我們?cè)贑13煤層頂板和地板鉆一個(gè)鉆孔來(lái)看是否變形，然后安裝測(cè)試點(diǎn)由兩個(gè)試驗(yàn)點(diǎn)的相對(duì)位移。利用殘余瓦斯量及鉆孔瓦斯涌入，（）增加了近2880倍，這表明現(xiàn)在C13煤層中的氣體達(dá)到了很容易抽放的條件 。瓦斯抽放2080天之間的時(shí)期是活躍的時(shí)期，壓力活動(dòng)和滲透率達(dá)到了最大。圖3瓦斯抽放與時(shí)間的關(guān)系2）瓦斯抽放總量和殘余瓦斯含量瓦斯抽放總量，包括從滲透鉆孔排出的量和排放在回風(fēng)巷道的瓦斯。當(dāng)保護(hù)工作面超前過(guò)去400米的壓力孔測(cè)量，保持穩(wěn)定，這表明。B11煤層開(kāi)采后，％％最大相對(duì)膨脹變形。在C13煤層瓦斯排除后，C13煤層的瓦斯量有效降低，％以上。2程遠(yuǎn)平 俞啟香 煤層群煤與瓦斯安全高效共采體系及應(yīng)用 《中國(guó)礦業(yè)大學(xué)學(xué)報(bào)》 2003年第05期。 6俞啟香 礦井瓦斯防治 中國(guó)礦業(yè)大學(xué)出版社1992。21