ABSTRACT
Developments in theoretical soil plasticity in the early 1960s led to study of flows of particulate materials, powders, sands, crushed rock, and so forth. While traditional applications of plasticity theory to retaining walls and foundations had stability as a primary objective, the opposite result – flow –is the desirable outcome in application to chutes, bins, silos, and ore passes. Many early sand models used horizontal layers that while qualitative clearly demonstrated the development of velocity discontinuities. Many industrial facilities for handling particulate materials are terminated with hoppers that have sloping walls intended to aid discharge. Although physical data from experiments as done on sand models remains essential to progress and, indeed, has given rise to a sub-discipline of the physics of granular flows, modern computer methods provide far superior experimental platforms for study of particulate materials.
