Amplification Effects of Soil Stratification on Ground Stress Waves

Abstract

An analytical model is presented for the prediction of the amplification of compressional and shear waves produced by an explosion, or any other shock impact on the surface of a stratified soil deposit. This amplification is caused by multiple reflections of waves between the ground surface and an underlying parallel soil layer possessing different density and seismic velocity. The model developed may be easily applied for the protection of both buried and aboveground structures with the aid of suitable diagrams prepared in this work, which give, in a simple way, the enhancement factors by which particle velocities of direct waves should be multiplied to estimate the resultant particle velocities. The soil parameters that are taken into account in the analytical model and its simplified graphical solution are density, attenuation factor, and compressional- and shear-wave propagation velocities for the first two soil layers. Other parameters encountered are depth of the top soil layer, depth of burial of the structure, horizontal distance of the structure from the source, and TNT equivalent of the source. The cube root scaling is considered for the attenuation of waves in soil with distance.