Tunnelconstruction

隧道施工

項(xiàng)目三隧道施工方法Project3Tunnelconstructionmethod任務(wù)二隧道洞身開(kāi)挖方法——雙側(cè)壁導(dǎo)坑法Task2Tunnelexcavationmethod--bothsidedriftmethod學(xué)習(xí)目標(biāo)

Learningobjectives2知識(shí)目標(biāo)通過(guò)本任務(wù)的學(xué)習(xí)，學(xué)生應(yīng)掌握雙側(cè)壁導(dǎo)坑法施工工藝和施工要點(diǎn)；熟悉雙側(cè)壁導(dǎo)坑法的適用條件和優(yōu)缺點(diǎn)。KnowledgeobjectivesThroughthestudyofthistask,studentsshouldmastertheconstructiontechnologyandkeypointsofdoublesideheadingmethod;Befamiliarwiththeapplicableconditions,advantagesanddisadvantagesofbothsidedriftmethod.學(xué)習(xí)目標(biāo)

Learningobjectives3能力目標(biāo)通過(guò)本任務(wù)的學(xué)習(xí)，學(xué)生能應(yīng)按照工藝流程指導(dǎo)和檢查現(xiàn)場(chǎng)施工；具有對(duì)所從事職業(yè)的使命感和責(zé)任感。AbilityobjectivesThroughthestudyofthistask,studentscanguideandinspectthesiteconstructionaccordingtotheprocessflow;Havethesenseofmissionandresponsibilityfortheoccupation.一、工藝原理

Ⅰ.Processprinciple

雙側(cè)壁導(dǎo)坑法又稱(chēng)眼鏡工法，采用先開(kāi)挖隧道兩側(cè)導(dǎo)坑，及時(shí)施作導(dǎo)坑四周初期支護(hù)，必要時(shí)施作邊墻襯砌，然后再根據(jù)地質(zhì)條件、斷面大小，對(duì)剩余部分采用二臺(tái)階或三臺(tái)階開(kāi)挖的方法，其實(shí)質(zhì)是將大跨度的隧道變?yōu)槿齻€(gè)小跨度的隧道進(jìn)行開(kāi)挖。Thebothsidedriftmethodisalsocalledglassesmethod.Itisusedtoexcavatethetwosidesofthetunnel,andtimelysupportthesurroundingtunnel.Ifnecessary,theliningofthesidewallisapplied.Then,accordingtothegeologicalconditionsandthesizeofthesection,theexcavationmethodoftwostepsorthreestepsisadoptedfortheremainingpart.Theessenceistochangethelong-spantunnelintothreesmallspantunnelsforexcavation.二、施工流程

Ⅱ.Constructionprocess

第一步：先施工左側(cè)拱頂小導(dǎo)管并注漿，開(kāi)挖左側(cè)導(dǎo)洞上臺(tái)階，施作初期支護(hù)及側(cè)洞臨時(shí)支護(hù)；Step1:Constructionofsmallconduitonleftvaultandgrouting,excavatetheupperstepsofleftguidetunnel,andprovideinitialsupportandtemporarysupportforsidetunnel;

第二步：左側(cè)上臺(tái)階超前下臺(tái)階3-5m，開(kāi)挖下臺(tái)階土體，并施作初期支護(hù)及側(cè)洞臨時(shí)支護(hù)，閉合成環(huán)。Thesecondstep:Theleftupperstepis3-5maheadofthelowerstep,thesoilofthelowerstepisexcavated,andtheinitialsupportandtemporarysupportofthesidetunnelareimplementedtocloseintoaring.3~5m二、施工流程

Ⅱ.Constructionprocess

第三步：左側(cè)下臺(tái)階超前右側(cè)導(dǎo)洞10-15m，施做右側(cè)導(dǎo)洞拱頂小導(dǎo)管并注漿，開(kāi)挖右側(cè)導(dǎo)洞上臺(tái)階，施作初期支護(hù)及側(cè)洞臨時(shí)支護(hù)；開(kāi)挖和支護(hù)方法與左側(cè)上部導(dǎo)坑相同。

Thethirdstep:Theleftlowerstepis10-15maheadoftherightpilottunnel,therightpilottunnelvaultsmallconduitisconstructedandgroutingiscarriedout,therightpilottunnelisexcavatedtotheupperstep,andtheinitialsupportandtemporarysupportofthesidetunnelareconstructed;Theexcavationandsupportmethodisthesameastheleftupperheading.二、施工流程

