采礦學(xué)王莊煤礦論文設(shè)計(jì)

精品文檔歡迎下載目錄一般局部TOC\o"1-3"\h\u306091礦區(qū)概述及井田地質(zhì)特征 ②監(jiān)測(cè)數(shù)據(jù)可作為修改、完善錨桿支護(hù)初始設(shè)計(jì)數(shù)據(jù)的依據(jù)之一。頂板離層指示儀實(shí)際上是兩點(diǎn)巷道圍巖位移計(jì)。在頂板鉆孔中布置兩個(gè)測(cè)點(diǎn)，一個(gè)在圍巖深部穩(wěn)定處，一個(gè)在錨桿端部圍巖中。離層值就是圍巖中兩測(cè)點(diǎn)之間以及錨桿端部圍巖與巷道頂板外表間的相對(duì)位移值，并可直觀(guān)顯示出相對(duì)位移值(離層量)的大小?！?〕位移量監(jiān)測(cè)，利用多點(diǎn)位移計(jì)來(lái)完成巖層深部位移監(jiān)測(cè)，多點(diǎn)位移計(jì)是監(jiān)測(cè)巷道在掘進(jìn)和受采動(dòng)影響的整個(gè)效勞期間深部圍巖變形隨時(shí)間變化情況的一種儀器。安設(shè)多點(diǎn)位移計(jì)的目的：了解巷道圍巖各局部不同深度的位移，巖層弱化和破壞的范圍〔離層情況、塑性區(qū)、破碎區(qū)的分布等〕；判斷錨桿與圍巖之間是否發(fā)生脫離，錨桿應(yīng)變是否超過(guò)極限應(yīng)變量；為修改錨桿支護(hù)設(shè)計(jì)提供依據(jù)。

4煤巷錨桿支護(hù)技術(shù)在王莊煤礦的應(yīng)用4.1王莊煤礦簡(jiǎn)介潞安集團(tuán)王莊煤礦設(shè)計(jì)生產(chǎn)能力為4.0Mt/a，立井單水平開(kāi)拓，準(zhǔn)備方式為帶區(qū)，煤層開(kāi)采方法為大采上下位放頂煤工藝，主采煤層為3號(hào)煤層，其中運(yùn)輸大巷和輔助運(yùn)輸大巷布置與巖層中，回風(fēng)大巷布置于煤層中，分帶斜巷長(zhǎng)度到達(dá)了2700m，煤巷錨桿支護(hù)技術(shù)對(duì)于礦井巷道支護(hù)平安顯得尤為重要。4.2錨桿支護(hù)技術(shù)在王莊礦的應(yīng)用4.2.1大巷支護(hù)王莊煤礦膠帶運(yùn)輸大巷、輔助運(yùn)輸大巷及回風(fēng)大巷支護(hù)方式均采用錨噴支護(hù)，即錨桿、噴射混凝土聯(lián)合支護(hù)，其中膠帶運(yùn)輸大巷和輔助運(yùn)輸大巷為半圓拱形斷面，膠帶運(yùn)輸大巷布置于巖層，設(shè)計(jì)掘進(jìn)斷面積為19.8m2，混凝土噴射厚度100mm，樹(shù)脂錨固劑加固，錨桿排列方式為三花式，錨桿間距800mm，示意見(jiàn)圖4-1；圖4-1膠帶運(yùn)輸大巷斷面示意圖回風(fēng)大巷沿煤層頂板掘進(jìn)，為矩形斷面，凈斷面18.3m2，混凝土噴射厚度100mm，樹(shù)脂錨固劑加固，錨桿長(zhǎng)度2200mm，外露端100mm，錨桿排列方式為三花式，錨桿間距800mm，示意圖見(jiàn)圖4-2。圖4-2回風(fēng)大巷斷面示意圖4.2.2回采巷道支護(hù)王莊煤礦東一帶區(qū)，各分帶斜巷斷面形狀及支護(hù)特征均相同：為錨網(wǎng)索組合鋼帶支護(hù)，矩形斷面。斜巷均寬4.8m，高為3.5m，掘進(jìn)斷面15.75m2?！?〕頂板支護(hù)W鋼帶組合錨桿支護(hù)，并進(jìn)行錨索補(bǔ)強(qiáng)。錨桿直徑Φ20mm，長(zhǎng)度2.2m，左旋無(wú)縱筋螺紋鋼錨桿〔高強(qiáng)度〕，樹(shù)脂加長(zhǎng)錨固，破斷力230kN，錨桿間排距800mm；WX220/3.0型鋼帶寬為220mm，長(zhǎng)4250mm，厚3mm；采用菱形金屬網(wǎng)護(hù)頂；單根鋼絞線(xiàn)錨索，長(zhǎng)6.3m，首采面安設(shè)在巷道頂脊線(xiàn)處，間距1.6m。托盤(pán)：采用拱形高強(qiáng)度托盤(pán)，規(guī)格為150×150×8mm。錨桿角度：靠近巷幫的頂板錨桿安設(shè)角度與頂板垂線(xiàn)成30度角，其余與頂板垂直。網(wǎng)片規(guī)格：采用鐵絲編織的菱形金屬網(wǎng)護(hù)頂，規(guī)格型號(hào)50×50mm、5.5×1.1m。〔2〕巷幫支護(hù)錨桿直徑Φ20mm，長(zhǎng)度2.2m，左旋無(wú)縱筋螺紋鋼錨桿〔高強(qiáng)度〕，樹(shù)脂加長(zhǎng)錨固，破斷力230kN，錨桿間排距800mm；錨桿角度：靠近頂板的巷幫錨桿安設(shè)角度與水平線(xiàn)成15°。幫支護(hù)最大滯后頂支護(hù)為3m，嚴(yán)禁空班支護(hù)。如出現(xiàn)幫破碎，幫錨桿必須跟頂支護(hù)。如圖4-3所示。圖4-3回采巷道斷面支護(hù)示意圖4.2.3礦區(qū)錨桿支護(hù)平安保障體系制度保障，依據(jù)?煤巷錨桿支護(hù)技術(shù)標(biāo)準(zhǔn)?，并結(jié)合王莊礦具體生產(chǎn)、地質(zhì)條件，聽(tīng)取各方技術(shù)人員的意見(jiàn)制定?王莊煤礦錨桿支護(hù)技術(shù)標(biāo)準(zhǔn)?，在地質(zhì)評(píng)估、支護(hù)設(shè)計(jì)、支護(hù)材料的選用、施工行為標(biāo)準(zhǔn)、施工質(zhì)量驗(yàn)收標(biāo)準(zhǔn)、數(shù)據(jù)監(jiān)測(cè)監(jiān)控以及錨桿支護(hù)人員技術(shù)培訓(xùn)等方面都制定了嚴(yán)格的規(guī)定，用以標(biāo)準(zhǔn)錨桿支護(hù)施工措施?！?〕管理保障，加強(qiáng)施工作業(yè)機(jī)械工具及材料的管理，組成檢查小組，定期對(duì)井下采掘巷道進(jìn)行支護(hù)質(zhì)量檢查，依據(jù)支護(hù)標(biāo)準(zhǔn)，如假設(shè)發(fā)現(xiàn)問(wèn)題或危險(xiǎn)征兆，及時(shí)反響至王莊礦平安部，采取相應(yīng)措施，并提出相關(guān)處理整改建議?！?〕技術(shù)保障，定期組織錨桿支護(hù)相關(guān)人員〔操作工、安監(jiān)員〕進(jìn)行培訓(xùn)，使得管理人員、施工人員具備可靠的錨網(wǎng)支護(hù)專(zhuān)業(yè)知識(shí)，提高技術(shù)水平?！?〕礦壓監(jiān)測(cè)預(yù)警機(jī)制，建立可靠完善的礦壓監(jiān)測(cè)監(jiān)控系統(tǒng)，吸收技術(shù)人員、管理人員，在回采、掘進(jìn)巷道內(nèi)礦壓顯現(xiàn)處安設(shè)礦壓監(jiān)測(cè)站，實(shí)時(shí)監(jiān)測(cè)，及時(shí)反響監(jiān)測(cè)結(jié)果，并對(duì)檢測(cè)結(jié)果進(jìn)行分析、處理，與對(duì)巷道平安提供監(jiān)測(cè)預(yù)防作用。

