Numerical solution model for instability of underground cavity

Failure of soft soils like sandy media after underground opening, usually involve three dimensional stress conditions in the materials. Furthermore, the behavior and stability of complex ground commonly involve a number of behavioral components such as: elasticity, plasticity, shear hardening, strength deterioration and high potential shear band location etc.. However, to determine the stress conditions which govern fracture of intact materials, a general three dimensional failure criterion is required. In this paper, a multilaminate based model capable of predicting the failure specifications of granular soil on the basis of sliding mechanisms and elastic behavior of particles has been introduced. This model is able to present numerical distribution of plastic strain through even highly anisotropic medium. Active orientations regarding the plastic shear strain, thereafter, is clarified. The orientation takes priority in plastic strain will fail first. Constitutive formulation of multilaminate elasto-plasticity has been implemented in appropriate finite element formulation and a computer program is developed. The generalization of multilaminate framework for all gauss points through the medium leads the solution to clarify rational failure mechanism which may occur first.