孫魁 夏玉成 李成
摘 要:為評價(jià)綜放開采條件下煤層頂板涌(突)水危險(xiǎn)性,以焦坪礦區(qū)某井田為例,通過水質(zhì)分析和導(dǎo)水裂隙帶發(fā)育高度分析相結(jié)合的方法,對礦井頂板涌(突)水水源進(jìn)行了判定,同時(shí)在基于GI-變異系數(shù)法的含水層富水性分析,基于砂泥巖分布圖的離層發(fā)育危險(xiǎn)性分析和基于裂采比的冒裂安全性分析的基礎(chǔ)上,通過疊加分析對頂板涌(突)水危險(xiǎn)性進(jìn)行了評價(jià)。結(jié)果表明:礦井頂板涌(突)水水源為白堊系下統(tǒng)洛河組下段砂巖裂隙潛水含水層水,以及發(fā)育在宜君組粗礫巖與直羅組頂部泥巖之間離層空間內(nèi)的離層水。頂板涌(突)水危險(xiǎn)的區(qū)域主要分布在井田中部和西部,其中中部的一、二盤區(qū)由于煤層采厚較大,導(dǎo)水裂隙帶突破洛河組底界的范圍較廣,頂板涌(突)水危險(xiǎn)性最大,且存在局部離層強(qiáng)突水區(qū);井田西部三、四盤區(qū)主要為頂板涌(突)水中等危險(xiǎn)區(qū);井田東北部五盤區(qū),大部分區(qū)域?yàn)橄鄬Π踩珔^(qū),局部存在含水層突水中等危險(xiǎn)區(qū)。
關(guān)鍵詞:地質(zhì)資源與地質(zhì)工程;頂板水害;疊加分析;GI-變異系數(shù)法;突水危險(xiǎn)性評價(jià)
中圖分類號:TD 163 文獻(xiàn)標(biāo)志碼:A
DOI:10.13800/j.cnki.xakjdxxb.2019.0310 文章編號:1672-9315(2019)03-0452-09
Abstract:In order to evaluate the risk assessment of water inflow (inrush) from coal seam roof under fully mechanized caving mining, a mine field in Shaanxi Jiaoping mining area was taken as an example,the water source of the mine roof surge is determined by the method of water quality analysis and the development height analysis of the water conducting fracture zone.At the same time, on the basis of the water rich analysis based on the GI-variation coefficient method risk analysis of the separation development based on the sand shale distribution map,and safety analysis of fissure mining ratio,the risk of roof water inrush is evaluated by superposition analysis.The results indicate that the water source of the mine roof is the water in the lower section of the lower Cretaceous Luohe formation sandstone fissure dive aquifer,and the separated layer water developed in the separation space between the coarse conglomerate and the mudstone of the diojun group.The area of the roof inflow(inrush)water is mainly distributed in the middle and west of the well field.In the first and second panel of the middle part,the coal seam has a great thickness,and the water guide belt breaks through the wide range of the bottom of the