5煤巷錨桿支護(hù)技術(shù)的改良途徑5.1開(kāi)展現(xiàn)狀伴隨著技術(shù)開(kāi)展，需求增加，開(kāi)采深度也不斷增加，巷道埋深也隨之增加，地應(yīng)力也相應(yīng)加大，礦壓顯現(xiàn)明顯增加，伴之而來(lái)的是地質(zhì)條件的復(fù)雜和進(jìn)一步的惡化，這就對(duì)巷道支護(hù)技術(shù)提出了更高的要求。同時(shí)，采煤機(jī)械的自動(dòng)化與采煤方法的高效化開(kāi)展，綜采放頂煤、厚煤層一次采全高開(kāi)采技術(shù)的快速開(kāi)展和大面積應(yīng)用，對(duì)煤巷錨桿支護(hù)技術(shù)提出更高要求。全煤巷道和半煤巖巷、大斷面巷道、沿空掘巷及破碎圍巖巷道所占的比重越來(lái)越大，支護(hù)難度顯著加大，這無(wú)疑需要巷道支護(hù)技術(shù)作出更好更強(qiáng)的改變。5.2煤巷錨桿支護(hù)技術(shù)改良途徑〔1〕增強(qiáng)錨桿的初錨力，跟據(jù)相關(guān)資料說(shuō)明，國(guó)外煤巷錨桿初錨力在100kN以上，占錨桿極限載荷的一半以上，而我國(guó)煤巷錨桿的螺母安裝多為人為操作，一般初錨力為30kN以下，占錨桿極限載荷的五分之一。初錨力相對(duì)過(guò)小，降低了對(duì)圍巖的支護(hù)效果，不利于維持巷道圍巖的長(zhǎng)期穩(wěn)定。〔2〕加強(qiáng)煤層巷道巷幫支護(hù)是維持巷道圍巖穩(wěn)定的重要步驟。煤巷兩幫煤體一般較松散破碎，如果兩幫支護(hù)效果一般，常引起兩幫煤體發(fā)生松動(dòng)掉落，加大懸頂面積，易導(dǎo)致頂板破損，甚至冒落。因此，加強(qiáng)對(duì)巷道煤幫的支護(hù)顯得尤為重要，通?？梢圆扇〉募夹g(shù)措施有：采用強(qiáng)力錨桿，錨噴支護(hù)，配合網(wǎng)、梁形成聯(lián)合支護(hù)等?！?〕研發(fā)新型高強(qiáng)度錨桿也是增強(qiáng)煤巷錨桿支護(hù)效果的有效途徑?！?〕采用小孔徑錨索，提高錨固效果。當(dāng)頂板巖層比擬破碎的情況下，采用小孔徑錨索對(duì)其進(jìn)行支護(hù)，可有效的對(duì)頂板進(jìn)行加固支護(hù)，保持頂板巖層的長(zhǎng)期穩(wěn)定?！?〕推廣以錨桿支護(hù)為主的聯(lián)合支護(hù)形式，隨著開(kāi)采深度的加深，動(dòng)壓影響對(duì)處于軟巖層的圍巖影響較大，易發(fā)生變形，單一的錨桿支護(hù)已無(wú)法完全滿(mǎn)足巷道支護(hù)要求，所以對(duì)于地壓大的不穩(wěn)定的圍巖，聯(lián)合支護(hù)必不可少?！?〕加強(qiáng)頂板動(dòng)態(tài)檢測(cè)監(jiān)控，確保煤巷錨桿支護(hù)平安。根據(jù)國(guó)外經(jīng)驗(yàn)要制定相應(yīng)的檢測(cè)監(jiān)控標(biāo)準(zhǔn)，對(duì)錨桿支護(hù)狀態(tài)下的巷道頂板進(jìn)行準(zhǔn)確的實(shí)時(shí)監(jiān)控，及時(shí)掌握巷道圍巖的變形數(shù)據(jù)，一方面可以分析判斷圍巖動(dòng)態(tài)，發(fā)現(xiàn)異常及時(shí)采取加強(qiáng)支護(hù)措施，防止危險(xiǎn)發(fā)生；另一方面統(tǒng)計(jì)反響信息，依據(jù)數(shù)據(jù)修改設(shè)計(jì)參數(shù)，使巷道錨桿支護(hù)參數(shù)選擇更加科學(xué)合理。

6結(jié)論錨桿支護(hù)技術(shù)是煤炭開(kāi)采過(guò)程中的一項(xiàng)重要技術(shù)，具備大量的理論依據(jù)和實(shí)踐經(jīng)驗(yàn)，經(jīng)過(guò)50多年的開(kāi)展逐步成熟。錨桿支護(hù)技術(shù)為一種主動(dòng)支護(hù)形式，具有支護(hù)速度快、支護(hù)效果好、材料本錢(qián)低、工作人員勞強(qiáng)度小等優(yōu)點(diǎn)，并且可以與混凝土噴射、鋼帶〔W型、M型〕、金屬網(wǎng)、工字鋼梁、錨索等聯(lián)合使用，它的廣泛使用可以給煤礦企業(yè)帶來(lái)有效的平安支護(hù)保障和顯著的經(jīng)濟(jì)效益。平安有效的巷道支護(hù)是礦井平安生產(chǎn)、高產(chǎn)高效的重要保證，經(jīng)過(guò)多年開(kāi)展實(shí)踐證明，煤巷錨桿支護(hù)技術(shù)是煤礦平安高效生產(chǎn)不可或缺的，普遍應(yīng)用于國(guó)內(nèi)外礦井支護(hù)行業(yè)，是煤礦巷道的主要支護(hù)形式，代表了煤礦巷道支護(hù)技術(shù)的開(kāi)展方向。目前，隨著礦井開(kāi)采深度增加，圍巖條件變得愈發(fā)復(fù)雜，支護(hù)也相對(duì)困難，這需要在熟練應(yīng)用傳統(tǒng)錨桿支護(hù)工藝的根底之上，不斷開(kāi)發(fā)推廣新技術(shù)、新設(shè)備，才能保障礦井生存和平安生產(chǎn)。

參考文獻(xiàn)[1]侯朝炯,郭勵(lì)生,勾攀峰.煤巷錨桿支護(hù)[M].徐州:中國(guó)礦業(yè)大學(xué)出版社,1999.[2]康紅普,王金華.煤巷錨桿支護(hù)理論與成套技術(shù)[M].北京:煤炭工業(yè)出版社.2021.[3]馬念杰,侯朝炯.采準(zhǔn)巷道礦壓理論及應(yīng)用[M].北京:煤炭工業(yè)出版社,1995.[4]陸士良,湯雷,楊新安.錨桿錨固力與錨固技術(shù)[M].北京:煤炭工業(yè)出版社,1998.[5]程良奎,范景倫,韓軍等.巖土錨固[M].北京：中國(guó)建筑工業(yè)出版社,2003.[6]何滿(mǎn)朝,袁和生,靖洪文.中國(guó)煤炭錨桿支護(hù)理論與實(shí)踐[M].北京:科學(xué)出版社,2004.[7]范明建.錨桿預(yù)應(yīng)力與巷道支護(hù)效果的關(guān)系研究[D].北京:煤炭科學(xué)研究總院,2007.[8]陳東印.地下工程預(yù)應(yīng)力錨桿支護(hù)數(shù)值模擬分析[D].山東青島:山東科技大學(xué),2005.[9]康紅普,姜鐵明,高富強(qiáng).預(yù)應(yīng)力在錨桿支護(hù)中的作用[J].煤炭學(xué)報(bào),2007,32(7):673-678.[10]康紅普.軟巖回采巷道錨桿支護(hù)技術(shù)的開(kāi)展[A].