Ⅱ.Constructionprocess第四步：右側(cè)上臺(tái)階超前下臺(tái)階3-5m，開(kāi)挖下臺(tái)階土體，并施作初期支護(hù)及側(cè)洞臨時(shí)支護(hù)，并閉合成環(huán)。

Step4:Therightupperstepis3-5Maheadofthelowerstep,thesoilofthelowerstepisexcavated,andtheinitialsupportandtemporarysupportofthesidetunnelareimplemented,andclosedintoaring.3~5m二、施工流程

Ⅱ.Constructionprocess

第五步：右側(cè)導(dǎo)洞下臺(tái)階超前中槽上臺(tái)階10-15m，施做中槽拱頂小導(dǎo)管并注漿，開(kāi)挖中槽上臺(tái)階，預(yù)留核心土，施作拱部初期支護(hù)；

Thefifthstep:Thelowerstepoftherightpilottunnelis10-15maheadoftheupperstepofthemiddlegroove,thesmallconduitonthevaultofthemiddlegrooveisconstructedandgrouted,theupperstepofthemiddlegrooveisexcavated,thecoresoilisreserved,andtheinitialsupportofthearchisconstructed;二、施工流程

Ⅱ.Constructionprocess第六步：中槽上臺(tái)階超前主洞中臺(tái)階3-5m，開(kāi)挖中臺(tái)階土體；Thesixthstep:Theupperstepofthemiddlegrooveis3-5Maheadofthemiddlestepofthemaintunnel,andthesoilofthemiddlestepisexcavated;3~5m6二、施工流程

Ⅱ.Constructionprocess第七步：中槽中臺(tái)階超前主洞下臺(tái)階3-5m，開(kāi)挖下臺(tái)階土體，施作仰拱初期支護(hù)，初期支護(hù)全斷面閉合。

Theseventhstep:Themiddlestepofthemiddlegrooveis3-5maheadofthelowerstepofthemaintunnel,thesoilofthelowerstepisexcavated,theinitialsupportoftheinvertedarchisimplemented,andthefullsectionoftheinitialsupportisclosed.3~5m二、施工流程

Ⅱ.Constructionprocess第八步：根據(jù)監(jiān)控量測(cè)情況分段拆除側(cè)導(dǎo)洞臨時(shí)支護(hù)，綁扎仰拱二襯鋼筋，澆筑仰拱二次襯砌及仰拱回填。Step8:Accordingtothemonitoringandmeasurement,thetemporarysupportofsidepilottunnelisremovedinsections,thesecondaryliningreinforcementofinvertisbound,thesecondaryliningofinvertispouredandtheinvertisbackfilled.仰拱填充二、施工流程

Ⅱ.Constructionprocess第九步：拱部、邊墻初期支護(hù)表面處理，鋪設(shè)防水層；Step9:Surfacetreatmentofarchandsidewallinitialsupport,layingwaterprooflayer;防水層waterproofbarrier初期支護(hù)initialsupport二、施工流程

Ⅱ.Constructionprocess第十步：模板臺(tái)車(chē)就位，全斷面二次襯砌混凝土澆筑。Step10:Theformworktrolleyisinplace,andthefullsectionsecondaryliningconcreteispoured.二、施工流程

Ⅱ.Constructionprocess問(wèn)題：二砌距掌子面距離應(yīng)當(dāng)是多少？Question:whatshouldbethedistancebetweensecondaryliningandthetunnelface?規(guī)范規(guī)定：二砌距掌子面距離:Ⅳ級(jí)軟弱圍巖不大于90米；Ⅴ級(jí)圍巖不大于70米。二、施工流程

Ⅱ.ConstructionprocessAccordingtothespecifications:Distancebetweensecondaryliningandtunnelface:GradeIVsoftsurroundingrockisnotmorethan90m；ThesurroundingrockofgradeVisnotmorethan70m.三、施工要點(diǎn)

