Behavior of Buried Water Supply PVC Pipe Model with Rock Support on the CTEd-2 Centrifuge Machine

Urban expansion increasingly challenges the planning of water supply infrastructure, particularly in preventing pipe leakage caused by substandard installation or inconsistent support in confined areas. Field investigations of buried pipe behavior are costly and difficult to control; thus, this study employs the CTEd-2 geotechnical centrifuge to develop and test a model of a buried PVC water supply pipe with rock support under controlled laboratory conditions. The research involved: (1) developing testing equipment for the centrifuge model, (2) preparing artificial clay to simulate soft Bangkok Clay, and (3) examining the flexural behavior of pipes supported by rock at their midpoint, under 20 times normal gravity (1:20 scale). Three testing scenarios were explored: (1) the effects of one and two wheel-load positions on sand surfaces at varying burial depths, (2) the influence of different trench widths, and (3) comparisons of wheel-load effects with and without rock support. Results indicate that burial depth significantly affects pipe behavior, with the shallowest depth causing the greatest flexural deformation, which diminishes as depth increases. Trench width also plays a role; narrower trenches reduce the load's impact due to sand arching, which helps redistribute pressure and limit deformation. Additionally, the number and position of wheel loads influence flexural response, though deformations near the pipe ends remain relatively unchanged.