Seismic technique to determine the allowable bearing pressure for shallow foundations in soils and rocks

Abstract

Based on a variety of case histories of site investigations, including extensive bore-hole data, laboratory testing and geophysical prospecting, an empirical formulation is proposed for the rapid determination of allowable bearing capacity of shallow foundations. The proposed expression consistently corroborates the results of the classical theory and is proven to be rapid and reliable. It consists of only two soil parameters, namely, the in situ measured shear wave velocity, and the unit weight. The unit weight may be also determined with sufficient accuracy by means of another empirical expression using the P-wave velocity. It is indicated that once the shear and P-wave velocities are measured in situ by an appropriate geophysical survey, the allowable bearing capacity as well as the coefficient of subgrade reaction and many other elasticity parameters may be determined rapidly and reliably through a single step operation, not only for soils, but also for rock formations. Such an innovative approach, using the seismic wave velocities only, is considerably cost- and time-saving in practice.