The design of underground spaces is mainly carried out using empirical, analytical, and numerical methods. The convergence confinement method (CCM) is an analytical technique that is widely utilized in analyzing the stability of underground spaces. However, the main challenge in the stability analysis is the selection of an accurate constitutive model for rock mass, and particularly, its post-f...

Earlier results [1,2]2 on safe loads for a Prandtl-Reuss material subject to surface tractions or displacements which increase in ratio are here extended to any perfectly plastic material and any history of loading.

We study numerically a simple network model which is an electrical analog of a perfectly plastic disordered medium. For a uniform random distribution of local maximum current, (e.g. yield stress), we study the evolution of the properties of the system as a function of the number of elements which reached the plastic limit. It is shown that the macroscopic yield point can be interpreted as a cri...