The existing design guidelines for buried flexible pipes are limited to depth up to 10 m . The increasing use of difficult terrains for infrastructure, landfills, and residential and industrial developments has prompted installation of drainage pipelines under 20–30 m high fills. This paper presents the behavior of an instrumented flexible pipe buried under a 47.1 m deep fill. For filling above 20 m , the measured vertical stress above the pipe exhibited a concave distribution, corresponding to 90 and 110% of the average vertical pressure at the center and edges of the pipe, respectively. The measured results suggest that a triangular lateral pressure distribution can lead to overly conservative and uneconomical results for high fills while Spangler’s analysis is unconservative. Based on the measured results, a revised vertical and lateral earth pressure diagram was proposed for the design of flexible pipe under high fills >20 m . This paper proposes closed-form analyses for estimating the moments and dis...