Md. Mahabub Rahman
The main aim of the present research is to assess the potential for soil liquefaction in the subsoil in twelve selected locations belonging to the Bogura Sadar area, using field-sponsored geotechnical data. This assessment utilizes the well-known, semi-empirical method developed by Seed and Idriss that considers earthquake magnitude, overburden pressure, the corrected value of SPT-N, peak ground acceleration (PGA), soil unit weight and depth of water table. The outcome is that, for a 6.5 MW earthquake, two zones have very high and seven zones have moderate susceptibility to liquefaction, and the remaining areas are less susceptible. The profiles of the factor of safety (FS) show that these values are greater than 1.0 at depths of 1.5 and 12 m for all the zones. However, at depths from 3 m to 9 m, most layers have FS values of less than or equal to 1.0, suggesting that the same seismic event may cause a liquefaction risk. In order to prevent or reduce this risk, surcharge loading is used as an efficient defensive action. The findings confirm that 400 kPa of surcharge guarantees to be on the safe side with respect to liquefaction in all considered zones. In general, the results contribute useful information for mitigating geotechnical hazards and realizing seismic resilience in the study region.