MODIFIED FAILURE CRITERIA FOR SANDS

The note presents an analysis of experimental data to modify the extended tresca and extending Von Mise's failure criteria for sands and validates the results by means of available published data of principle stresses at failure in a general triaxial stress system. New techniques for testing soils in a general stress state have been developed which makes it worthwhile to find how the influence of the intermediate principal stress can be taken into account in the theories of failure so that a good agreement with experimental results is obtained. The values of the angle of shearing resistance predicted by the three theories have been compared by Bishop and expressions have been formulated; the strengths are assumed to be the same in extension and compression so that are intermediate values the actual yield surface circumscribes the Mohr-Coulomb hexagon touching its extension and compression points. /TRRL/