Study on Behavior of Ductile Iron Pipelines with Earthquake-Resistant Joints Buried across a Fault

Abstract

This study is focusing on behavior of ductile iron pipelines with earthquake-resistant joints buried across a fault used widely for water pipelines in Japan. It is necessary to design a pipeline carefully in case of crossing a fault, because the partially large displacement occurs on the pipelines when a fault moves by an earthquake. Although there is some research on behavior of steel pipelines which cross a fault, there are few studies of ductile iron pipelines. In this study, we investigated the behavior of pipeline buried across a fault by simulation analysis and verification experiment. As a result, we clarified that the earthquake resistant joint nearest to a fault began to move when a fault began to move, and then the joints in line began to move when the expansion, contraction and deflection angle in the joint nearest to a fault reached its capacity. In addition, we confirmed that we could evaluate the safety of pipeline against the fault movement by deflection angle in each joint. As a result, using colors with large bending performance rather than straight pipe sockets of shortening the pipe length was effective to increase the safety of pipeline near a fault.