Luohe group,so the risk of water inflow(inrush)from coal seam roof is the biggest.In addition,there is a local strong outburst area of abscission layer of water.The third or fourth panel of the west part is mainly dangerous areas.Most of the fifth panel in the northeast part of the mine area are relative safety areas,and the other is the middle dangerous area of abscission layer of water inrush.Key words:geological resources and geological engineering;roof water hazard;superposition analysis;GI-variation coefficient method;risk assessment of water inrush
0 引 言厚煤層綜放開采條件下,頂板覆巖破壞強(qiáng)烈,如果對頂板含水層分布及發(fā)育特征認(rèn)識不足,往往會(huì)造成嚴(yán)重的頂板水害事故和水資源滲漏[1-6]。由于頂板突水事故水源多樣,征兆不明顯,突水量大,危害嚴(yán)重,因此,有效地評價(jià)煤層頂板水害危險(xiǎn)性,針對性地圈定頂板突水危險(xiǎn)區(qū),對煤礦頂板水害預(yù)測及防治具有十分重要的指導(dǎo)意義。在頂板水害預(yù)測方面,不少學(xué)者采用數(shù)值模擬計(jì)算和統(tǒng)計(jì)分析等方法,研究和量化目標(biāo)含水層富水性、導(dǎo)水裂隙帶高度以及地下水滲流特征等礦井突水因素。武強(qiáng)等提出了基于AHP的“三圖-雙預(yù)測”方法,并借助三維數(shù)值模型,從頂板冒裂程度和含水層富水性2個(gè)方面對煤層頂板含水層突水危險(xiǎn)性進(jìn)行了評價(jià)[7-11]。李坤、張小明、杜偉升等在“三圖”理論分析的基礎(chǔ)上,建立了基于GIS與AHP綜合分析法的煤層頂?shù)装逯聻?zāi)含水層富水性指數(shù)模型[12-14]。任曉波等對傳統(tǒng)的“三圖-雙預(yù)測法”進(jìn)行了改進(jìn)和修正,并在具體的礦井頂板涌(突)水危險(xiǎn)性評價(jià)中,取得了較好的應(yīng)用效果[15]。范立民等研究了突水潰砂機(jī)理,并采用基于GIS的多信息融合方法,對陜北神府礦區(qū)突水潰沙危險(xiǎn)性進(jìn)行了綜合分區(qū)[16]。王生全等運(yùn)用層次分析法,對青龍寺煤礦5-2煤層頂板含水層突水危險(xiǎn)性進(jìn)行了評價(jià)[17]。賀曉浪等采用層次分析、模糊聚類等方法,提出了陜北毛烏素沙漠區(qū)潛水含水層富水性評價(jià)模型[18]。
馬雄德等將煤層賦存特征和開采條件作為頂板突水危險(xiǎn)性分區(qū)評價(jià)的2大因素[19]。代革聯(lián)等從頂板砂巖物質(zhì)組成、孔隙特征、滲流特征、富水性等方面對頂板含水層涌(突)水危險(xiǎn)性進(jìn)行評價(jià)[20]。張海榮等在缺少煤層頂板水文地質(zhì)信息且無法判明突水規(guī)律的情況下,嘗試采用GIS復(fù)合分析的方法對煤層頂板水害進(jìn)行評價(jià)預(yù)測,并取得了良好的實(shí)際應(yīng)用效果[21]。以上不同學(xué)者從不同角度研究了煤層頂板突水危險(xiǎn)性的評價(jià)預(yù)測方法。筆者在前人研究成果的基礎(chǔ)上,以陜西焦坪礦區(qū)某井田為例,在分析水文地質(zhì)特征的基礎(chǔ)上,對頂板水害致災(zāi)水源進(jìn)行了判定,從含水層富水性、離層發(fā)育危險(xiǎn)性和冒裂安全性3個(gè)方面進(jìn)行綜合分析,對煤層頂板涌(突)水危險(xiǎn)性進(jìn)行了分區(qū)評價(jià),為煤礦頂板水害防治提供理論支持。
