论文部分内容阅读
对频率法计算竖直拉索索力的原理和方法进行分析与评价,指出工程实际拉索与理想匀质拉索模型的区别,强调端部性质对频率法测量竖直拉索索力的影响。根据实际拉索两端一般具有锚杯和连接筒的构造特点,提出“三段式、两端刚接”振动模型;延用匀质拉索索力计算公式模型,考虑对匀质比例变量进行修正从而获得实际比例变量;采用有限单元法对端部性质进行参数影响分析,深入研究了比例变量修正系数λ随长度修正系数λL和刚度修正系数λI的变化规律。比例变量修正系数λ与长度修正系数L Lλ=P成正比例函数关系,其函数方程斜率为刚度修正系数λI;根据刚度修正系数λI随刚度比PI增大而增大,随索力T增大而减小等变化规律,构造刚度修正系数λI函数方程;并最终建立可计入端部性质影响的修正索力计算公式。数值分析和工程实例计算结果均表明:当长度比PL≥0.08时,端部性质对计算索力的影响随索长的减小而迅速增大;当长度比PL≥0.14时,匀质索力计算公式已经不能正确计算索力,其计算偏差可达50%以上;而本文建立的修正索力计算公式始终能够对长度比PL≤0.5拉索做出正确的计算索力,其计算精度能够满足工程要求。
The principle and method of calculating the vertical cable force by the frequency method are analyzed and evaluated. The difference between the actual cable and the ideal homogeneous cable model is pointed out, and the influence of the end property on the vertical cable force measured by the frequency method is emphasized. According to the structural characteristics of anchorage cup and connecting barrel at both ends of the actual cable, the model of “three-stage and two-end just-connected” vibration model is presented. Using the model of uniform cable tension calculation formula, And the actual proportional variables were obtained. The influence of parameters on the properties of the end was analyzed by the finite element method. The variation regularity of the correction coefficient λ of the proportional variable with the length correction factor λL and the rigidity correction factor λI was deeply studied. The proportional variable correction factor λ is proportional to the length correction factor L Lλ = P, and the slope of the functional equation is the stiffness correction factor λI. According to the rigidity correction factor λI increasing with stiffness ratio PI increasing, Reduce the law of variation and construct the function formula of stiffness correction coefficient λI. Finally, a formula for calculating the corrected cable force that can be included in the influence of the end property is established. The results of numerical analysis and engineering examples show that when the length ratio PL ≥ 0.08, the influence of the end properties on the calculation of the cable force rapidly increases with the decrease of the cable length. When the length ratio PL ≥ 0.14, the homogeneous cable force The calculation formula has been unable to calculate the cable force correctly, and the calculated deviation can reach more than 50%. The formula for calculating the revised cable force established in this paper can always make the correct calculation of cable force for the cable length ratio PL≤0.5, Engineering requirements.