Physical modelling of advanced soil-buried pipe interaction problems

Buried pipelines for transporting water, oil and natural gas are often subjected to ground movement due to traffic loads, earthquakes, ground subsidence, tunnel excavation etc. Design of pipes in areas where ground movement is expected requires a comprehensive understanding of soil-pipe interaction mechanisms. In practice, Winkler springs are usually used to quantify the soil-pipe interaction. Current design guidelines such as ALA (2005) and PRCI (2009) for determining the properties of these springs are based on some assumptions that might not be met in practice. e.g. the backfill is uniform clean sand and is either dry or fully saturated, or the mechanical characteristics of sand and the failure mode does not change with soil stress levels. This thesis presents a comprehensive experimental investigation to study the effects of (large) pipe embedment depth, the relative density, and the degree of saturation of the pipe backfill on the developing soil reaction on pipes subjected to vertical upward, lateral and vertical downward relative movements. The presented study comprises 1-g physical model tests performed on rigid buried pipes with diameters 37.5mm to 150mm.