埋地球墨铸铁供水管道轴向拉拔试验

Pullout Test Research on the Underground Water Pipelines

目的对埋地球墨铸铁管道进行抗拉静载试验,分析管道接口力学性能以及砂土对管道产生的摩擦力,确定地震作用下管道接口抗拉拔强度,以该指标作为判断管道抗震性能的依据.方法管道采用T型胶圈连接的柔性接口,在覆土的情况下,对150 mm和200 mm两种管径的管道注水后,分别进行6次静力拉拔试验.结果直径150mm和200 mm管道的接口位移所承受的最大值分别为56.97 mm和57.52 mm.水压随着位移的增大基本没有太大变化,直到管道接口破坏,管体内水压才突然下降.结论球墨铸铁管柔性接口管道抗震性能较好,管径越大抗震性能越好.管道与砂土之间的相对位移是影响管道抗震性能的主要因素之一,增加承插式管道的承口深度有助于提高管道的抗震性能.

Through the analysis of the experiment of the flexible joint ductile cast iron pipeline, the joint strength and the friction between the sand and pipelines were studied, and the resistance drawing strength of the pipelines was determined, which could be used as an index to evaluate their seismic performance. Pullout test of the T-type flexible joint of the ductile cast iron pipelines with two kinds of diameters was carded out under the situation of water injected in the pipelines and soil coving them. Strength-displacement curves and hydraulic pressure-displacement curves were measured and the seismic influencing factors were analyzed based on these curves. The following conclusions are gotten：the seismic performance of the flexible joint ductile cast iron pipeline is good; the seismic performance of the ductile cast iron pipeline is related to its diameter, i. e. the greater the diameter is, the better seismic performance is;the relative displacement between the sand and pipelines is one of the main factors influencing the seismic behavior of pipelines ;increasing the depth of Socket-mouth in the pipeline will improve the pipeline＇s seismic performance.