Ⅲ.Keypointsofconstruction(1)圍巖開(kāi)挖應(yīng)盡量采用挖掘機(jī)和人工配合無(wú)爆破施工，局部需爆破施工時(shí)，宜弱爆破施工，以盡量減少對(duì)地層的擾動(dòng)。側(cè)壁導(dǎo)坑、中部開(kāi)挖應(yīng)采用短臺(tái)階，臺(tái)階長(zhǎng)度3~5m，必要時(shí)留核心土。(1)Theexcavationofsurroundingrockshouldbecarriedoutbyexcavatorsandmanualworkwithoutblastingasfaraspossible.Whenblastingisneededlocally,weakblastingshouldbeusedtominimizethedisturbancetothestratum.Shortstepsshallbeadoptedforsideheadingandmiddleexcavation,withalengthof3~5m,andcoresoilshallbereservedifnecessary.(2)開(kāi)挖應(yīng)嚴(yán)格按規(guī)范做好監(jiān)控量測(cè)工作，隨時(shí)掌握圍巖及支護(hù)的變形情況，以便及時(shí)修正支護(hù)參數(shù)，改變施工方法；同時(shí)，應(yīng)有較準(zhǔn)確的超前地質(zhì)預(yù)報(bào)。三、施工要點(diǎn)

Ⅲ.Keypointsofconstruction(2)Duringexcavation,themonitoringandmeasurementworkshouldbedoneinstrictaccordancewiththespecifications,andthedeformationofsurroundingrockandsupportshouldbegraspedatanytime,soastotimelycorrectthesupportparametersandchangetheconstructionmethod;Atthesametime,thereshouldbemoreaccurateadvancegeologicalprediction.(3)開(kāi)挖時(shí)的排水工作要認(rèn)真做好，在保證排水暢通的同時(shí)，重點(diǎn)要對(duì)兩側(cè)臨時(shí)排水溝鋪砌抹面，防止鋼支撐基底軟化。三、施工要點(diǎn)

Ⅲ.Keypointsofconstruction(3)Thedrainageworkduringexcavationshouldbedonecarefully.Whileensuringsmoothdrainage,thekeypointistopaveandplasterthetemporarydrainageditchesonbothsidestopreventthesofteningofsteelsupportbase.(4)側(cè)壁導(dǎo)坑開(kāi)挖后，應(yīng)及時(shí)施工初期支護(hù)并盡早形成封閉環(huán)；側(cè)壁導(dǎo)坑形狀應(yīng)近于橢圓形斷面，導(dǎo)坑跨度宜為整個(gè)隧道跨度的三分之一；左右導(dǎo)坑施工時(shí)，前后拉開(kāi)距離不宜小于15m；導(dǎo)坑與中間土體同時(shí)施工時(shí)，導(dǎo)坑應(yīng)超前30~50m。(4)Aftertheexcavationofthesideheading,theinitialsupportshouldbeconstructedintimeandtheclosedringshouldbeformedassoonaspossible;Theshapeofsidewallheadingshouldbeclosetoovalsection,andtheheadingspanshouldbeonethirdofthewholetunnelspan;Duringtheconstructionofleftandrightheading,thedistancebetweenfrontandbackshouldnotbelessthan15m;Whentheheadingandthemiddlesoilareconstructedatthesametime,theheadingshallbe30~50maheadoftheconstructiontime.三、施工要點(diǎn)

Ⅲ.Keypointsofconstruction(5)開(kāi)挖循環(huán)進(jìn)尺不宜大于初期支護(hù)鋼架設(shè)計(jì)間距。(5)Theexcavationcyclefootageshouldnotbegreaterthanthedesignspacingofinitialsupportsteelframe.≥15m三、施工要點(diǎn)

Ⅲ.Keypointsofconstruction四、優(yōu)缺點(diǎn)及適用條件

Ⅳ.Advantagesanddisadvantagesandapplicableconditions缺點(diǎn)：雙側(cè)壁導(dǎo)坑法開(kāi)挖斷面分塊多、擾動(dòng)大，初次支護(hù)全斷面閉合的時(shí)間長(zhǎng)，施工進(jìn)度較慢，成本較高。Disadvantages:Theexcavationsectionofdoublesideheadingmethodisdividedintomanyblocksanddisturbedgreatly,thetimeforthefirstsupporttoclosethewholesectionislong,theconstructionprogressisslowandthecostishigh.優(yōu)點(diǎn)：施工安全，每個(gè)分塊都是在開(kāi)挖后立即各自閉合的，在施工中間變形幾乎不發(fā)展。尤其在控制地表下沉方面，優(yōu)于其他施工方法?，F(xiàn)場(chǎng)實(shí)測(cè)表明，雙側(cè)壁導(dǎo)坑法所引起的地表沉陷僅為短臺(tái)階法的1/2。Advantages:Theconstructionissafe,eachblockisclosedimmediatelyafterexcavation,andthedeformationhardlydevelo