管道承插式接口轴向力学性能试验研究与数值模拟

通过球墨铸铁供水管线承插式接口抗拉静载力学性能试验，分析管道接口轴向的拉伸力学性能和破坏模式，并建立相应管道接口受力分析的有限元数值模型。在外部无覆土、加压注水条件下，对球墨铸铁输水管道承插式接口进行拟静力拉拔试验，模拟其在地震作用等往复荷载下的轴向受力与变形特征。试验结果表明，加载方式以及管道内部水压等对接口的轴向抗拉力学性能和破坏方式的影响不大，抗拉极限位移达到60 cm。基于OpenSees计算平台建立管道接口有限元模型，并对试验结果进行了模拟，结果表明建立的管道接口有限元模型能够较好地模拟管道接口在轴向往复荷载作用下的刚度退化和耗能等力学特征，为埋地管道在复杂轴向荷载作用下的受力分析和性能评估提供了必要的试验数据和计算模型。

EXPERIMENTAL AND NUMERICAL STUDY ON AXIAL MECHANICAL PROPERTIES OF PIPELINE UNDER PSEUDO-STATIC LOADING

A series of pseudo-static tensile tests were performed on the push-on joints of ductile iron water pipeline specimens to investigate the axial mechanical properties and failure mechanism of the joints. A new finite element model for the push-on joint was also developed in this study. The pseudo-static tests were carried out on the push-on joints of ductile iron pipeline specimens using both monotonic and cyclic loading to investigate the behavior of the joints under repetitive axial loading, such as seismic loads during an earthquake event. It was found that the effects of the different loading protocols and internal water pressure on the axial response and failure modes of the push-on joint were negligible in this experimental study. The tension displacement limit of the joints reached 60 cm. Finally, a new finite element joint model was developed in OpenSees to simulate the axial behavior of the push-on joint observed during the experiments. The proposed numerical joint model can well capture the characteristic axial response of the joint, such as axial stiffness degradation and energy dissipation.Both the experimental and numerical results provide a support in assessing the performance of the push-on joints of water pipelines subjected to complex axial loading.