水利水电行业回填钢管设计若干问题探讨

Discussion on some problems in design of buried steel pipe for water conservancy and hydropower industry

回填钢管在水利水电行业应用逐渐增多,但是国内该行业中尚未有关于回填钢管的设计规范。通过对比分析CECS规范、日本规范和ASCE规范,对回填钢管设计中的荷载计算及组合、弯矩计算、允许应力和安全系数等内容进行探讨。研究表明:3种规范所采用的设计理论、设计思路基本相同,但在荷载计算、荷载组合、内力计算等方面存在差别,适用于不同的情况;考虑到水利水电行业回填钢管通常管径大、内压高、刚度小的特点,在设计时建议考虑管重、水重及外水压力等荷载,内水压力的计算宜遵循水利水电行业规定,采用棱柱荷载计算管顶竖向土压力;建议参考日本规范,在弯矩计算公式中直接加入内水压力项,定量计算内水压力对弯矩的折减作用。

The application of buried steel pipe has gradually increased in water conservancy and hydropower industry,but domestic design specifications for the buried steel pipe is still absent.We discuss the load and combination,bending moment calculation,allowable stress and safety factors of the buried steel pipe by comparing the differences in CECS,Japanese and ASCE specifications.The research showed that design theories and ideas adopted by these specifications were the same,but there were differences in the load calculation and combination,internal force calculation,which were adapted to different situations.The buried steel pipe usually had a large diameter,high internal pressure and low rigidity in the water conservancy and hydropower industry,therefore it was recommended to consider all the loads such as pipe weight,water weight,and external water pressure in the design.The calculation of internal water pressure should follow the hydropower industry regulations,and the vertical soil pressure at the top of the pipe is advised to adopt prism load.It was also recommended to refer to the Japanese specification to directly add the internal water pressure term in the bending moment calculation formula to quantitatively calculate the reduction effect of internal water pressure on bending moment.