Interpretation of Buried Pipe Test: Small-Diameter Pipe in Ohio University Facility

Abstract

Two- and three-dimensional finite-element analyses were used to examine the response of a small-diameter leachate collection pipe tested at Ohio University. The influence of the cell boundaries was examined, and the implications of the loading system were investigated. The state of stress in the soil around the cell was studied, and its influence on the expected soil and pipe responses was evaluated. Comparisons between the pipe response induced in the test cell and that which was expected to occur in a real field installation were also made. It was found that nonuniform vertical and horizontal stress distributions different from those expected in real field installations developed in the test cell. This presents various difficulties associated with interpreting loading as an equivalent height of fill. At low load levels in the test cell the granular backfill adjacent to the pipe yielded as local bending developed under the rigid platform used to apply pressure to the ground surface. The decreased lateral support altered the mode of pipe deflection. At high load levels the response in the test cell was governed by soil failure, producing conditions not expected in a landfill environment.