Because little field performance experience was available for high-density polyethylene pipe under high earth load, a test installation was carried out with a 24-in.-Diameter (610 mm) pipe placed beneath a 100-ft-high (30.5 M) embankment. The pipe was corrugated; and in some sections, a smooth interior wall was added. The pipe was embedded in a shallow trench near the base of the embankment and backfilled with compacted crushed limestone. Instruments were used to measure pipe wall strain, pipe diameter change, earth pressure acting onthe pipe, vertical soil strain adjacent to the pipe, and pipe wall temperature. The paper presents results obtained with 95 ft (29 m) of fill over the pipe. No material distress was observed. The pipe remained relatively round, with about 4% vertical diameter decrease and 0.4% Horizontal diameter increase. The average compression strainat the springline was 1.2%, And the bending strain was 0.3%. The vertical deflection was primarily the result of a 1.4% Circumference shortening. This shortening resulted in substantial positive arching--measured earth pressure on the pipe crown was only about 20% of thevertical embankment earth pressure. This paper appears in transportation research record no. 1231, Analysis, design, and behavior of underground culverts.
Abstract