DIRECT SOLUTION OF PLASTICITY PROBLEMS IN SOILS BY THE METHOD OF CHARACTERISTICS.

The method of characteristics is well established as a direct method of solving for the stresses in plasticity deforming soils under conditions of plane strain. The application of similar methods to problems of axial symmetry, and to soils with non-homogeneous properties is described and some illustrative examples given. The method of characteristics may also be used for the solution of the plastic displacement equations, although the exact form which these equations should take is still a matter of controversy. Illustrations are given of displacement calculations using the simplifying assumptions either of an associated flow rule (which is unrealistic for a frictional material) or using a fixed rotation term (which, although it has no physical justification, leads to realistic displacement fields). Refs