Measuring the Structure of Mixed-Grain-Size Sediment Beds

A new sampling technique called wax coring is presented in this paper that enables the determination of the composition of the surface and subsurface of a sediment bed formed during flume experiments. A wax-impregnated circular core is removed from the bed and melted in a series of well-defined layers that are then sieved separately to provide data describing the variation with depth of the particle-size distribution. The volumetric equivalence of the grain-size distribution obtained for an internal layer is demonstrated theoretically and empirical data are obtained concerning the active layer concept that is often used in the modeling of mixed-grain-size sediment transport.