Impacts of Extreme Hydrological Events on the Behavior of Buried Stormwater Pipe

Abstract

This study focused on estimating the strength and deformation behavior of buried concrete pipe subjected to heavy rainfall-induced flooding, soil infiltration, leaks from the buried pipe, and erosion of the foundation soil. A sample stormwater pipe with a diameter of 0.9 m, a thickness of 0.12 m, and a length of 5 m was considered for the investigation. The maximum flood height and the rainfall intensity were chosen based on the record of Hurricane Florence in September 2018. The soil properties were obtained from a soil report for the Wilmington, North Carolina area. A coupled flow–deformation finite-element code was used to investigate the impacts of single hazards (flooding, soil infiltration, and leakage), two hazards (flooding and soil infiltration, flooding and leakage, and soil infiltration and leakage), and three hazards (flooding, soil infiltration, and leakage and flooding, soil infiltration, and erosion) at a time. Furthermore, several parametric studies were carried out to examine the effect of embedment depth, flood head, infiltration rate, and leakage rate on the behavior of the buried pipes. A maximum deflection, bending moment, and shear force of 21.69 mm, 83.4 kNm/m, and 192.2 kN/m, respectively, were observed at the top of the pipe when the longitudinal section was subjected to the simultaneous occurrence of rainfall, flooding, and pipe leakage. The pipe deformation gradually increased with the increase in flood head, infiltration rate, and leakage rate, and decreased with the embedment depth.