Evaluation of liquefaction response of waste foundry sand using energy dissipation approach

The reuse of waste foundry sand (WFS) as a sustainable alternative to natural sand in geotechnical backfill applications necessitates a thorough understanding of its behaviour under dynamic loading. This study presents an experimental evaluation of the dynamic and liquefaction behaviour of WFS using cyclic triaxial testing. A comprehensive test programme was conducted on cylindrical specimens of 50 mm dia. and 100 mm height under stress-controlled cyclic loading. Tests were performed over a range of loading frequencies (0·1–5 Hz) and cyclic stress ratios (CSR = 0·15–0·25) to simulate seismic and traffic-induced loading conditions. For comparison, selected tests were also carried out on natural silica sand under identical conditions. The response of WFS was assessed in terms of excess pore water pressure generation, cyclic deformation characteristics and the number of cycles to liquefaction. The results indicate a clear influence of loading frequency and CSR on the liquefaction resistance of WFS. Compared with silica sand, WFS exhibits comparable dynamic performance. This study can also be useful for assessing seismic response and stability analysis of WFS landfills.