1 水文地質(zhì)特征井田位于陜西焦坪礦區(qū)南部,礦井主采4-2號煤層,厚度0~31.53 m.煤層頂板主要含水層自下而上分別為侏羅系中下統(tǒng)直羅-延安組砂巖裂隙含水層、白堊系下統(tǒng)洛河組下段砂巖裂隙潛水含水層、白堊系下統(tǒng)洛河組上段砂巖裂隙潛水含水層、白堊系下統(tǒng)華池-環(huán)河組砂巖裂隙潛水含水層、第四系含泥質(zhì)砂卵石潛水含水層。井田東部一盤區(qū)4-2煤層平均采厚約12 m,綜采采煤工藝,全部垮落法管理頂板。在一盤區(qū)中部1412,1418工作面回采時(shí),水害事故頻發(fā),共發(fā)生過9次突水(表1),頂板水害已經(jīng)嚴(yán)重威脅了礦井的安全生產(chǎn)。
1)突水量大,周期短。2010年12月至2013年5月發(fā)生過9次頂板突水突事故,最大礦井涌水量249~2 000 m3/h,涌水量較大。每次突水的時(shí)間間隔一般為60 d;
2)突水水源穩(wěn)定。根據(jù)井下突水點(diǎn)所取水樣的水質(zhì)檢測結(jié)果,致災(zāi)水源為洛河組下段砂巖裂隙潛水含水層和直羅-延安組砂巖裂隙潛水含水層;
3)突水點(diǎn)位置較為集中。1412,1418兩工作面9次突水點(diǎn)的位置較為集中,距離間隔一般為160 m.綜上分析可知,礦井突水量大小、突水次數(shù)、突水水源穩(wěn)定性和突水點(diǎn)位置分布等,均具有典型離層突水的特點(diǎn)。
2 礦井涌(突)水水源為了更加準(zhǔn)確的判別頂板水害致災(zāi)水源,筆者從水質(zhì)化驗(yàn)結(jié)果和導(dǎo)水裂隙帶發(fā)育高度2個(gè)方面分別進(jìn)行分析。2.1 水質(zhì)分析1412,1418工作面發(fā)生突水后,為了更好的判別水源,工作人員在工作面突水點(diǎn)和采空區(qū)共采集了水樣5份,對水中的K++Na+,Ga2+,Mg2+,Cl-,SO2-4,HCO-3,TDS等7個(gè)指標(biāo)進(jìn)行了化驗(yàn)分析,化驗(yàn)結(jié)果見表2.根據(jù)井下采集水樣的水質(zhì)化驗(yàn)結(jié)果,繪制水質(zhì)Piper三線圖(圖1),根據(jù)主要陰陽離子分布位置的差異,可以直觀的反映出各水樣點(diǎn)水化學(xué)類型的差異。
2.2 導(dǎo)水裂隙帶通過上述水質(zhì)分析結(jié)果,可以明確的判定出頂板突水的水源穩(wěn)定,為上部砂巖裂隙含水層水。為了更加準(zhǔn)確具體的判別致災(zāi)水源的層位,要對導(dǎo)水裂隙帶的發(fā)育高度進(jìn)行分析。根據(jù)文獻(xiàn)[22-23]中的計(jì)算機(jī)數(shù)值模擬結(jié)果和礦方實(shí)際的探測資料,導(dǎo)水裂隙帶高度與煤層采厚的比值約為19.5,導(dǎo)通至白堊系下統(tǒng)洛河組下段砂巖裂隙潛水含水層。由此可知,礦井致災(zāi)含水層為侏羅系中下統(tǒng)直羅-延安組砂巖裂隙潛水含水層和白堊系下統(tǒng)洛河組下段砂巖裂隙潛水含水層。由于前者直羅-延安組含水層厚度相對較小,富水性較弱,水量有限,對礦井涌水量的影響不大。而后者洛河砂巖潛水含水層為河流相沉積,富水性好,存在局部富水區(qū),且以凈儲量為主,是礦井突水的主要充水水源。通過上述水質(zhì)分析和導(dǎo)水裂隙帶導(dǎo)通層位的分析結(jié)果可知,礦井突水水源穩(wěn)定,主要來自白堊系下統(tǒng)洛河組下段砂巖裂隙潛水含水層。3 涌(突)水危險(xiǎn)性評價(jià)充水水源和充水通道是煤礦頂板涌(突)水的2大必要條件。由前述分析可知,充水水源主要是白堊系下統(tǒng)洛河組下段砂巖裂隙潛水含水層,同時(shí),根據(jù)一盤區(qū)工作面突水特征分析結(jié)果和文獻(xiàn)[22-23]的研究成果,該礦井還存在明顯的離層突水特征。能夠引起礦井較大涌水,甚至導(dǎo)致離層水害事故的可致災(zāi)離層空間主要發(fā)育在宜君組粗礫巖和下位直羅組頂部泥巖之間(圖2)。對于充水通道,該礦井地質(zhì)構(gòu)造相對簡單,未發(fā)現(xiàn)大型的導(dǎo)水構(gòu)造,因此可以判定采動(dòng)引起的導(dǎo)水裂隙帶是煤層頂板涌(突)水的主要充水通道。文中通過對洛河組下段砂巖裂隙含水層富水性、離層發(fā)育危險(xiǎn)性、冒裂安全性分別進(jìn)行評價(jià)分區(qū),并將3個(gè)分區(qū)結(jié)果進(jìn)行疊加分析,對頂板涌(突)水危險(xiǎn)性進(jìn)行綜合性評價(jià)。
