预应力钢筋混凝土管输水阻力测试分析

Analysis on test of water conveyance resistance for prestressed concrete cylinder pipe

作为南水北调天津干线的前期工作,在天津市新地河泵站,对管径1.6 m的预应力钢筋混凝土管(PCCP)进行了输水阻力测试,测试流量范围3～7 m3/s,共测试13组数据,据此计算出PCCP的当量粗糙度k值和糙率n值.实测表明,k值不随水头损失hf和雷诺数Re变化.根据测试出的k值,可进一步推算不同管径的糙率n值.测试结果表明,现代混凝土构件的表面糙度与传统相比有了很大变化,PCCP-E型管的k值已接近于管内壁涂敷涂料的k值.

As the preparation work for Tianjin Main Route of the South-to-North Water Transfer Project, the water conveyance resistance is tested with the flow rate ranged from 3 m^3/s to 7 m^3/s and 13 groups of data are obtained for the prestressed concrete cylinder pipe（PCCP）with the diameter of 1.6 meters at the Xindihe Pumping Station, with which the equivalent roughness and the coefficient of roughness for the pipe are calculated, The test shows that the roughness is not a function of both the head loss and Reynolds number. Based on the k-value given by the test, the coefficient of roughness of the pipes with various diameters can be further derived. The result of the test demonstrates that the surface roughness of the modem concrete member is quite different from that of the traditional ones, and then the k-value for the pipe of PCCP-E type approaches the value for the pipes with the inner wall coating as well,