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1、JournalofEngineeringGeology工程地質(zhì)學(xué)報(bào)1004-9665/2010/18(5)一0589—07關(guān)于脆性巖體巖爆成因的理論分析伍法權(quán)①伍劫②祁生文①(①中國(guó)科學(xué)院工程地質(zhì)力學(xué)重點(diǎn)實(shí)驗(yàn)室中國(guó)科學(xué)院地質(zhì)與地球物理研究所北京100029)(②中國(guó)地質(zhì)大學(xué)(武漢)武漢430074)摘要大型工程開(kāi)挖中,高地應(yīng)力環(huán)境下高儲(chǔ)能脆性巖體通常會(huì)通過(guò)脆性破裂快速釋放應(yīng)變能,產(chǎn)生巖爆。針對(duì)這類(lèi)巖爆現(xiàn)象進(jìn)行了一系列理論探討,認(rèn)為:(1)開(kāi)挖條件下脆性巖體的巖爆破壞主要為張破裂或者張剪性破裂,破裂角一般較小,呈薄片狀或刀口狀。
2、筆者認(rèn)為開(kāi)挖產(chǎn)生次生張應(yīng)力和壓剪應(yīng)力條件下微裂紋裂尖出現(xiàn)張應(yīng)力是可能的,因此采用格里菲斯強(qiáng)度理論研究開(kāi)挖巖體破裂是有效的;(2)以格里菲斯強(qiáng)度理論為基礎(chǔ),分析了巖體在二維和三維情形下的巖爆破裂應(yīng)力判據(jù)和破裂角,指出在有張應(yīng)力的條件下,巖體的剪破裂角會(huì)減小,直至為零,這就解釋了開(kāi)挖面附近薄片狀、刀口狀破裂現(xiàn)象的原因;(3)分析了脆性巖體巖爆破裂的能量過(guò)程,指出張性破裂所耗能量較小,而張剪性和壓剪性破裂耗能較高。認(rèn)為巖爆破裂消耗的能量主要轉(zhuǎn)化為新生裂紋的表面能和破裂碎片的動(dòng)能,并指出表面能所占比例較動(dòng)能為小。由此解釋了脆性巖體巖爆
3、破壞以動(dòng)力效應(yīng)為主的特征;(4)本文理論分析成果的工程應(yīng)用價(jià)值在于:可以預(yù)示開(kāi)挖脆性巖體破裂部位、破裂方式和破裂范圍;提出巖爆破裂的張性應(yīng)力控制依據(jù)。關(guān)鍵詞巖爆破裂判據(jù)破裂角動(dòng)能中圖分類(lèi)號(hào):P642文獻(xiàn)標(biāo)識(shí)碼:ATHEoRETICALANALYSISONMECHANISMoFRoCKBURSToFBRIT.TLERoCKMASSWUFaquan①WUJie②QISbengwen④(①研LaboratoryofEngineeringGeomechanics,InstituteofGeologyandGeophysics,Chin
4、eseAcademyofSciences,Belling100029)(②ChinaUniversityofGeosciences,Wuhan430074)AbstractBrittlerockmassgenerallyreserveshighstrainenergyunderhighgrounds~esscondition.Asitisexca-vated,rockburstwilltakeplace,asarapidreleaseofthereservedstrainenergy.Thispaperexploresthem
5、echanismofrockburstandobtainedthefollowingpoints:(1)Phenomenahaveshownthatrockburstispossiblyakindoften-sileandtension—shearfailureandthefailureangleisrelativelysmal1.Itispointedoutthatexcavationcaninducetensionalstressstateinrockmass.(2)Twoandthreedimensionalcriter
6、iaforrockburstbasedonGrifiththeoryhavebeenproposed,andthetheoreticalanalysishasconfirmedthatthefailureanglewillbereducedwiththeOccur—renceoftensionalstressstate,tillzerowhilepuretensionalstate.(3)Theenergyanalysishasshownthattheenergyconsumedforpuretensionalfailurei
7、srelativelylessthanthatfortension'shearfailureofcompressive—shearfailure.Andthestrainenergydissipatedinfailurewillmainlytransferredintosurfaceenergyfornewlycreatedcracksand收稿日期:2010—09—01;收到修改稿日期:2010—09—21.基金項(xiàng)目:國(guó)家自然科學(xué)基金重點(diǎn)項(xiàng)目(41030749)、鐵道部重大科技攻關(guān)項(xiàng)目(2009G005.A)資助第一作者簡(jiǎn)介
8、:伍法權(quán),工程地質(zhì)專(zhuān)業(yè).Email:wufaquan@mail.igcas.a(chǎn)c.cn590JournalofEngineeringGeology工程地質(zhì)學(xué)報(bào)2010thekineticenergyofthefailurepiecesofrock.Theoreticalana