軟巖工程專(zhuān)業(yè)委員會(huì)第二屆學(xué)術(shù)會(huì)議論文集[C].北京:1999.[11]康紅普.高強(qiáng)度錨桿支護(hù)技術(shù)的開(kāi)展與應(yīng)用[J].北京:煤炭科學(xué)技術(shù),2000,28(2):1-4.[12]侯朝炯.煤巷錨桿支護(hù)[M].徐州:中國(guó)礦業(yè)大學(xué)出版社,1999.[13]鞠文君,王澤進(jìn).測(cè)力錨桿研制與應(yīng)用技術(shù)[J].煤礦開(kāi)采,1997,增刊:54-57.[14]鞠文君.全長(zhǎng)錨固錨桿工況監(jiān)測(cè)方法[J].煤炭科學(xué)技術(shù),1998,(6):15-18.[15]孔恒,馬念杰.錨固技術(shù)及其理論研究現(xiàn)狀和方向[J].中國(guó)煤炭,2000,(4).精品文檔歡迎下載英文原文InvestigationintothedeformationofalargespanroadwayinsoftseamsanditssupporttechnologyFuJianqiua,b,FengChaoc,ShiJianjuna,*aSchoolofCivilandEnvironmentalEngineering,UniversityofScienceandTechnology,Beijing100083,ChinabGuangdongHongdaBlastingEngineeringCo.,Ltd.,Guangzhou510623,ChinacCrecElectrificationBureauXi’anRailwayEngineeringCo.,Ltd.,Xi’an710032,ChinaAbstract:Weinvestigatedthedeformationfailuremechanismofsurroundingrockfromtheaspectofengineeringsupportforaroadwayinseamswithsoftroofsandsoftfloorsandobservedthelargedisplacementoftheroadwayinthesesoftseams.Theresultshowsthatthedeformationareaisquitelarge,andsettlementoftheroofisevidentanddisplacementofthesidewallsisalsoobvious.Weconsideredrockbolt-cablecouplingforroadwaysupportinseamswithsoftroofsandfloors,inwhichthecableshouldbefixedatkeypositions.Aswell,wedesignedanoptimalschemetosupportaroadwayinsoftseamsoftheShizuishanSecondMineinNingxia,China.Fieldmonitoringresultsshowthatbolt-cablecouplingsupporthasachievedtheaimsofroadwaystabilitycontrolandminimizesdeformation.Keywords:Seamswithsoftroofsandfloors,Roadwaydeformation,Bolt-cablecouplingsupport,Fieldmonitoring1.IntroductionCoalprovidesmostoftheenergyforChina’seconomicgrowth.Buttheincreasingdemandforcoalaroundtheworldleadstoacontinuousdecreaseofthisresourcenearoronthesurfaceoftheearthwhichcanbeextractedeconomically.Hence,thetrendindevelopingminingtechnologyshouldbefocusedondeepmining,whichhasalreadybeenanimportantresearchfieldfortheinternationalminingindustry[1,2].Especially,softroadways,encounteredindeepminingtechnology,arebecomingoneofthemainchallengesrestrictingseriouscoalexploitation[3-7].Problemscausedbyroadwaysinseamswithsoftroofsandfloorshavebecomeprominentwithinsoftrockissues.Onceexcavated,thestabilityofroadwaysinsoftrockishardtomaintainduetoconstantdeformation,wheresecondarydeformationmayoccureventhoughtheroadwayitselfisstable[8].Forexample,intheXieyiMineadisplacementof800mmoccurredintherockofthemainroadway.Withhighinsitustress,themaximumdeformationofanundergroundpower-houseoftheErtanhydraulicpowerstationreached180mm.TheroadwayinamineoftheChenghecompanyisofatypicalsoft-rockroadwaywhereadeformationof300mmwasobserved.Inthesecases,hugerepairsandmaintenanceofroadwayswererequiredtosustainproduction.InordertocontrolroadwaydeformationintheChengheMine,aspecialsupportwasdesignedforalarge-spanroadwayinseamswithsoftroofsandfloors.Weinvestigatedtheapplicationofthisdesignandtheeffectofthissupportandtrustthatwehaveprovidedacontributiontocoalminesafety.2.Roadwaydeformationinsoftseamswithsoftroofsandfloors2.1.SoftseamswithsoftroofsandfloorsNormally,a“three-softroadway〞r(shí)eferstoroadwaysinmineswithsoftroofs,softcoalandsoftfloors[4].AsoftroofisclassifiedasaI-typeunstableroof.Therockoftheimmediateroofshowsfeaturessuchasconsiderablefracturedevelopment,brokenrockmassandlowcompressionstrength.Thisleadstothecollapseofroofsshortlyafterexcavation.Thecompressionstrengthofasoftfloorisverylow(lessthan4MPa),expandsandsoftenswhenitencounterswaterandheavesfrequently.SoftcoalreferstotheProtodyakonovscaleofhardness,rangingonlyfrom0.3to1.0,showingcharacteristicsofmanyjoints,instabilityandfragility.2.2.TheoryofsurroundingrockdeformationAstableandsaferoadwayisexcavatedinsoftseamsineitherofthefollowingtwoconditions:(1)nodeformationoccursinthesurroundingrock,or(2)smalldeformationoccursbutshowslittledamageinitsapplicationandtheprojectissafe.Hence,thestabilityofundergroundroadwaysinsoftseamsisdeterminedbytheinteractionoftwofactors:rockmassstrengthanditsdeformationcharacteristicsandthestressredistributioninthesurroundingrockafterexcavation.Thus,theprojectremainsstablewhenthefirstfactorprevailsoverthesecond.Changesinthestateofstressofprimaryrockafterexcavationcanbedescribedby:〔1〕whereσristheradialstressoftheroadwayafterexcavation;γtheunitweightofthesurroundingrock;Hthedepthoftheroadway;randr1arethelanewayradiusandinfluencedistancerespectively(theequivalentradiuscanbeusedastheinfluencedistance).AsshowninEq.(1),theradialstressnearthesidewallsisclosetozeroafterexcavation,whichresultsinvariationoftheelasticvolumetricstrainandrockcreepage.Withlowconfiningpressure,thestructuralplaneinthesoftrockexpands,whichchangesthehydro-geologicalconditionsofthesurroundingrock.Meanwhile,seepagewithinthefractureweakenstheintensityoftherockandacceleratesdilatationandsofteningoftherock.Asaresult,largeconvergencedisplacementappearsinthesurroundingrock.Roadwaysthereforeshowavarietyofdisplacements,e.g.roofsettlement,floorheave,vaultdisplacementandsidewallheaves.Furtherdeformationcanleadtoinstabilityoftheroadway,suchastensilefailureofroofsandsidewalls,shearcracksinroofs,floorheaveandrooffalls.Itshouldbeemphasizedthatseriousdeformationusuallyoccursattheintersectionofroofandsideswalls,whereroadwayfailureismostlikelywithouttimelysupport.2.3.DeformationofsurroundingrockinseamswithsoftroofsandfloorsFrominvestigatingextensiveprojects,theconclusionisreachedthatsurroundingrockdeformationinseamswithsoftroofsandfloorsshowsthefollowingfeatures:(1)largedisplacementsofrock,rapiddeformation,largeareaswithdeformationand(2)continuousdeformation.Rockrheologybecomesthedominantfeatureofroadwaydeformationwiththefollowingcharacteristicsinthesurroundingrock.(1)Temporarynaturalstabilizationandfastcompression;(2)Large,fastandcontinuousdeformation;(3)Hoopandasymmetricalcompressionandviolentfloorheave;(4)Normalrigidsupportbecomessusceptible.3.SupportofroadwayinsoftseamsPlasticdeformationusuallyresultsincertaindiscordantareaswithinthesurroundingrock.However,couplingsupportcaneffectivelyreinforcesupportforanchormeshappliedtothesurroundingrockandforrockboltsatkeypositions.Thus,deformationcanbereducedconsiderablywherethesupportisloadeduniformly.Forourstudy,wedesignedareinforcedsupportschemewithacombinationofrockbolts,rebarnet,shotcrete,rebarjoistsandanchorcables.3.1.SupportmechanismThesupportmeasureshadthefollowingresults.