TIRE SHREDS AS LIGHTWEIGHT RETAINING WALL BACKFILL - ACTIVE CONDITIONS

A 4.88-m-high retaining wall test facility was constructed to test tir e shreds as retaining wall backfill. The front wall of the facility co uld be rotated outward away from the fill and was instrumented to meas ure the horizontal stress. Measurement of movement within the backfill and settlement of the backfill surface during wall rotation allowed e stimation of the pattern of movement within the fill. Tests were condu cted 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 f rom the three suppliers. Moreover, horizontal stress at this rotation for tire shreds was about 35% less than the active stress expected for conventional granular backfill. Design parameters were developed usin g two procedures; the first used the coefficient of lateral earth pres sure and the other was based on equivalent fluid pressure. The inclina tion of the sliding plane with respect to horizontal was estimated to range from 61 degrees to 70 degrees for the three types of shreds.