Abstract
The present practice of reporting site investigations in areas of cohesionless soils, for roads, railways and canals in particular, is to produce a large number of particle size distribution curves. The value and meaning of such information is limited. To the Client it demonstrates that trial pits were dug and the soil was sieved, whilst to most engineers a well graded material signifies high stability and a uniformly graded one, low stability. This thesis examines cohesionless soil as a particulate system with the object of establishing a method of interpreting, in an engineering context, a particle size distribution; the simplest test carried out in routine site investigations. Fundamental to a particulate system is the interaction of its particles and this is dependent upon their packing. Of the many variables which govern packing the two primary parameters, that of particle shape and size distribution are discussed in detail and their influence upon shear strength considered. Using published results of porosity, shape and particle size distribution a simplified method of determining the minimum porosity of a cohesionless soil has been developed. It is concluded that this parameter can be successfully employed to classify cohesionless soil numerically and recommended that it serve as a basis for communication between Engineers.