3.1 主控因素富水性文中選取洛河組下段砂巖裂隙潛水含水層的厚度、巖芯采取率、沖洗液漏失量、單位涌水量和滲透系數(shù)5個(gè)主控因素,根據(jù)井田勘探時(shí)期鉆孔數(shù)據(jù),分別做出專題圖。采用G1-變異系數(shù)法對各主控因素進(jìn)行賦權(quán),構(gòu)建評價(jià)目標(biāo)含水層富水性大小的綜合指數(shù),即富水性指數(shù),然后進(jìn)行綜合性評價(jià)分區(qū)。3.1.1 主控因素的建立
1)含水層厚度。通常情況下,若其它因素一定,含水層越厚,則含水量越大,富水性就越好。根據(jù)井田內(nèi)洛河組下段砂巖裂隙含水層厚度統(tǒng)計(jì)數(shù)據(jù)繪制出含水層厚度等值線圖(圖3(a));
2)巖芯采取率。通常情況下,巖芯采取率越低,說明巖層較為破碎,裂隙較發(fā)育,儲水能力和導(dǎo)水能力越好,富水性越強(qiáng)。根據(jù)巖芯采取率繪制等值線圖(圖3(b));
3)沖洗液漏失量。一般情況下,沖洗液漏失量越大,說明巖層的孔隙性越好,富水性越強(qiáng)。根據(jù)沖洗液漏失量繪制等值線圖(圖3(c));
4)單位涌水量。是直觀反映含水層富水性的重要參數(shù),單位涌水量越大,含水層富水性及其與其他含水層的相互補(bǔ)給關(guān)系就越好。根據(jù)井田內(nèi)水文鉆孔的抽水實(shí)驗(yàn)結(jié)果,繪制等值線圖(圖3(d));
5)滲透系數(shù)。是反映巖土體滲透能力的重要參數(shù)。滲透系數(shù)越大,說明巖土體的滲透能力越強(qiáng),富水性也越強(qiáng)。根據(jù)井田內(nèi)水文鉆孔的抽水試驗(yàn)結(jié)果,繪制等值線圖(圖3(e))。
3.1.2 權(quán)重確定
4 結(jié) 論
1)采用水質(zhì)分析與導(dǎo)水裂隙帶發(fā)育高度分析相結(jié)合的方法,判定煤層頂板涌(突)水的主要致災(zāi)水源為白堊系下統(tǒng)洛河組下段砂巖裂隙潛水含水層。煤層頂板可致災(zāi)離層空間發(fā)育在宜君組粗礫巖和直羅組頂部泥巖之間。
2)通過含水層富水性分區(qū)圖、離層發(fā)育危險(xiǎn)性分區(qū)圖和頂板冒裂安全性分區(qū)圖的復(fù)合疊加分析結(jié)果,礦井涌(突)水危險(xiǎn)區(qū)主要分布在井田中部和西部,其中,中部一、二盤區(qū)礦井涌(突)水危險(xiǎn)性最大,且存在局部強(qiáng)離層突水區(qū)。井田東北部和西南部礦井涌(突)水危險(xiǎn)性小,大部分為相對安全區(qū)。
參考文獻(xiàn)(References):
[1] 武 強(qiáng),崔芳鵬,趙蘇啟,等.礦井水害類型劃分及主要特征分析[J].煤炭學(xué)報(bào),2013,38(4):561-565.WU Qiang,CUI Fang-peng,ZHAO Su-qi,et al.Type classification and main characteristics of mine water disasters[J].Journal of China Coal Society,2013,38(4):561-565.
[2]王雙明,黃慶享,范立民,等.生態(tài)脆弱礦區(qū)含(隔)水層特征及保水開采分區(qū)研究[J].煤炭學(xué)報(bào),2010,35(1):8-14.WANG Shuang-ming,HUANG Qing-xiang,F(xiàn)AN Li-mini,et al.Study on overburden aquclude and water protection mining regionazation in the ecological fragile mining area[J].Journal of China Coal Society,2010,35(1):8-14.
[3]范立民,馬雄德,冀瑞君.西部生態(tài)脆弱礦區(qū)保水采煤研究與實(shí)踐進(jìn)展[J].煤炭學(xué)報(bào),2015,40(8):1711-1717.FAN Li-min,MA Xiong-de,JI Rui-jun.Progress in engineering practice of water-preserved coal mining in western eco-environment frangible area[J].Journal of China Coal Society,2015,40(8):1711-1717.
