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1、第28卷第8期公路交通科技V01.28No.82011年8月JournalofHighwayandTransportationResearchandDevelopmentAug.201Idol:10.3969/j.issn.1002—0268.2011.08.002加筋碎石樁承載力計(jì)算趙明華,陳慶,張玲,馬繽輝(湖南大學(xué)巖土工程研究所,湖南長(zhǎng)沙410082)摘要:分析了加筋碎石樁復(fù)合地基的承栽機(jī)理。探討了加筋碎石樁復(fù)合地基的幾種破壞模式。在不同的破壞模式下根據(jù)極限平衡理論導(dǎo)出了加筋碎石樁單樁極限承栽力計(jì)算
2、公式。破壞模式l主要由格柵套筒抗拉強(qiáng)度控制,破壞模式2由加筋段樁體側(cè)摩阻力和非加筋段樁體鼓脹破壞前向上提供的端承力共同控制。實(shí)例計(jì)算表明,加筋碎石樁的承蛾力比普通碎石樁的承栽力有顯著提高,且加筋碎石樁的加筋深度與格柵抗拉強(qiáng)度之間有最優(yōu)組合。最合理地利用加筋格柵提高碎石樁承栽力,最后將加筋碎石樁應(yīng)用到了高速公路軟基處治中。關(guān)鏈詞:道路工程;加筋碎石樁;極限平衡;破壞模式;土工格柵;極限承栽力中圖分類號(hào):U416.1;TU473.1文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1002一0268(2011)08—0007—06Ca
3、lculationofBearingCapacityofGeosynthetic-encasedStoneColumnsZHAOMinghua,CHENQing,ZHANGLing,MABinhui(GeotechnicalEngineeringInstitute,HunanUniversity,ChangshaHunan410082,China)Abstract:Thebearingmechanismofcompositefoundationofgeosynthetie-encasedstonecolu
4、mnswasanalyzed,andseveralkindsoffailuremodeofthecompositefoundationwereinvestigated.Indifferentfailuremodes,accordingtothelimitequilibriumtheory,acalculationformulaoftheultimatebearingcapacityofsinglegeosynthetic-encasedstonecolumnwagproposed.Failuremode1
5、ismainlycontrolledbythetensilestrengthofgeogridsleeve,andfailuremode2iscontrolledbythepile-lateralfrictionofgeosynthetie-encasedstonecolumnandtheendbearingcapacityofcommonstonecolumnbeforethedamageofswellingdeformation.Theexampleofcalculationindicatesthat
6、the(1)bearingcapacityofgeosynthetic-encasedstonecolumnhassignificantlyimprovedthanthatofcommonstonecolumn;(2)thereinforcingdepthofgeoaynthetic-encasedstonecolumnandthetensilestrengthofgeogridsleevehaveabestcombinationforthemoatrationalusingofgeogridtoimpr
7、ovethebearingcapacityofthestonecolumn.Atlast,thegeosynthetic—encasedstonecolumnswereappliedtotreatmentofweaksubgradeofexpressway.Keywords:roadengineering;geosynthetic—encasedstonecolumn;limitequilibrium;failuremode;geogrid;bearingcapacity0引言碎石樁復(fù)合地基技術(shù)由于其具有
8、提高地基承載力、加速軟基固結(jié)沉降等作用而在軟土地基加固中得到廣泛應(yīng)用。但碎石樁承載作用的發(fā)揮需要樁周土體向其提供一定的側(cè)向約束力。豎向荷載作用下,若樁周土體不能提供足夠的側(cè)向約束力,碎石樁就會(huì)向側(cè)向發(fā)生鼓脹破壞。已有研究表明[1。21:碎石樁的側(cè)向鼓脹變形易發(fā)生在距樁頂l一3倍樁徑深度范圍內(nèi)。收稿日期:2010—09—05基金項(xiàng)目:國(guó)家高技術(shù)研究發(fā)展計(jì)劃(/k六--"計(jì)劃)項(xiàng)目(2006AAIlZl04)作者簡(jiǎn)介:趙明華(19