围堰封底混凝土与钢管桩粘结力模型试验研究-学兔兔 www.xuetutu.com.pdf

桥梁建设2014年第44卷第6期(总第229期
Bridge Construction, Vol 44, No6, 2014(Totally No 229)
69
文章编号:1003-4722(2014)06-0069-06
围堰封底混凝士与钢管桩粘结力模型试验研究
崔清强·2
(1.中铁大桥局集团桥科院有限公司,湖北武汉430034
2.桥梁结构安全与健康湖北省重点实验室,湖北武汉430034)
摘要:目前跨江河大桥常采用围堰进行下部结构施工,围堰主要靠钢管桩和封底混凝土之
间的粘结カ抵抗水浮力和其他荷载,为研究围堰封底混凝土与钢管桩间粘结力的主要影响因素,并
得到粘结力的可靠取値,制作了4组9个国堰封底混凝土与钢管桩粘结力模型。模型中部采用中
空钢管模拟钢管桩,下部的封底混凝土按现场施工工艺浇筑,在钢管桩上部设置反向牛腿与下部封
底混凝土构成自平衡加栽体系,中间采用千斤顶模拟实际围堰的受力状况进行分级加載试验,并进
行了仿真计算分析。结果表明:C25封底混凝土粘结力为0.3~0.54MPa,目前设计使用的粘结カ
经验值偏安全;混凝土强度等级越高,粘结力越大;封底混凝土厚度与钢管桩直径的比值对粘结力
影响不明显;施工エ艺和钢管桩表面状态对粘结力影响较大。
关键词:深水桥梁;国堰;封底混凝土;钢管桩;粘结力;模型试验;仿真计算
中图分类号:U443.162;U446
文献标志码:A
Model Test Study of Bonding Forces Between Cofferdam
Base Sealing Concrete and Steel Pipe Piles
CUI Qing-qiang
(1. Bridge Science Research Institute Ltd, China Railway Major Bridge Engineering Group, Wuhan 430034,
China; 2. Key Iaboratory of Bridge Structure Safety and Health of Hubei Province, Wuhan 430034, China)
Abstract: Nowadays, the substructures of the major bridges crossing the rivers have been
commonly constructed by the steel cofferdams. The cofferdams resist the water buoyant forces
and other loads, mainly relaying on the bonding forces between the cofferdam base sealing con
crete and the steel pipe piles. To study the major factors having influences on the bonding forces
and to obtain the reliable values of the forces, 4 groups of 9 models for the bonding forces were
prepared. In the models, the hollow steel pipes were used to simulate the steel pipe piles and the
base sealing concrete at the lower parts of the models was cast according to the construction tech
nology actually used in the field. At the upper parts of the steel pipe piles in the models, the re-
verse brackets were arranged and together with the base sealing concrete at the lower parts, the
self-balanced loading systems were formed. At the middle parts of the pipe piles, the jacks were
used to generate forces and to simulate the actual force conditions of the cofferdams, the model
tests were carried out by applying load in steps and the simulation calculation and analysis were
made as well. The results of the tests show that the bonding forces of the C25 base sealing con
crete is 0. 3-0. 54 Mpa and the empirical values of the forces having been used in the current de
sign are a bit too safe. The greater the concrete strength is, the greater the bonding forces will
be. The ratios of the base sealing concrete depth and the steel pipe pile diameters do not have sig
nificant influences on the bonding forces while the construction technology and the steel pipe pile
收稿日期:2014-06-27
作者简介:崔清强,高级工程师,O-mail:cuiqungqiang(@126.com。研究方向:桥梁试验检测与研究