浅埋小净距偏压隧道合理开挖顺序探讨.pdf

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1、第10卷第5期铁道科学与工程学报V0l

2、1ONO．52013年10月JOURNALOFRAIL＼／＼『AYSCIENCEANDENGINEERINGOct。2013浅埋小净距偏压隧道合理开挖顺序探讨张运良。扶晓康，刘海林，郑阳焱(中南大学土木工程学院，湖南长沙410075)摘要：运用ANSYS有限元程序，研究浅埋偏压小净距隧道在不同的偏压角度、间距、埋深条件下，先开挖深埋侧和先开挖浅埋侧2种不同的开挖顺序下的受力和变形特性，对比分析了围岩最大拉应力、围岩洞周最大位移、中岩柱水平位移和竖向应力。研究结果表明：随着角度的增加，先开挖深埋侧较先开挖浅埋侧隧道及中岩柱更加安全；当间

3、距小于0．5倍洞径时，先开挖深埋侧较先开挖浅埋侧安全；当间距大于0．75倍洞径时，先开挖浅埋侧对于隧道受力更加有利；当埋深在1倍洞径以下，先开挖深埋侧隧道整体稳定性及受力更加安全，当埋深大于1．5倍洞径时，先开挖浅埋侧隧道受力更加安全。关键词：小净距；偏压隧道；浅埋；拉应力；中岩柱中图分类号：U459．2文献标志码：A文章编号：1672—7029(2013)05—0057—07Studyonthereasonableexcavationsequenceofshallow—embeddedbiastunnelswithsmalIcleardistanceZHANGYunlia

4、ng，FUXiaokang，LIUHailin，ZHENGYangyan(SchoolofCivilEngineering，CentralSouthUniversity，Changsha410075，China)Abstract：Basedontheconditionsofdifferentbiasangles，differentcleardistancesanddifferentburialdepths，themechanicalanddeformationcharacteristicsoftunnelswerestudiedundertwodifferentexcava

5、tionsequenceswiththeANAYSfiniteelementprogram．Acomparativeanalysisofthemaximumtensilestress，themaximumdisplacementaroundthetunnel，thehorizontaldisplacementandverticalstressofthemiddlerockpillarwerecar-fledout．Theresultsshowthatthesurroundingrockandmiddlerockpillararesaferwiththedeepsideoft

6、unnelexcavatedearlierthanthatwithshallowoneexcavatedfirstwiththeincreaseoftheunsymmetricalloadingangle．Itissafertoexcavatethedeepsideoftunnelearlierwhenthespacingislessthan0．5timesofthediameterofthetunne1．However．itiSadvantageoustothestressofthetunneliftheshallowsideoftunnelisexcavatedfirs

7、twhenthespacingexceeds0．75timesofthediameterofthetunne1．Moreover，thestabilityandstressofthetunnelaresaferifthedeepsideoftunneliSexcavatedearlierwhiletheburialdepthiSlessthan1timesofthediameterofthetunne1．WhereasexcavatingtheshallowsideoftunnelearlieriSsaferwhentheburialdepthexceeds1．5times

8、ofthediameterofthetunne1．Keywords：smallcleardistance；biastunnel；shallow—embedded；tensilestress；middlerockpillar近年来，对于浅埋偏压小净距隧道合理开挖顺塑性区较小，右洞拱顶塑性区较小，左洞拱顶不会出序，众多学者进行了一些研究工作，如：杨小礼等。现围岩拉裂区；李星平等通过对两车道偏压隧道通过对浅埋小净距双洞六车道偏压公路隧道不同开施工数值模拟得到先开挖深埋侧能避免出现较危险挖顺序施工数值模拟得到先开挖深埋一侧