Numerical modelling of dam using the modified Cam Clay extended to the unsaturated condition

In this paper, a finite-element analysis of a zoned earth-dam is presented, in which the mechanical behaviour of the core material is described via an extension of the classical modified Cam-Clay to the partially saturated range as proposed by Jommi and Di Prisco. In this approach, the effects of partial saturation are accounted by using a thermodynamically consistent expression for “effective stress” (similar to the expression proposed by Bishop), allowing the evolution of hardening to depend on the variation of the degree of saturation Sr and introducing a constitutive equation relating the changes in Sr to the changes in suction s. this equation models the water retention curve. The constitutive model has been implemented in the FE code ABAQUS. The dam construction and the first phase of impounding are simulated. They are a firs attempt in applying the Cam-Clay extension to a real engineering problem.