Structural and Hydraulic Performance of 1500-mm Smooth-Interior High-Density Polyethylene Pipe in Soil Cell

Soil cell tests have been used for decades to evaluate the structural performance of a variety of pipes. The structural performance of a 1500-mm (60-in.)-diameter, corrugated-exterior, smooth-interior high-density polyethylene pipe in a soil cell with two different backfill strengths is presented, and the results are compared with the values predicted theoretically. Specifiers demand assurance of the long-term hydraulic performance of smooth-interior corrugated polyethylene pipe. Fortunately, a mathematical model that allows for the estimation of the Manning value by using measurable pipe dimensions and flow characteristics is available. A discussion of the geometric changes in the interior pipe surface measured during the soil cell test is included, and an estimate of the resulting Manning values is provided. The results indicated a maximum increase in Manning values of approximately 3 or 10 percent, depending on backfill, for pipe buried within current industry recommendations for cover height.