(1)Couplingsupportbyrockboltsandcablespro-activelyprovidedconsiderablepreloadaswellasaxialandlateralresistancetothesurroundingrock.Thesupportingresistanceincreasedquicklyasthedeformationinthesurroundingrockdeveloped.(2)Reinforcementwassuppliedwhentheintensityofthesurroundingrockslightlydecreased.Therefore,thecompressionstrengthofthesurroundingrockwasmaximized.Asaresult,theconversionoftheloadingbodytothesupportbodyeffectivelycontrolledthedeformation.(3)Theanchorcablesprovideddeepsupport.Theroofreinforcementintrudedorextrudedtheserocksandthenformedacombinedbeam.Simultaneously,thearchspringofthereinforcementexpandedintothedeepercoalrip,whichloweredistheshallowfloorstress,reducedtheplasticdepthoftheripandintheendlimitedtheripdisplacementandfloorheave.3.2.SupportprinciplesCompressionminimizationrequirestherelaxationofhugeaccumulatedplasticenergywithinthesurroundingrock.Lithologytheoryandengineeringpracticesuggeststhatsurroundingrockdeformationwouldgraduallyincreaseafterexcavation.Giventhespeedofdeformation,deformationisgenerallydividedintoadeceleratingphase,anapproximatelylinearconstantphaseandanacceleratingphase.Whentherockfallsduringtheacceleratingphase,itsstructureisrebuilt,developsfissuresandlowersitsintensity.Inthiscase,theresistancecanbemaximizedduetodeformationconversion,whileitsabilitytosupplysupportdecreasessharply.Thus,itiscriticaltoselecttheoptimalreinforcementareasandtimberingtime.Duringcouplingsupport,advancedpracticesofanchorcablesalwaysleadstosnappingofsteelstrandsduetothelargedeformation;however,itshystereticsupportresultsintheseparationoflayersbetweendifferentsectionsofrockbolts.Therefore,anoptimalsecondarycouplingsupportisconsideredfollowingtheselistedprinciples.Inthecaseofprimaryrockboltsupportforlooseandbrokensurroundingrock,stressconcentrationzonescanbefixedbynumericalsimulationandreinforcedsupportofanchorcablescanbetimelyconstructed.3.3.NumericalsimulationofcouplingsupportAccordingtothecouplingsupportprinciplesofsoftrock,anchorcablesaremosteffectivewhentheyarefixedatkeypositionsinroofs.Inourstudy,weoptedfortheFLAC3Dsoftwarepackagetosimulatethedynamicstateofthefirstcouplingsupport(Fig.1,referstoacombinationofanchorgroutingandagroutinglayer),inordertofixtheoptimumpositionforthesecondarycouplingsupport.Fig.1.GeneralsituationofnumericalsimulationwithsoftwareFLAC3DThefinite-differencenumericalFLAC3Dpackageisdeemedtobesuitableforgeotechnicalengineering[10].UsingaLagrangianmethod,itisespeciallyusefulinsimulatingmaterialdeformationandtwists.Aswell,thissoftwareusesanexplicitalgorithmtoobtainatimestepsolutionofthekineticequationsofmodelsandthentrackstheirgradualfailuresandcollapse.TheMole-Coulombintensitylawwasselectedforthissimulation.Fig.2.PartiallyenlargedfigureofshearstressstateintheroofoftheroadwayFig.2presentsapartiallyenlargedfigureofournumericalsimulation.Itshowsthatstressconcentrationoccurredattheshouldersoftheroofoftheroadway,wherethemosturgentanchorcablesupportisneeded.Thesimulationalsoshoweditwascriticaltodesignasecondarycouplingsupport.Fig.3ashowsthatafterthefirstcouplingsupport,theplasticzonehasbecomecomparativelyenlargedintheroof,whereastheplasticzone,especiallyontheroofshoulders,hadsharplydecreasedafterthesecondarycoupling(Fig.3b).Theresultssuggestacorrectreinforcementofthesecondarycouplingwithanchorcables.Fig.3.Plasticzoneofsurroundingrockwithdifferentsupport4.AtypicalroadwaysupportinsoftseamsGiventheprinciplesenunciatedearlier,itisimportanttouseseveralkindsofsupportingschemesfortheroadwaysinseamswithsoftroofsandfloors.Torealizethis,wedesignedatargetedsupportforthe#2336transportationroadwayinthesecondShizuishancollieryinNingxia,China.Thetransportationlanewaywaslocatedthroughoutthelengthoftheseam,4.5mwideand3.0mhigh.Alongtheentirelanewaythecoalandroofaresoft,henceitwasdifficulttosupportalargespanlanewayinthistypeofseam.Onaveragetheseamwas7.79mthick,withamaximumof9.69mandaminimumof6.31m.Theupperpartoftheseamisbrightcoal(f=1.2),thelowerpartisdullcoal(f=0.8)andinbetweenarethreelayersofdirt0.12-0.70mthick.Theroofconsistsofsequentialkaolin(onaverage0.62mthick),carbonaceousshale(onaverage0.25mthick)andarenaceousshale(onaverage0.18mthick)fromthebottomup.Thefloorconsistsofsequentialclay(onaverage0.18mthick)andarenaceousshale(onaverage1.5mthick).4.1.FirstcouplingsupportofrockboltsThelengthofeachrockboltwasclosetotheloosecircleofitssurroundingrock.Accordingtoelastic–plastictheoryweestimatedthemostfrequentlyoccurringrangeofloosecircles.Thetransportationlanewaywasdesignedinarectangularfashionasrequiredanditsequivalentradiuswascalculatedtobe2.7musingEq.(2).〔2〕WhereBisthewidthofthelaneway;htheheightandr0theequivalentradius.Sincethelanewaywastemporaryunsupportedafterexcavation,itssupportcapacitywasnil.Thus,theradiusofthemaximumplasticcirclewithinthelanewaywas3.88m(60%ofthetrialdata),calculatedwithEq.(3).〔3〕WhereR0istheradiusofthemaximumplasticcircle;r0theradiusofthecavern;σ0=10.58MPaistheprimarygroundpressureanddependsontheweightstressoftheupperrock,C=2.0MPaisthelithologicalcohesionwithintheplasticcircleandu=35.0°istheinternalfrictionangleoftheplasticcircle.Thus,theloosecircleoftheroofandthesidewallswere1.98and2.13masdescribedbyEqs.(4)and(5),respectively.〔4〕〔5〕Thetheoreticaldataobtainedwasestimatedbasedontheassumptionthatthestressoftheprimaryrockwasunderhydrostaticpressure.Similarly,theloosecirclerangedfrom200to300cmandthereforethesurroundingrockwasclassifiedasaI-type.Length(L),interval(M)anddiameter(d)oftherockboltscanbedeterminedbyEqs.(6)-(8)[9].