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1、浙江大學(xué)碩士學(xué)位論文圓形隧道圍巖應(yīng)力與位移的數(shù)值模擬與分析姓名:張仙義申請(qǐng)學(xué)位級(jí)別:碩士專(zhuān)業(yè):巖土工程指導(dǎo)教師:謝康和20070501圓形隧道圍巖應(yīng)力與位移的數(shù)值模擬與分析摘要隧道開(kāi)挖前巖體處于初始應(yīng)力狀態(tài)。開(kāi)挖后引起圍巖應(yīng)力的重分布,同時(shí)圍巖將產(chǎn)生向隧道內(nèi)的位移,形成新的應(yīng)力場(chǎng),稱(chēng)之為圍巖的二次應(yīng)力狀態(tài)。如果二次應(yīng)力狀態(tài)不能使圍巖保持長(zhǎng)期穩(wěn)定,就必須設(shè)置支護(hù)結(jié)構(gòu),從隧道內(nèi)部對(duì)圍巖施加約束,控制圍巖變形,改善圍巖的應(yīng)力狀態(tài),促使其穩(wěn)定,這就是三次應(yīng)力狀態(tài)。對(duì)隧道圍巖各階段應(yīng)力位移狀態(tài)的準(zhǔn)確分析和把握,顯然是進(jìn)行
2、合理可靠的隧道工程設(shè)計(jì)和施工的關(guān)鍵。本文在現(xiàn)有研究基礎(chǔ)上,運(yùn)用彈塑性理論和大型三維巖土數(shù)值軟件FLAC3D,對(duì)圓形隧道從開(kāi)挖前直到開(kāi)挖支護(hù)后圍巖各個(gè)階段的應(yīng)力位移狀態(tài)等進(jìn)行了較為系統(tǒng)的總結(jié)和分析。主要工作包括:1.簡(jiǎn)要介紹了FLAC3D的基本原理和主要特點(diǎn);2.在假定初始應(yīng)力等向(即側(cè)壓力系數(shù)A=1)條件下歸納、總結(jié)和推導(dǎo)了二次彈性圍巖應(yīng)力位移狀態(tài)、二次塑性圍巖應(yīng)力位移狀態(tài)以及三次塑性圍巖應(yīng)力位移狀態(tài)的理論解析式;3.利用FLAC3D模擬分析了圓形隧道各個(gè)階段圍巖的應(yīng)力位移狀態(tài),并與理論解進(jìn)行了比較;4.對(duì)圓形
3、隧道圍巖應(yīng)力和位移狀態(tài)的分布特征和影響因素以及支護(hù)對(duì)圍巖穩(wěn)定性的影響進(jìn)行了分析,闡明了圍巖徑向正應(yīng)力、切向正應(yīng)力、徑向位移等在不同條件下的分布和變化規(guī)律;5.通過(guò)數(shù)值計(jì)算比較分析了圍巖剪脹性對(duì)圓形隧道圍巖應(yīng)力和位移的影響,以及初始應(yīng)力不等向(即側(cè)壓力系數(shù)五≠1)對(duì)圍巖塑性區(qū)范圍和形狀的影響。本文的研究對(duì)隧道工程的設(shè)計(jì)和施工有指導(dǎo)作用和參考價(jià)值。關(guān)鍵詞:圓形隧道,應(yīng)力,位移,解析式,F(xiàn)LAC3D,數(shù)值模擬NumericalSimulationandAnalysisoftheStressandDisplacemen
4、tofCircularTunnelinRockAbstractBeforeexcavatingatunnelinrock,therockis砒initialstressstate.Excavationcausestheredistributionofstressandthedisplacementtowardsthecentreofthetunnelinrock,andthusformsanewstressfield,knownasthesecondrockStressstate.Iftherockalthes
5、econdstressstatecannotmaintainlong-termstability,Wemustsetupretainingstructuresinordertoimposetheconstraintsonthesurroundingrockwithinthetunnel,controltherockdeformation,improvethestressstateandmaketherockstable,whichisknownasthethirdstressstate.Obviously,it
6、isthekeytoareasonableandreliabledesignandconstructionofthetunnelinrocktOfindandknowthestressanddisplacementinthesurroundingrockwithinthetunnelateachconstructionstage.Inthisthesis,asystematicalstudywasmade011thedistributionsofthestressanddisplacementinthesurr
7、oundingrockwithinthetunnelatdifferentconslructionstagebyusingelasto-plastictheoryandFLAC3DonthebasisoftherelevantworkSOfaravailable.n圮maincontributionsofthethesisinclude:1.哪垃basicprinciplesandmainfeaturesofFLAC3Dwereintroducedbriefly.2.Based011theassumptiont
8、hattheinitialstressinrockisisotropic,someanalyticalexpressionsweresummarizedandderivedforthedistributionsofstressanddisplacementintherockofcirculartunnelatthesecondelasticandplasticstatesandatth