埋藏式压力钢管加劲环抗外压稳定计算方法的比较与应用  

Comparison and application of calculation method for stability against external pressure of stiffening ring for embedded steel penstock

作　　者：鲁志航 彭越尧 伍鹤皋[1] 石长征[1] LU Zhihang;PENG Yueyao;WU Hegao;SHI Changzheng(State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, Hubei,China;PowerChina Zhongnan Engineering Corporation Limited, Changsha 410014, Hunan,China)

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072 [2]中国电建集团中南勘测设计研究院有限公司,湖南长沙410014

出　　处：《水利水电技术》2020年第7期46-52,共7页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金资助项目(51409194)。

摘　　要：对埋藏式压力钢管加劲环的抗外压稳定分析,国内外常用的计算方法有Amstutz法、Jacob-sen法和《水电站压力钢管设计规范》(NB/T 35056—2015)(以下简称《规范》)中的强度公式。对这三种计算方法进行了比较分析,得到以下结论:Amstutz公式和Jacobsen公式计算的临界外压力随缝隙值的增大而减小,《规范》强度公式没有考虑缝隙值的影响,其计算得到的临界外压力与缝隙值无关;三种方法计算所得的临界外压力均随加劲环高度、管壁厚度和钢材屈服强度的增大而增大,随加劲环间距的增大而减小;《规范》强度公式计算所得的加劲环临界外压力相对Amstutz公式和Jacobsen公式较小,采用《规范》强度公式在外水头小于130 m时明显偏保守,经过比较分析后,建议将Jacobsen法作为国内钢管设计规范中埋藏式压力钢管加劲环抗外压稳定的主要计算方法之一。For the analysis of the stability against external pressure of the stiffening ring for the embedded steel penstock,the commonly used calculation methods at home and abroad include Amstutz method,Jacobsen method and the strength formula spe-cified in the“Design Code for Steel Penstocks of Hydroelectric Stations”(NB/T 35056—2015)(hereinafter referred to as the code).The three calculation methods are comparatively analyzed herein,and then the conclusion is obtained as the follows:the critical external pressures calculated by both Amstutz formula and Jacobsen formula are decreased along with the increase of the value of gap,however,the influence from the value of gap is not considered in the strength formula specified in the code,from which the critical external pressure obtained from the calculation is not related to the value of gap.All the critical external pressures obtained from the three calculation methods are increased along with the increases of the height of stiffening ring,the thickness of pipe-wall and the yielding strength of the steel material and are decreased along with the increase of the spacing among the stiffening rings.The critical external pressure of the stiffening ring obtained from the calculation made by the strength formula specified in the code is less than those obtained from both Amstutz formula and Jacobsen formula,and then the adoption of the strength formula specified in the code is obviously more conservative when the external water head is less than 130 m.Through the relevant comparative analysis,it is suggested to take Jacobsen method as one of the main methods for the calculation of the stability against external pressure of the stiffening ring for the embedded steel penstock specified in the relevant steel penstock design code in China.

关 键 词：埋藏式压力钢管 加劲环 抗外压稳定 计算方法 临界外压力 

分 类 号：TV732.1[水利工程—水利水电工程]