Development of Testing Procedures to Study the Impact of Erosion Voids on Buried Pipes

The recently commissioned Deep Burial Simulator facility at Queen’s University allows for a water table to be raised and lowered within a test pit. The 3 m wide, 5 m long, and 4.6 m deep pit uses standpipes to supply water to the system and to control the elevation of the water table. In the current work, procedures are developed to create erosion voids adjacent to two different buried pipe specimens that initially have intact soil support conditions—tests to investigate how the volumes and shapes of those erosion voids develop. The first specimen was a two-segment reinforced concrete pipe sample with a nominal inner diameter of 825 mm and the second was a 900 mm diameter circular corrugated steel pipe. The erosion voids were created from water and soil infiltration into each of the structures through simulated defects: a leaking joint between the two pipe segments in the reinforced concrete pipe test and areas of complete wall loss along the haunch positions in the corrugated steel pipe test. The erosion voids were created from multiple infiltration events and the final geometry of all voids was captured by injecting polyurethane expanding foam into the void space before the structure was exhumed. An erosion void with an approximate total volume of 0.02 m3 was created beside the reinforced concrete pipe specimen and multiple larger erosion voids with volumes around 0.2 m3 were created beside the corrugated steel pipe specimen.