Malaysian Journal of Geosciences (MJG)

This work assessed the suitability of subsurface materials used for foundation development within a coastal environment prone to building subsidence and foundation distress. Seismic refraction tomography was employed to generate P- and S-velocities, which were then employed to generate elastic moduli that evaluated the competence of the subsurface strata for foundation development. The results indicated the presence of two subsurface strata with varying capacities for foundation development. The uppermost stratum had reduced values of seismic velocities and elastic moduli, indicating that the near-surface material was weak and had reduced load-bearing capacity. The second stratum, on the other hand, had higher measures of seismic velocities and elastic moduli, indicating its competence for supporting heavy engineering loads. The allowable bearing capacity increased from 77.51 -129.74 kN/m² in the uppermost stratum to 294.48 – 424.84 kN/m² in the second stratum, indicating the suitability of the lower stratum for supporting high-rise
foundations. Values of geotechnical moduli such as bulk modulus, constrained modulus, compressibility, and compliance corroborated these results, delineating the second stratum as having significantly higher stiffness and reduced compressibility compared to Layer 1. The results indicate a strong correlation between measures of seismic-derived elastic moduli and bearing capacities in coastal deltaic sediments. The integrated seismic-geotechnical approach was found useful for evaluating competent foundation layers and offers a cost￾effective strategy for reducing the risks of foundation distress in sedimentary environments.