6. Illustrations and validations

Typical soil mechanics problems are analyzed next to illustrate and validate the program.

6.1. Initial state analysis

The geotechnical engineer is often confronted with a site with existing constructions. An exact assessement of the initial state requires the simulation of the loading history of the site but this would require a considerable amount of computations. An alternative and usually sufficient evaluation of the stress state is obtained by superposing gravity and the stress state induced by gravity considered as initial stress state. The result is a zero-deformation state associated with the gravity induced stress state. Initial loads independent gravity can be accounted for in a similar way.

An illustration of initial state analysis is given next. The initial state analysis is performed on a site with two existing buildings, the goal is to evaluate if additional stories can be added.

The value taken by the failure criterion for the present stress state is representative of the amplitude of the stress state on the site with respect to failure. The value of the stress-level must be <= 1 otherwise the stress state would be outside of the plastic criterion which limites allowable stress states, a stress-level = 1 corresponds to a plastic state and a stress-level < 1 to an elastic state.