Response of buried HDPE double-wall corrugated pipe in sand under lateral pipe-soil relative movement

High-density polyethylene (HDPE) double-wall corrugated pipes have been extensively adopted as sanitary and stormwater pipes. Earlier research primarily focused on pipes with plain and smooth walls, and thus ignored the effect of ring stiffness due to corrugation on the pipe bending behavior. In order to characterize the effect of ring stiffness on HDPE double-wall corrugated pipe behavior, in-air three-point bending tests were conducted. It is demonstrated that the ring stiffness had negligible effect on the pipe's flexural rigidity, while the pipe wall thicknesses at valley and liner played an important role. Subsequently, six large-scale lateral dragging tests were carried out for such pipes buried in sand. The ring stiffness was identified to primarily influence the circumferential strains, as these strains decreased with the increase of ring stiffness in the pipe at 1/4 and 1/2 spans. However, the ring stiffness had insignificant effect on the pipe bending strains and load-displacement responses. Current design guidelines significantly overestimated the peak soil resistance and underestimated the yield displacement for HDPE double-wall corrugated pipes. The longitudinal strains can be accurately estimated by an analytical method at small pipe end displacements, before the mobilization of peak soil resistance.