Reduction of Surcharge Induced Earth Pressure on Rigid Non-yielding Retaining Wall Using Relief Shelves

The present study is conducted to investigate the effectiveness of relief shelf to reduce the lateral thrust on rigid non-yielding retaining wall, through a small-scale physical model test in laboratory. The height of the model retaining wall was 700 mm, and five earth pressure sensors were used to measure the lateral pressures along the height of the retaining wall with and without relief shelves. A maximum surcharge pressure of 50 kPa was applied on the backfill. From the results of the study, it is found that relief shelves are effective in reducing total thrust on wall. A parametric study is also carried out on 8 m high wall having 3 relief shelves by varying the width of shelves, through numerical analyses using FLAC^3D. The study reveals that relief shelves having width factor ranging 0.3–0.8 can reduce total thrust on the wall in range of 11–26%. Among all the cases of retaining wall with relief shelves analysed in the present study, retaining walls with shelf width of 1.4 m (width factor of 0.7) exhibited substantial reduction in lateral thrust, without leading to excessive deflection of relief shelves and backfill surface settlement.