文档摘要:中等断面隧道受施工范围限制易导致爆破难度大,循环进尺短,超欠挖问题严重,长进尺开挖和超欠挖控制是降本增效的有效途径.基于某中等断面隧道工程设计了长进尺直孔掏槽爆破方案,进行了40个循环的爆破开挖现场试验,结果表明:(1)按照爆破手册设计中等断面隧道开挖爆破参数,往往大块率高,掌子面不平整,适当增加直孔掏槽孔单孔装药量(现场试验掏槽药量占比由12.8%增至18.1%),可获得较好的爆破效果;(2)在初步设计参数基础上调整了中等断面隧道周边孔单孔装药量,线装药密度最终确定为0.27kg/m,轮廓成形效果好,半孔率达90%以上,现场40个爆破循环超挖平均值为18.6cm,分析可知超挖量主要由轮廓线处留置错台造成,在超挖控制方面,除了周边孔参数的合理设计外,应在钻孔施工过程中尽可能减小错台宽度,从而降低超挖;(3)直孔掏槽方案能很好地匹配凿岩台车钻孔施工,实现机械化长进尺爆破开挖,但超欠挖精细控制和爆破施工成本控制是重难点问题,需从钻孔人员操作技术和现场施工管理模式方面进行优化提升.研究成果可为中等断面隧道机械化钻爆施工、长进尺爆破开挖与超欠挖精细控制设计和施工提供参考依据.
Abstract:Duetothelimitationsinconstructionscope,blastingamedium-sectiontunnelischallengingasitof-tenresultsinshortcircularfootageandsignificantoverandunderexcavation.Toreducecostsandincreaseefficien-cy,itisessentialtofocusonlongfootageexcavationandfinecontrolofoverandunderexcavation.Inthisstudy,astraightholecuttingblastingschemewasdesignedforamediumsectiontunnelprojectand40cyclesofblastingexca-vationfieldtestswereconducted.Theresultsrevealedthatwhendesigningthelongfootageblastingparametersforamediumsectiontunnelbasedontheblastingdesignmanual,issuessuchashighblockrateandunevenfacefrequent-lyarise.However,byappropriatelyincreasingthechargeofthecutpart(theproportionofchargeofthecutpartin-creasedfrom12.8%to18.1%inourfieldtest),betterblastingeffectswereachieved.Additionally,byreducingthechargeamountofperipheralholesandadjustingtheirdistancefromeachother,smoothblastingeffectwaseffectivelyensured.Duringthefieldtest,adjustmentsweremadetothechargeamountofperipheralholesbasedonpreliminarydesignforblastingparameters.Thisresultedingoodcontourformingeffectswithahalf-holerateexceeding90%.However,anaverageovercuttingvalueof18.6cmwasobservedacrossall40excavationsectionsduringtheblastingcycle.Themaincauseforthisovercuttingwasidentifiedasplatformirregularitiesalongthecontourline.Toaddressthisissue,itisnecessarynotonlytoreduceexternaldrillinganglesbutalsocontrolplatformwidthalongsidereasona-bleparameterdesignsforsurroundingholes.Thestraightholecuttingschemeprovedcompatiblewiththree-armrockdrillingtruckconstructionmethodswhileenablingmechanizedlong-shotblastingexcavations.Nevertheless,precisecontroloverovercuttingandundercuttingremainschallengingalongwithcostmanagementduringblastconstruction.Itisnecessarytooptimizeandimprovetheoperationtechnologyofdrillingpersonnelandthemanagementmodeofsiteconstruction.
作者:龚伟毅 姚颖康 杜宇翔 Author:GONGWei-yi YAOYing-kang DUYu-xiang
作者单位:中铁十二局集团第一工程有限公司,西安710038江汉大学精细爆破国家重点实验室,武汉430056;江汉大学湖北(武汉)爆炸与爆破技术研究院,武汉430056
刊名:爆破 ISTICPKU
Journal:Blasting
年,卷(期):2024, 41(2)
分类号:TU375.1
关键词:中等断面隧道 直孔掏槽 长进尺开挖 超欠挖控制 精细爆破
Keywords:mediumsectiontunnel burncut longfootageexcavation overandunderexcavationcontrol pre-ciseblasting
机标分类号:U45TD235TU751.9
在线出版日期:2024年7月1日
基金项目:中等断面隧道长进尺直孔掏槽爆破开挖与超欠挖控制现场试验[
期刊论文] 爆破--2024, 41(2)龚伟毅 姚颖康 杜宇翔中等断面隧道受施工范围限制易导致爆破难度大,循环进尺短,超欠挖问题严重,长进尺开挖和超欠挖控制是降本增效的有效途径.基于某中等断面隧道工程设计了长进尺直孔掏槽爆破方案,进行了40个循环的爆破开挖现场试验,结果...参考文献和引证文献
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关键词:中等断面隧道,直孔掏槽,长进尺开挖,超欠挖控制,精细爆破,
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