2023年第3期工程勘察GeotechnicalInvestigation&Surveying7深厚砂层桩端后注浆灌注桩现场试验研究鹿存亮(上海勘察设计研究院(集团)有限公司,上海200093)摘要:深厚砂层中钻孔灌注桩施工存在泥皮厚、桩端沉渣难控制等问题。本文以中原某项目为例,对钻孔灌注桩采用桩端后注浆工艺进行加强处理,并在现场进行了一系列竖向抗压静载荷试验和抗拔试验。试验表明:在深厚密实砂层中采用桩端后注浆工艺,再满足一定量的注浆量后可同时达到加固桩端和桩侧的效果,有效提高桩端阻力和桩侧摩阻力;竖向抗压承载力极限值综合提高系数可达3.5,抗拔承载力极限值提高系数可达2.0;桩端沉降大小与注浆量密切相关。本研究可为后续类似深厚砂层钻孔灌注桩桩端后注浆的设计提供参考和借鉴。关键词:深厚砂层;桩端后注浆;现场载荷试验;双套管;沉降杆;钢筋应力计中图分类号:TU473文献标识码:AFieldtestofpost-groutingboredpileinthicksandlayerLuCunliang(ShanghaiGeotechnicalInvestigations&DesignInstituteCo.,Ltd.,Shanghai200093,China)Abstract:Therearesomeproblemsintheboredpileconstructionindeepsandlayer,suchasthickslurrycoatingandbottomsedimentcontrol.Inthispaper,acasestudyofaboredpilesimprovedbypost-groutingatthepilebottomiscarriedout.Aseriesofverticalcompressionandpull-outstaticloadtestarecarriedoutonsite.Thetestresultsshowthatthepileendandpilesidecanbestrengthenedsimultaneouslyusingpost-groutingtechniqueinthedeepanddensesandlayer,andthepileshaftfrictionandpileendresistancecanbeeffectivelyimprovedafteracertainamountofgrouting;thecomprehensiveincreasecoefficientoftheultimatevalueoftheverticalcompressivebearingcapacitycanreach3.5,andtheincreasecoefficientoftheultimatevalueoftheupliftbearingcapacitycanreach2.0;thesettlementofpileiscloselyrelatedtotheamountofgrouting.Thisstudycanprovidereferenceforthedesignofpost-groutingatthepilebottomofboredpileinsimilargeologicalconditions.Keywords:thicksandlayer;post-groutingatboredpilebottom;sitestaticloadtest;doubletubing;settlementrod;reinforcementstressmeter收稿日期:2022-04-05;修订日期:2022-07-06作者简介:鹿存亮(1984-),男(汉族),江苏徐州人,硕士,高级工程师.0引言在深厚砂层中,灌注桩在施工过程中容易产生桩侧泥皮厚、桩端沉渣大及持...
