砂土中螺旋挤土灌注桩受力性状模型试验研究  

MODEL TEST STUDY OF LOAD DEFORMATION BEHAVIOR OF SOIL DISPLACEMENT SCREW PILE IN SAND

作　　者：刘钟[1,2] 卢璟春[1,2] 张义[1,2] 李志毅[1,2] 贾玉栋[1,2] 

机构地区：[1]中冶建筑研究总院有限公司,北京100088 [2]中国京冶工程技术有限公司,北京100088

出　　处：《岩石力学与工程学报》2011年第3期616-624,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家财政部施工新技术研究与开发项目(财企[2006]376);住房与城乡建设部新型建筑结构技术研究开发项目(2008-K2-40)

摘　　要：利用自行研制的电动模拟钻机和桩基模型试验系统,在匀质砂土地基中进行新型螺旋挤土灌注桩模型试验,探索完全挤土型SDS桩的荷载传递规律和承载变形特性,发现桩侧摩阻力沿桩身呈异步发展,在小于0.2倍桩径的桩土相对位移范围内,桩侧摩阻力随桩土相对位移呈单调上升,且桩侧摩阻力远高于桩端阻力。通过SDS桩与CFA桩的试验结果对比发现,桩长因素对SDS桩承载变形特性的影响大于CFA桩,在桩长、桩径和地基都相同的模型试验条件下,SDS桩的极限承载力比CFA桩提高25%～70%。应用太沙基和派克的土压力原理及应力路径方法,阐明不同成桩工艺对桩周土体物理状态和力学指标的影响。结果表明,不同成桩工艺是引起SDS桩与CFA桩的承载变形性状出现差异性的主要原因。Using self-developed model drilling rig and pile model test system,a new type of soil displacement screw（SDS） pile in homogeneous sand has been studied to explore the load transfer mechanism and load deformation behaviors of full displacement pile.The investigations show that the skin friction along SDS pile is asynchronous distribution,within the soil-pile relative displacement of 20% pile diameter,the skin friction of pile due to soil-pile relative displacement is monotonous increase;and the shaft resistance of pile is much higher than the base resistance.Comparison of test results between SDS piles and continuous flight auger（CFA） piles,the factor of pile length played a more active role on the bearing capacity and deformation behavior of SDS piles than those of CFA piles.Under same model test conditions of the length,diameter of piles and soil,the ultimate bearing capacities of SDS piles are about 25% to 70% higher than those of CFA piles.Based on Terzaghi and Peck＇s theory of earth pressure and the stress path method as well,the main reasons are clarified about the difference of load deformation behavior resulted from disparate pile construction methods and installation effects which lead to change physical state and mechanical parameters of soil around SDS piles and CFA piles.

关 键 词：桩基工程 新技术 螺旋挤土灌注桩 模型试验 荷载传递机制 承载变形性状 

分 类 号：TU47[建筑科学—结构工程]