Rigid-plastic modeling approach to critical deformation

It is very important in tunnel planning and construction to have the tunnel stability estimate. The strength and deformation estimation criteria help to reach the point. The deformation criterion is a ratio of the maximum deformation of the tunnel contour, that is either calculated or measured, to the maximum allowable (limit) deformation, that is determined with the use of the known equations, for instance, Sakurai’s equation. This paper describes a new rigid-plastic model approach to determining the limit deformation of rocks and compares the new modeling results with the other obtained from the known limit deformation equations.