PLANE SHEAR-WAVES IN A FULLY SATURATED GRANULAR MEDIUM WITH VELOCITY AND STRESS CONTROLLED BOUNDARY-CONDITIONS

A one-dimensional system describing small shearing disturbances in a s emi-infinite, fully saturated granular medium is studied. The system i s fully non-linear as a result of the incrementally non-linear constit utive law for the material. In particular, there are two different wav e speeds corresponding to loading or unloading of the material. Global solutions are constructed with boundary data consisting of a single p ulse in either velocity or stress. In the case of velocity controlled boundary conditions, the solution is a traveling pulse of increasing k inetic energy which eventually unloads the material, regardless of whe ther the initial pulse loads or unloads. The solution with stress cont rolled boundary conditions has these Features only if the initial stre ss pulse unloads the material. If the initial stress pulse is loading then the solution is a slowly traveling pulse of decreasing kinetic en ergy which is also loading. (C) 1997 Elsevier Science Ltd.