塑料套管混凝土桩挤土效应的非侵入可视化研究  

Non-intrusively visualization on squeezing effect of plastic tube cast-in-place concrete piles

作　　者：齐昌广[1] 左殿军[2] 刘干斌[1] 郑荣跃[1] 

机构地区：[1]宁波大学建筑工程与环境学院,浙江宁波315211 [2]交通运输部天津水运工程科学研究所岩土工程研究中心,天津300456

出　　处：《岩石力学与工程学报》2017年第9期2333-2340,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：宁波市自然科学基金资助项目(2017A610317);中央级公益性科研院所基本科研业务费专项资金项目(TKS160101;TKS160109)~~

摘　　要：结合透明土、粒子图像测速(PIV)和近景摄影测量3种技术,研究塑料套管混凝土桩(TC桩)的挤土效应,并对周围土体的变形规律进行探讨,且与传统静压桩打设引起的土体变形进行对比。试验结果表明:圆锥桩尖引起的最大变形量相比平底桩尖的降低了40%;而在平底桩尖TC桩的成桩过程中,影响区域扩展到了远离桩体中心线11倍桩径处,而对于圆锥桩尖,则为6倍桩径;沉管上拔引起的土体移动主要发生在上拔前期,对于圆锥桩尖TC桩,其沉管上拔过程引起的最大位移量和影响区域分别约为平底桩尖的57%和33%,然而,在TC桩成桩过程中,沉管打设是引起土体变形的主导因素,沉管上拔引起的土体恢复变形较小;在与TC桩沉管直径相同条件下,传统静压桩打设引起的土体变形量与TC桩的相一致,然而其影响区域略小。The squeezing effect of plastic tube cast-in-place concrete piles（TC pile） was investigated by combining with three technologies of transparent soil,particle image velocimetry（PIV） and close-range photogrammetry. The soil deformations caused by TC pile installation were explored and compared with those induced by conventionally jacked pile. The test results show that the maximum displacement caused by casing jacking for expanded-conical-base pile is decreased by 40% compared with that for expanded-flat-base pile. The affected zone extends as far as 11 times the radius of pile shaft at the surface in the case of the flat shoe,whereas in the case of the conical shoe,the affected zone up to 6 times the radius of pile shaft from the pile centerline. The soil movement caused by casing extraction occurs mainly in the early stage of extraction. The maximum displacement and affected zone caused by casing extraction for the conical base are about 57% and 33% of those for the flat base respectively. However,during the jacking of TC pile,the casing driving is the dominant factor causing the soil deformation,while the recovery of soil deformation caused by casing extraction is small. The displacements generated by jacking a conventional pile with the same diameter is consistent with those induced by TC pile installation,but its affected zone is slightly smaller.

关 键 词：桩基工程 塑料套管混凝土桩 透明土 非侵入可视化 挤土效应 粒子图像测速(PIV) 

分 类 号：TU473[建筑科学—结构工程]