LIMIT LOAD IN TRANSLATIONAL FAILURE MECHANISMS FOR ASSOCIATIVE AND NONASSOCIATIVE MATERIALS

Translational failure mechanisms for estimation of the limit load in g eotechnical boundary-value problems are considered. The equivalence of the energy balance approach and the equilibrium of forces approach fo r limit load evaluation in this type of failure mechanism is studied i n detail. The soils are modelled as rigid-perfectly plastic materials with flow rules associative and non-associative to a linear Mohr-Coulo mb yield condition. It is demonstrated that for non-associative materi als with a coaxial flow rule, the limit load in translational failure mechanisms corresponds to a fully developed residual strength due to n on-associativeness, and is lower than the limit load for the associati ve material. However, the limit load for nonassociative materials with a non-coaxial flow rule may be the same as for the associative materi al. Implications for the interpretation of one of the limit equilibriu m methods are discussed.