Tire Shreds as Lightweight Retaining Wall Backfill: Active Conditions

Abstract

A 4.88-m-high retaining wall test facility was constructed to test tire shreds as retaining wall backfill. The front wall of the facility could be rotated outward away from the fill and was instrumented to measure the horizontal stress. Measurement of movement within the backfill and settlement of the backfill surface during wall rotation allowed estimation of the pattern of movement within the fill. Tests were conducted with tire shreds from three suppliers. The horizontal stress at a rotation about the base of 0.01H was about the same for tire shreds from the three suppliers. Moreover, horizontal stress at this rotation for tire shreds was approximately 35% less than the active stress expected for conventional granular backfill. Design parameters were developed using two procedures; the first used the coefficient of lateral earth pressure and the other was based on equivalent fluid pressure. The inclination of the sliding plane with respect to horizontal was estimated to range from 61 deg (1.06 rad) to 70 deg (1.22 rad) for the three types of shreds.