A theory of the kinematics of ideal soils under plane strain conditions

Abstract A n examination of existing theories of the kinematics of ideal soils suggests that none of these yet provide a really satisfactory basis for further developments of the theory. A theory is proposed, for plane deformations of ideal soils, which is based on the postulates of material isotropy, soil incompressibility, and the idea that deformation occurs by shear on certain critical planes. It is found as a natural consequence of these assumptions that the strain-rate in the soil is dependent on the stress-rate as well as on the stress. The theory is applied to the problem of indentation of a semi-infinite mass of soil by a flat smooth rigid punch.