ALLOWABLE BEARING PRESSURE IN SOILS AND ROCKS THROUGH DYNAMIC WAVE VELOCITIES

Abstract

Based on a variety of case histories of site investigations, including extensive bore hole data, laboratory testing and geophysical prospecting at more than 550 construction sites, an empirical formulation is proposed for the rapid determination of allowable bearing pressure of shallow foundations. The proposed expression corroborates consistently with the results of the classical theory and is proven to be rapid and reliable. Plate load tests have also been carried out at three different sites to further confirm the validity of the proposed method. It consists of only two soil parameters, namely, the in situ measured shear wave velocity and the unit weight. The unit weight may also be determined with sufficient accuracy by means of another empirical expression proposed, 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 pressure as well as the coefficient of subgrade reaction and many other elasticity parameters may be determined rapidly and reliably, not only for soils but also for rocks.