Field Instrumentations of a Two-Tiered Geogrid-Reinforced Soil Wall Backfilled with Soil-Rock Mixture

There have been very few studies on the application of soil-rock mixtures as the backfill materials of geosynthetic reinforced soil retaining walls. Nonetheless, such application, if successful, can considerably improve the cost-effectiveness of reinforced soil walls. In this study, a17 m high two-tiered reinforced soil wall backfilled with soil-rock mixture was instrumented for its responses under gravity load. The instrumentation continued for more than one year after the end of construction. It is found that soil-rock mixture with small rock content (<30%) may be used as the backfill materials of geogrid-reinforced retaining walls, but special attentions should be given to the compaction quality and the interaction between geogrid and soil-rock mixture. Reinforcement slippage is possible because of the large particles. Compressibility difference between reinforced and unreinforced backfill might lead to rotation of the upper tier when it is high.