[4]范立民.保水采煤的科學(xué)內(nèi)涵[J].煤炭學(xué)報(bào),2017,42(1):27-35.FAN Li-min.Scientific connotation of water-preserved mining[J].Journal of China Coal Society,2017,42(1):27-35.
[5]FAN Li-min,MA Xiong-de.A review on investigation of water-preserved coal mining in western China[J]. International Journal of Coal Science & Technology,2018,5(4):411-416.
[6]柳 寧,趙曉光,解海軍,等. 榆神府地區(qū)煤炭開采對地下水資源的影響[J].西安科技大學(xué)學(xué)報(bào),2019,39 (1):71-78.LIU Ning,ZHAO Xiao-guang,XIE Hai-jun,et al. Influence of coal mining on groundwater resources in Yushenfu Area[J].Journal of Xi’an University of Science and Technology,2019,39(1):71-78.
[7]武 強(qiáng),黃曉玲,董東林,等.評價(jià)煤層頂板涌(突)水條件的“三圖-雙預(yù)測法”[J].煤炭學(xué)報(bào),2000,25(1):60-65.WU Qiang,HUANG Xiao-ling,DONG Dong-lin,et al.“Three maps-two predictions” method to evaluate water bursting coditions on roof coal[J].Journal of China Coal Society,2000,25(1):60-65.
[8]武 強(qiáng),許 珂,張 維.再論煤層頂板涌(突)水危險(xiǎn)性預(yù)測評價(jià)的“三圖-雙預(yù)測法”[J].煤炭學(xué)報(bào),2016,41(6):1341-1347.WU Qiang,XU Ke,ZHANG Wei.Further research on “three maps-two predictions”method for prediction on coal seam roof water bursting risk[J].Journal of China Coal Society,2016,41(6):1341-1347.
[9]Wu Q,F(xiàn)an S K,Zhou W F,et al.Application of the analytic hierarchy process to assessment of water inrush:A case study for the No.17 coal seam in the sanhejian coal mine,China[J].Mine Water and the Environment,2013,32(3):229-238.
[10]Wu Q,Liu Y Z,Zhou W F,et al.Assessment of water inrush vulnerability from overlying aquifer using GIS-AHP-based “three maps-two predictions” method:a case study in Hulusu coal mine,China[J].Quarterly Journal of Engineering Geology and Hydrogeology,2015,48(3-4):234-243.
[11]Wu Q,Liu Y Z,Zhou W F,et al.Evaluation of water inrush vulnerability from aquifers overlying coal seams in the menkeqing coal mine,China[J].Mine Water and the environment,2015,34(3):258-269.
[12]李 坤,曾一凡,尚彥軍,等.基于GIS的“三圖-雙預(yù)測法”的應(yīng)用[J].煤田地質(zhì)與勘探,2015,43(2):58-62.LI Kun,ZENG Yi-fan,SHANG Yan-jun,et al.The application of “three maps-two predictions” method based on GIS[J].Coal Geology & Eeploration,2015,43(2):58-62.
[13]張小明,武強(qiáng),劉紅艷,等.集賢井田煤層頂板危險(xiǎn)性綜合評價(jià)與防治對策研究[J].煤炭工程,2016,48(S2):56-59.ZHANG Xiao-ming,WU Qiang,LIU Hong-yan,et al.Comprehensive evaluation for water hazard risk in coal seam roof of Jixian Mining Field and the preventive countermeasures[J].Coal Eegineering,2016,48(S2):56-59.
[14]DU Wei-sheng,JIANG Yao-dong,MA Zhen-qian,et al.Assessment of water inrush and factor sensitivity analysis in an amalgamated coal mine in China[J].Arabian Journal of Geosciences,2017,10(21).
[15]任曉波,吳瑞芳.基于煤層頂板充水含水層水壓的“修正三圖-雙預(yù)測法”研究[J].煤炭工程,2016,48(S2):131-133.REN Xiao-bo,WU Rui-fang.A modified three graphics-two predictions method based on hydraulic pressure of aquifers above coal seam roof[J].Coal Engineering,2016,48(S2):131-133.
