Subsoils and Foundation Design in Richmond, VA

The engineering properties of the subsoil in Richmond, Va. are analyzed on the basis of laboratory tests of undisturbed samples. It is shown that the strength of the massive clay and sand-clay strata is several times greater than had been assumed because of the small standard penetration resistance and the soft consistency of spoon samples. Only locally, where some recent clay deposits are not preconsolidated by surface drying, it is considered essential that in the design of heavy buildings, problems involving total and differential settlements are taken into consideration. Representative examples of heavy-building foundations are studied and it is emphasized that the driving of long piles through sensitive clay soils may not only be unnecessary but may result in unforseen difficulties.