there are various parameters that affect stability and expansion of failure zones in under pressure tunnels. among the important parameters that affect failure zones around the tunnels are cohesion and internal friction angle of the rock mass. in addition, the cross sectional shape is the considerable point in failure distribution around the tunnels. the stress analysis method is one of the app...

Abstract We discuss some frequency-domain criteria for the exponential stability of nonlinear feedback systems based on Popov’s hyperstability theorem. The main results are new bounds convergence rates perturbations damped harmonic oscillator, including Hessian-damped case, when satisfy certain sectoriality or convexity hypotheses. also include a simplified proof theorem in its general form, wh...