When the ground destroys, shear strain is concentrated in the limited domain, and slide plane (shear zone) occurs.
Before its destruction, the slide plane (shear zone) gradually grows up and becomes a large-scale sliding.
A big shear distortion in the Footing end is the beginning of the slide
plane (shear zone), and the Drucker-Prager model is a suitable constitutive
relation.
The Drucker-Prager model is proved to reproduce an actual behavior of soil
structure in the field of the finite element method, and could be applied
to analyze the soil behavior beneath the Footing.
Recently, in contrast, the particle method has been successfully applied
to analyze the soil behavior under a large displacement and a large strain.
The results of SPH(Smoothed Particle Hydrodynamics) is compared with the result of a non-linear finite element method.
