中文摘要：

针对小半径预应力束的实测伸长值比理论伸长值偏大这一现象，分析了影响小半径预应力束伸长值的各种因素，指出了小半径预应力束伸长值的构成特点。从研究张拉过程中小半径预应力束在波纹管内的位置变化入手，得出预应力柬由理想状态至波纹管变形前几何长度的变化量，引入挤压系数拿，给出了小半径预应力束的附加伸长值的计算公式，并提出了小半径预应力柬因波纹管形变引起的几何伸长值的计算方法。最后，通过多个模型数据对提出的小半径预应力束伸长值的计算方法进行校验。结果表明，实测伸长值与理论伸长值的偏差基本可控制在规范规定的±6％以内，完全能够满足小半径预应力束张拉的控制要求。

英文摘要：

In view of the phenomenon that the actual elongation of small radius prestressing tendons is slightly greater than the theoretic elongation, all kinds of factors that influencing the elongation of the tendons were analyzed and the constitution feature of the tensioning elongation of the tendons was pointed out. Started with the research of the position variation of small radius prestressing tendons in the corrugated pipe during the tensioning process, the variation in geometry length of the tendons from ideal state to that before the corrugated pipe distorts was obtained. The compression factor ξ was introduced, the formula to calculate the additional elongation of the tendons was given, and a calculation method of the geometry elongation which caused by the deformation of the corrugated pipe was proposed. Finally, the proposed method for calculating the tensioning elongation was verified by the data from several engineering projects. The results show that the deviation of elongation between measured value and calculated value can be controlled within the stipulation of the technical specification （ ± 6% ）, which can fully satisfy the control requirements of tensioning small radius prestressing tendons.