大型U形薄壁渡槽预应力孔道摩阻试验研究  

Experimental Study on Friction Resistance of Prestressed Duct of Large U-Shaped Thin-Walled Aqueduct

作　　者：姚胜泉 YAO Shengquan(The 7th Engineering of China Railway 12th Bureau Group Co.Ltd,Changsha Hunan 410004,China)

机构地区：[1]中铁十二局集团第七工程有限公司,湖南长沙410004

出　　处：《铁道建筑技术》2023年第6期47-51,共5页Railway Construction Technology

基　　金：中铁十二局集团有限公司科技研发计划项目(2021-42)。

摘　　要：大型U型薄壁渡槽在采用后张法进行预应力张拉时,孔道摩阻是造成预应力损失的重要因素。目前在U形薄壁渡槽方面,关于孔道摩阻试验的研究并不多,并且相关规范只给出孔道摩阻系数取值范围。事实上,影响孔道摩阻损失的因素比较复杂。本文结合某原型试验渡槽,分别选择2束纵向和6束环向预应力钢绞线,开展孔道摩阻试验研究,并计算预应力孔道摩阻系数值。结果表明:圆形和扁形孔道摩阻系数μ分别为0.278、0.293,孔道偏差系数k为0.00354,均大于规范值,且环形预应力束其摩阻损失明显大于直线形预应力束。建议施工过程进一步加强波纹管定位精度,并适量加大预应力筋张拉力,以弥补预应力损失。When prestressing a large U-shaped thin-walled aqueduct by post-tensioned method,the channel friction is an important factor causing loss of prestress.At present,in the aspect of U-shaped thin-walled aqueduct,there is not much research on duct friction test,and the relevant specifications only give the value range of duct friction coefficient.In fact,the factors affecting duct friction loss are relatively complex.Based on a prototype test aqueduct,two longitudinal and six circumferential prestressed steel strands are selected to conduct duct friction test and calculate the friction coefficient of prestressed steel strand duct.The test results show that the friction coefficients/£of circular and flat channels are 0.278 and 0.293 respectively,and the duct deviation coefficient k is 0.00354,which is greater than the specification value,and the friction loss of the annular prestressing tendon is significantly greater than that of the linear prestressing tendon.It is suggested to further strengthen the corrugated pipe positioning accuracy during the construction,and provide a moderate amount of increase in the tension of prestressed reinforcement,in order to make up for the loss of prestress.

关 键 词：U形渡槽 摩阻试验 摩阻系数 偏差系数 

分 类 号：TV332.4[水利工程—水工结构工程] TV672.3