〔6〕〔7〕〔8〕WhereListhelengthoftherockbolt;Mtheintervalbetweentherockbolts;dthediameteroftherockbolt,N=1.2,i.e.thecoefficientofrockclassificationandWthespanofthelaneway,4.5m.Basedontheroadwayprojectinthemine,thelengthoftherockboltsintheroofwasdesignedtobe2.4mlong.Theboltsinthesidewallswereas2.0mlong,withboltspacingof800mmandarraypitch800mm.4.2.SecondarycouplingsupportofanchorcablesAccidentshappenwhenrockboltsandanchorcablesarenotsuccessfullycoupled.Inordertoachieveabettercouplingsupport,therockbolts,ontheonehand,shouldbeexactlyembeddedatthelanewayshoulderswherestressconcentrationoccurs;ontheotherhand,anchorcablesshouldbedesignedaccordingtothecouplingeffectofthetwosupportmethods.SimulationwascarriedoutwithparametersofanchorcablesassuggestedbyEqs.(9)and(10).〔9〕〔10〕WhereLa,la1andla3areoveralllength,exposurelengthandanchorlengthoftheanchorcablesrespectively,m;la2istheeffectivelengthoftheanchorcables,m;andatheequivalentwidthofthelaneway,m.Intheend,wedesignedthefinalsupportschemeemphasizingthecouplingeffectofrockboltsandanchorcables(Fig.4).ThecorrespondingsupportparametersareshowninTable1.Table1ParametersofacouplingsupportdesignforlanewayinatypicalsoftseamComponentComponenttypesLength(m)Interval(m)Arraypitch(m)RockboltsintheroofTwistedsteelΦRockboltsinthesidewallsTwistedsteelΦ1620.80.7AnchorcablesSteelstrainΦ2.4RebarjoistsRebarΦ14Length×width=2600mm×50mmFig.4.Couplingsupportdesignforlanewayinatypicalsoftseam5.FieldmonitoringofcouplingsupportThemainobjectofinsitumonitoringistorevealtheevolvementofthesurroundingrock,aswellasthestabilityandthereliabilityofthesupportsystem[11-15].Hence,theresultsofmonitoringprovidereferencesforlaterdesignsandconstruction.Asuitableschemewasthereforeimportantforinsitumonitoringandactedasavaliditycheckofthesupportscheme.5.1.MonitoringschemeSincethesurroundingrockinthiscollieryexertslowstrengthandissensitivetoexcavation,itisadifficultenvironmentfortheoperationofrockbolts.Themonitoringschememusttobeconstructedstrictlyaccordingitsdesigninordertoguaranteetheefficacyoftheconstructionandfieldmonitoring.Fig.5showsthefieldmonitoringsectionarrangementintermsofthecurrentsituationinthemine.Onsitemonitoringmainlyinvolvedthefollowingobjects:(1)Surfacedisplacementofthesurroundingrock(relativedisplacementofroofandfloor,relativedisplacementofsidewallsandroofsettlement);(2)Separationlayeroftheroof;(3)Stateofstressoftherockbolts.Inourstudy,wemonitoredsurfacedisplacementofthesurroundingrockwithaJSS30Aconvergencemeter,theseparationlayerdeepinthesurroundingrockwithaDDW-4multi-pointextensometerandthestateofstressoftherockboltswithaYJK4500Bdigitalstaticresistancestrainmeter.Monitoringdevelopedaccordingtothevariationintheseparameters.Monitoringfrequenciesofcircleconvergencedisplacementandroofsettlementweredeterminedbydisplacementvelocityanddistancefromtheexcavationface.Ingeneral,thisrequiredintensivemonitoring,especiallyatthebeginningoftheexcavationuntilthesurroundingrockstabilized.Monitoringwasconductedonceadaywhentheexcavationlengthwaslessthan50mandeverytwodayswhenexcavationextendedfurtherthan50m.Fig.5.FieldmonitoringsectionarrangementoflanewayinatypicalsoftseamInthemonitoringtimeframe,roofsettlementofthetransportationroadwayandtherelativeconvergenceofthesidewallswerecontrolledwithinlessthan120and110mm,respectively.5.2.ResultsoffieldmonitoringThemonitoringresultoftheobviousdeformationinthe#1roadwaysectionisshowninFig.6.Fig.6.Fieldmonitoringofacouplingsupportinatypical3SseamThemaximumsettlementoftheroofinthe#1sectionwas98mmanditsmaximumspeedis28mm/d(Fig.6a).Withinthemonitoringperiod,theminimumsettlementspeedoftheroofwasnomorethan0.1mm/dandaveraging1.02mm/d.Wefoundthatthemaximumrelativeconvergenceofthesidewallswas72mmandculminatedatlessthan0.08mm/d.Boththesettlementandconvergencestabilizedafter2months.Themaximumseparationoftherooflayerwas65mm,whichoccurredapproximatelyonday15anddecreasedgraduallyfromdeepsectionstoshallowones(Fig.6b).Theseparationlayerthereaftersettledataplateaudespitedifferentdepths.Everyanchorrodsharedacompressionofabout34kNafterday15(Fig.6c).Variationinloadingvelocityoftheanchorrodwasnomorethan0.4kN/d.Intheend,thedesignedcouplingsupporthadefficientlycontrolledthedeformationofthesurroundingrockinthissoftseam.6.ConclusionsOnthebasisofthedeformationofthesurroundingrockandlaneway,thetheoryofsupportinseamswithsoftroofsandfloorsandoursimulationandfieldmonitoringofanoptimalcouplingsupport,wedrawthefollowingconclusions.(1)Forroadwaysinseamswithsoftroofs,coalandfloors,deformationanditsrangeinthesurroundingrockislarge,roofsettlementisdistinctanddisplacementofthesidewallssevere.(2)Theproposedoptimumsupportisimportantforlanewaysupportinsoftseams.Itconsistsofafirstcouplingsupportwithrockboltsandsecondaryreinforcementwithanchorcables,whichweintroducedtimelyatkeypositions.Numericalsimulationimpliedthatstresswasconcentratedatroofshouldersoftheroadway,whichwereinthegreatestneedforurgentsupportofanchorcables.Theplasticzonedecreasedafterthesecondcouplingsupportwasinstalled,comparedtothesituationwithonlythefirstsupport.(3)Awellcoupledsupportofrockboltsandcablesisimportantforlanewaysupport,especiallyforlargespanroadwaysinsoftstrata.Theefficacyofanchorcablescanbemaximizedonlyiftheyarefixedatkeypositionsinroofsandfloorsandthereforecontrolthedeformationinordernottoendangerroadways.(4)Thefieldmonitoringshowsthattheoptimalcouplingsupportschemecanreducethedeformationofthesurroundingrockconsiderablyandguaranteethestabilizationoftheroadwayinsoftstrata.

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中文翻譯軟巖煤層大跨度巷道的變形研究及其支護(hù)技術(shù)摘要：我們研究了具有軟弱頂?shù)装宓南锏乐ёo(hù)工程方面的圍巖變形破壞機(jī)理，并觀(guān)測(cè)到了軟巖煤層中巷道的大跨度偏移。結(jié)果說(shuō)明，變形面積越大，頂板垮落和側(cè)向位移也就越明顯。我們考慮在軟弱頂?shù)装宓拿簩又胁捎缅^索耦合支護(hù)巷道，這樣錨索就可以固定在關(guān)鍵層中。與此同時(shí)，我們?cè)O(shè)計(jì)了一套針對(duì)中國(guó)寧夏石嘴山二礦軟巖煤層巷道支護(hù)的最正確方案?，F(xiàn)場(chǎng)監(jiān)測(cè)結(jié)果說(shuō)明，錨索耦合支護(hù)已經(jīng)到達(dá)了巷道穩(wěn)定性控制和最大限度地減少變形量的目的。關(guān)鍵詞：軟巖煤層；巷道變形；錨索耦合支護(hù)；現(xiàn)場(chǎng)監(jiān)測(cè)1引言煤炭為中國(guó)的經(jīng)濟(jì)增長(zhǎng)提供了大局部的能量。但世界各地對(duì)煤炭需求的不斷增加導(dǎo)致了在鄰近或在地球外表上能夠被經(jīng)濟(jì)地提取的煤炭資源的持續(xù)下降。因此，開(kāi)展采礦技術(shù)的趨勢(shì)應(yīng)該集中在深部開(kāi)采，這已是國(guó)際采礦業(yè)一個(gè)重要的研究領(lǐng)域[1,2]。尤其，在深部開(kāi)采技術(shù)中遇到的軟巖巷道，正在成為嚴(yán)重制約煤礦開(kāi)采的主要挑戰(zhàn)之一[3-7]。由具有軟弱頂?shù)装宓?/p>