The performance of earth slopes reinforced with arrays of slender reinforcing members is currently being investigated. The reinforcing members used are fabricated from recycled plastics and other waste materials to form sections 90 mm (3.5 in.) x 90 mm (3.5 in.) x 2.4 m (8 ft) long. A design methodology was adopted to estimate the limit resistance provided by each member, which is then incorporated into conventional limit equilibrium slope stability analyses to calculate the improvement in the factor of safety under various reinforcement scenarios. Four field test sites were stabilized using recycled plastic reinforcement to demonstrate the effectiveness of the stabilization scheme and to evaluate the load transfer mechanisms between the soil and the reinforcement. One additional site was stabilized with similarly sized steel pipe members for comparison with the recycled plastic members. The stabilized slopes are performing well, whereas several control sections have experienced failures. The performance of each site is being monitored with field instrumentation to monitor lateral movements, pore pressures, strains within the reinforcing members, and the lateral loads applied to the members. Observations to date indicate that the slopes are performing well and that the reinforcing members have significant remaining capacity to maintain the stability of the slopes.
Abstract