Retaining Wall Model Test with Waste Foundry Sand Mixture Backfill

This paper presents experimental data concerning the lateral earth pressures acting against a small-scale retaining wall, with a backfill consisting of waste foundry sand (WFS) mixtures. The instrumented retaining-wall facility at Dongeui College in Korea was used in the testing. Two different testing methods were employed in this study: the controlled-strain method and the natural-strain method. The lateral earth pressures on the wall depend on the backfilling sequence, the type and drainage characteristic of the WFS mixture, and the shear strength of the mixtures. The mixtures of Green WFS performed best, showing a decrease in the lateral earth pressures and an increase in cohesion with curing time. The measured thrust lateral earth pressure of WFS mixtures was less than that observed for common residual soils in Korea. The stability of the retaining wall with respect to overturning and sliding, calculated using the measured lateral earth pressures, increased substantially with curing time. Judging from the retaining wall model test, the backfilling of a 6-m high retaining wall can be completed in two days with two backfilling stages.