采礦學(xué)王莊煤礦論文設(shè)計

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)測數(shù)據(jù)可作為修改、完善錨桿支護(hù)初始設(shè)計數(shù)據(jù)的依據(jù)之一。頂板離層指示儀實際上是兩點巷道圍巖位移計。在頂板鉆孔中布置兩個測點，一個在圍巖深部穩(wěn)定處，一個在錨桿端部圍巖中。離層值就是圍巖中兩測點之間以及錨桿端部圍巖與巷道頂板外表間的相對位移值，并可直觀顯示出相對位移值(離層量)的大小?！?〕位移量監(jiān)測，利用多點位移計來完成巖層深部位移監(jiān)測，多點位移計是監(jiān)測巷道在掘進(jìn)和受采動影響的整個效勞期間深部圍巖變形隨時間變化情況的一種儀器。安設(shè)多點位移計的目的：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)變是否超過極限應(yīng)變量；為修改錨桿支護(hù)設(shè)計提供依據(jù)。

4煤巷錨桿支護(hù)技術(shù)在王莊煤礦的應(yīng)用4.1王莊煤礦簡介潞安集團王莊煤礦設(shè)計生產(chǎn)能力為4.0Mt/a，立井單水平開拓，準(zhǔn)備方式為帶區(qū)，煤層開采方法為大采上下位放頂煤工藝，主采煤層為3號煤層，其中運輸大巷和輔助運輸大巷布置與巖層中，回風(fēng)大巷布置于煤層中，分帶斜巷長度到達(dá)了2700m，煤巷錨桿支護(hù)技術(shù)對于礦井巷道支護(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)王莊煤礦膠帶運輸大巷、輔助運輸大巷及回風(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)，其中膠帶運輸大巷和輔助運輸大巷為半圓拱形斷面，膠帶運輸大巷布置于巖層，設(shè)計掘進(jìn)斷面積為19.8m2，混凝土噴射厚度100mm，樹脂錨固劑加固，錨桿排列方式為三花式，錨桿間距800mm，示意見圖4-1；圖4-1膠帶運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，樹脂錨固劑加固，錨桿長度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)行錨索補強。錨桿直徑Φ20mm，長度2.2m，左旋無縱筋螺紋鋼錨桿〔高強度〕，樹脂加長錨固，破斷力230kN，錨桿間排距800mm；WX220/3.0型鋼帶寬為220mm，長4250mm，厚3mm；采用菱形金屬網(wǎng)護(hù)頂；單根鋼絞線錨索，長6.3m，首采面安設(shè)在巷道頂脊線處，間距1.6m。托盤：采用拱形高強度托盤，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50×50mm、5.5×1.1m。〔2〕巷幫支護(hù)錨桿直徑Φ20mm，長度2.2m，左旋無縱筋螺紋鋼錨桿〔高強度〕，樹脂加長錨固，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，聽取各方技術(shù)人員的意見制定?王莊煤礦錨桿支護(hù)技術(shù)標(biāo)準(zhǔn)?，在地質(zhì)評估、支護(hù)設(shè)計、支護(hù)材料的選用、施工行為標(biāo)準(zhǔn)、施工質(zhì)量驗收標(biāo)準(zhǔn)、數(shù)據(jù)監(jiān)測監(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。〔2〕管理保障，加強施工作業(yè)機械工具及材料的管理，組成檢查小組，定期對井下采掘巷道進(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)問題或危險征兆，及時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。〔3〕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)專業(yè)知識，提高技術(shù)水平。〔4〕礦壓監(jiān)測預(yù)警機制，建立可靠完善的礦壓監(jiān)測監(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)測站，實時監(jiān)測，及時反響監(jiān)測結(jié)果，并對檢測結(jié)果進(jìn)行分析、處理，與對巷道平安提供監(jiān)測預(yù)防作用。

