Abstract
This study includes the determination of the engineering physical parameters of a proposed urban expansion site at Khamis Mushait city, SW Saudi Arabia. The seismic refraction survey as a noninvasive seismic technique was used to determine the P wave velocity profile of the soil section in the studied site. This method provides a simplified characterization of subsurface in two-dimensional depth-velocity profiles. Seismic records obtained were processed and analyzed by SeisImager software to obtain one-dimensional P wave velocity (Vp) distribution. The measured P wave velocities were used to estimate relative density, N value, modulus of elasticity, uniaxial compression strength, ultimate tensile strength, ultimate bearing capacity, allowable bearing capacity, Poisson's ratio, and rock quality designation. The results indicate that the investigated site is composed mainly of two soil layers. The top layer is interpreted as loose incompetent soil sediments (alluvial sediments) to the depth of 5 m with V (p) ranging between 300 and 880 m/s. This layer is underlain by the second competent soil layer with thickness reaching 18 m and V (p) ranging between 1,097 and 2,626 m/s. The second layer is considered as the foundation layer, and its determined engineering physical parameters are vital information for the engineers in construction and urban development of this site.