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Characterize the variation in the mechanical characteristics of stratified soil layers during an earthquake based on their level of shear deformation.

To do this, equivalent linear characteristics are determined by an iterative procedure for each of these soil layers, equivalent linear characteristics adjusted from the curves for reducing the shear modulus and increasing the hysteretic damping as a function of the shear deformation. This procedure is generally based on a laminate floor column model with two different types of modeling:

• 2D in plane deformations meshed by horizontal layers, subjected to a training acceleration with periodicity condition between the left and the right face and absorbent condition at the base. This modeling also allows water pressures to be taken into account in a simplified way by the Byrne method.

• 3D meshed by horizontal layers and subjected to training acceleration in the 3 directions X, Y and Z, with penalization stiffness at the lateral edges to ensure the same dynamic behavior in both horizontal directions and an absorbent condition at the base.

The DEFI_SOL_EQUI command makes it possible to produce a table containing information necessary for the description of a soil file for the MISS3D software.