钻孔扩底灌注桩承载性状分析  

Analysis of Bearing Characteristic of Drilling Expanded Bottom Cast-in-situ Piles

作　　者：郑金伙 Zheng Jinhuo(Fujian Provincial Institute Design and Research Co.,Ltd.,Fuzhou 350001,Fujian,China)

机构地区：[1]福建省建筑设计研究院有限公司,福建福州350001

出　　处：《岩土工程技术》2023年第1期83-88,共6页Geotechnical Engineering Technique

摘　　要：为研究钻孔扩底灌注桩承载性状,对2根不同扩大头形状的钻孔扩底灌注桩和1根等直径钻孔灌注桩进行单桩竖向抗压静载试验,并对其中的扩底桩同步进行桩身应力测试。测试及数据分析结果表明:沉渣及土层软化对扩底桩承载力影响较为敏感,除了直接影响桩端阻力发挥外,还会产生桩侧摩阻力弱化效应;扩大头形状影响孔底清渣效果,桩底高压注浆可消除或部分消除沉渣影响;不同试验桩的同一土层桩侧摩阻力发挥值为非定值;受扩底桩变径影响,同一根试验桩的同一土层在变径处以上3 m范围内桩侧摩阻力较其3 m以上发挥值低15%~40%。试验研究成果可为扩底桩设计与施工提供借鉴与参考。To study the bearing characteristic of drilling expanded bottom cast-in-situ pile,static load tests of two expanded bottom bored piles of different shape and one equal diameter pile were conducted,as well as pile stress tests of the expanded bottom bored piles.Test and data analysis results show that the influence of sediment and soil softening on the bearing capacity of expanded bottom pile is relatively sensitive.In addition to directly affecting the pile end resistance,it will also produce the weakening effect of pile side friction resistance.The shape of the enlarged head affects the slag removal effect at the bottom of the hole,and the high pressure grouting at the bottom of the pile can eliminate or partially eliminate the influence of the sediment.The development value of the pile side friction resistance of the same soil layer of different test piles is not fixed.Affected by the diameter change of the expanded bottom pile,the pile side friction resistance of the same soil layer of the same test pile within the range of 3 m above the diameter change is 15%~40%,lower than the value of the pile side friction within the range of 3 m above the diameter change.The test results can provide reference for the design and construction of expanded bottom piles.

关 键 词：扩底灌注桩 桩底沉渣 扩大头形状 桩侧摩阻力 弱化效应 

分 类 号：TU473.1[建筑科学—结构工程]