Behavior of a branched buried MDPE gas distribution pipe under axial ground movement

ABSTRACT: Medium density polyethylene pipes (MDPE) are widely used for gas distribution systems in Canada and worldwide. These pipes are often exposed to relative ground movements resulting from landslides and earthquakes. The effects of the relative ground movement on the pipes are influenced by the presence of lateral branches and the tee-joint connecting the branch. Only a limited study is currently available in the literature on studying the behavior of branched pipe subjected to ground movements. This paper presents an experimental investigation of a branched MDPE pipe subjected to axial ground movement. A test with a 60.3 mm diameter gas distribution pipe is conducted using the laboratory facility at Memorial University of Newfoundland. Pipe wall strains and soil pressures around the pipe are measured to capture the mechanism of soil-pipe interaction. Test results reveal that the pullout force and pipe wall strains are significantly influenced by the tee-joint. The elongation of the flexible MDPE pipe also contributes to the pipe deformations and wall strains.