[16]范立民,馬雄德,蔣 輝,等.西部生態(tài)脆弱礦區(qū)礦井突水潰沙危險(xiǎn)性分區(qū)[J].煤炭學(xué)報(bào),2016,41(3):531-536.FAN Li-min,MA Xiong-de,JIANG Hui,et al.Risk evaluation on water and sand inrush in ecologically fragile coal mine[J].Journal of China Coal Society,2016,41(3):531-536.
[17]王生全,武 超,彭 濤,等. 青龍寺煤礦5-2煤層頂板含水層突水危險(xiǎn)性評價(jià)[J].西安科技大學(xué)學(xué)報(bào),2018,38(6):959-965.WANG Sheng-quan,WU Chao,PENG Tao,et al.Evaluation of water inrush hazard in roof aquifer of 5-2 coal seam in Qinglongsi coal mine[J].Journal of Xi’an University of Science and Technology,2018,38(6):959-965.
[18]賀曉浪,段中會(huì),苗霖田,等. 陜北毛烏素沙漠區(qū)潛水含水層富水性及動(dòng)態(tài)變化特征[J].西安科技大學(xué)學(xué)報(bào),2019,39(1):88-95.HE Xiao-lang,DUAN Zhong-hui,MIAO Lin-tian,et al.Unconfined aquifer water-richness and dynamic change features of Mu Us Desert Area in northern Shaanxi[J].Journal of Xi’an University of Science and Technology,2019,39(1):88-95.
[19]馬雄德,范立民,賀衛(wèi)中,等.淺埋煤層高強(qiáng)度開采突水危險(xiǎn)性分區(qū)評價(jià)[J].中國煤炭,2015,41(10):33-36.MA Xiong-de,F(xiàn)AN Li-min,HE Wei-zhong,et al.Zoning and evaluation on water inrush risk in shallow coal seam with high intensity mining[J].China Coal,2015,41(10):33-36.
[20]代革聯(lián),薛小淵,牛 超.基于水化學(xué)特征分析的象山礦井突水水源判別[J].西安科技大學(xué)學(xué)報(bào),2017,37(2):213-218.DAI Ge-lian,XU Xiao-yuan,NIU Chao.Discrimination of water inrush source in Xiangshan coal mine based on chemical characteristics of groundwater[J].Journal of Xi’an University of Science and Technology,2017,37(2):213-218.
[21]張海榮,周榮福,郭達(dá)志,等.基于GIS復(fù)合分析的煤礦頂板水害預(yù)測研究[J].中國礦業(yè)大學(xué)學(xué)報(bào),2005,34(1):112-116.ZHANG Hai-rong,ZHOU Rong-fu,GUO Da-zhi,et al.Investigation on predicting roof water gush in coal mines based on multi-factor analysis[J].Journal of China University of Mining & Technology,2005,34(1):112-116.
[22]孫 魁.煤礦水害致災(zāi)機(jī)理研究[D].西安:西安科技大學(xué),2016.SUN Kui.Study on disaster-causing mechanism of coal mine flood[D].Xi’an:Xi’an University of Science and Technology,2016.
[23]孫 魁,王 英,李 成,等.巨厚煤層頂板離層水致災(zāi)機(jī)理研究[J].河南理工大學(xué)學(xué)報(bào)(自然科學(xué)版),2018,37(2):14-21.SUN Kui,WANG Ying,LI Cheng,et al.Mechanism of roof separation water disaster in thick coal seam[J].Journal of Henan Polytechnic University(Natural Science),2018,37(2):14-21.
[24]許 武,夏玉成,杜榮軍,等.導(dǎo)水裂隙帶預(yù)計(jì)經(jīng)驗(yàn)公式的“三性”探究[J].礦業(yè)研究與開發(fā),2013,33(6):63-67.XU Wu,XIA Yu-cheng,DU Rong-jun,et al.Study on three properties of the empirical formula for estimating the height of water-flowing fractured zone[J].Mining R & D,2013,33(6):63-67.
[25]方 剛,靳德武.銅川玉華煤礦頂板離層水突水機(jī)理與防治[J].煤田地質(zhì)與勘探,2016,44(3):57-64.FANG Gang,JIN De-wu.Research on the roof stratifugic water inrush mechanism and control in Tongchuan Yuhua coal mine[J].Coal Geology & Exploration,2016,44(3):57-64.