INSIGHT TO FAILURE MECHANISMS OF CAISSON FOUNDATIONS UNDER COMBINED LOADING: A MACRO-ELEMENT APPROACH

The undrained response of massive caisson foundations to combined horizontal, vertical and moment loading is investigated through a series of three-dimensional finite element analyses. The ultimate limit states are presented by failure envelopes in normalized form. The effects of embedment ratio and vertical load on the bearing capacity are investigated in detail. Closed-form expressions are proposed for (a) the yield surface in M-Q-N space, and (b) the lateral capacity under pure horizontal and moment loading. Finally, the use of an associated flow rule to define the plastic deformation of the caisson at near failure conditions is parametrically examined. The results of the analysis could serve as a basis for a macro-element approach.

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