5煤巷錨桿支護(hù)技術(shù)的改良途徑5.1開展現(xiàn)狀伴隨著技術(shù)開展，需求增加，開采深度也不斷增加，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，伴之而來的是地質(zhì)條件的復(fù)雜和進(jìn)一步的惡化，這就對巷道支護(hù)技術(shù)提出了更高的要求。同時，采煤機械的自動化與采煤方法的高效化開展，綜采放頂煤、厚煤層一次采全高開采技術(shù)的快速開展和大面積應(yīng)用，對煤巷錨桿支護(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越大，支護(hù)難度顯著加大，這無疑需要巷道支護(hù)技術(shù)作出更好更強的改變。5.2煤巷錨桿支護(hù)技術(shù)改良途徑〔1〕增強錨桿的初錨力，跟據(jù)相關(guān)資料說明，國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。初錨力相對過小，降低了對圍巖的支護(hù)效果，不利于維持巷道圍巖的長期穩(wěn)定?！?〕加強煤層巷道巷幫支護(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)生松動掉落，加大懸頂面積，易導(dǎo)致頂板破損，甚至冒落。因此，加強對巷道煤幫的支護(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)新型高強度錨桿也是增強煤巷錨桿支護(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，采用小孔徑錨索對其進(jìn)行支護(hù)，可有效的對頂板進(jìn)行加固支護(hù)，保持頂板巖層的長期穩(wěn)定?！?〕推廣以錨桿支護(hù)為主的聯(lián)合支護(hù)形式，隨著開采深度的加深，動壓影響對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)已無法完全滿足巷道支護(hù)要求，所以對于地壓大的不穩(wěn)定的圍巖，聯(lián)合支護(hù)必不可少。〔6〕加強頂板動態(tài)檢測監(jiān)控，確保煤巷錨桿支護(hù)平安。根據(jù)國外經(jīng)驗要制定相應(yīng)的檢測監(jiān)控標(biāo)準(zhǔn)，對錨桿支護(hù)狀態(tài)下的巷道頂板進(jìn)行準(zhǔn)確的實時監(jiān)控，及時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態(tài)，發(fā)現(xiàn)異常及時采取加強支護(hù)措施，防止危險發(fā)生；另一方面統(tǒng)計反響信息，依據(jù)數(shù)據(jù)修改設(shè)計參數(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)是煤炭開采過程中的一項重要技術(shù)，具備大量的理論依據(jù)和實踐經(jīng)驗，經(jīng)過50多年的開展逐步成熟。錨桿支護(hù)技術(shù)為一種主動支護(hù)形式，具有支護(hù)速度快、支護(hù)效果好、材料本錢低、工作人員勞強度小等優(yōu)點，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)帶來有效的平安支護(hù)保障和顯著的經(jīng)濟效益。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)過多年開展實踐證明，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)的開展方向。目前，隨著礦井開采深度增加，圍巖條件變得愈發(fā)復(fù)雜，支護(hù)也相對困難，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,郭勵生,勾攀峰.煤巷錨桿支護(hù)[M].徐州:中國礦業(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：中國建筑工業(yè)出版社,2003.[6]何滿朝,袁和生,靖洪文.中國煤炭錨桿支護(hù)理論與實踐[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.預(yù)應(yīng)力在錨桿支護(hù)中的作用[J].煤炭學(xué)報,2007,32(7):673-678.[10]康紅普.軟巖回采巷道錨桿支護(hù)技術(shù)的開展[A].軟巖工程專業(yè)委員會第二屆學(xué)術(shù)會議論文集[C].北京:1999.[11]康紅普.高強度錨桿支護(hù)技術(shù)的開展與應(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:中國礦業(yè)大學(xué)出版社,1999.[13]鞠文君,王澤進(jìn).測力錨桿研制與應(yīng)用技術(shù)[J].煤礦開采,1997,增刊:54-57.[14]鞠文君.全長錨固錨桿工況監(jiān)測方法[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〞referstoroadwaysinmineswithsoftroofs,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理，并觀測到了軟巖煤層中巷道的大跨度偏移。結(jié)果說明，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，我們設(shè)計了一套針對中國寧夏石嘴山二礦軟巖煤層巷道支護(hù)的最正確方案?，F(xiàn)場監(jiān)測結(jié)果說明，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)場監(jiān)測1引言煤炭為中國的經(jīng)濟增長提供了大局部的能量。但世界各地對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)濟地提取的煤炭資源的持續(xù)下降。因此，開展采礦技術(shù)的趨勢應(yīng)該集中在深部開采，這已是國際采礦業(yè)一個重要的研究領(lǐng)域[1,2]。尤其，在深部開采技術(shù)中遇到的軟巖巷道，正在成為嚴(yán)重制約煤礦開采的主要挑戰(zhàn)之一[3-7]。由具有軟弱頂?shù)装宓?/p>