Analyses on face stability of shallow tunnel considering different constitutive models

Based on the finite element limit analysis method, stability of face in case active failure under three constitutive models, Mohr-Coulomb model (MC), modified Cambridge (MCC) and Drucker-Prager (DP), were analyzed. The ultimate support pressure influence factors such as different burial depth ratios ( C/D ), cohesion c ) friction angle φ MC are also discussed. results show that safety factor obtained by MCC same is always smaller than model, difference largest when there no pressure. As increases, it will gradually approach model. When small, DP larger but large, final tends to be stable. It necessary select an appropriate according rock masses practical engineering. self-stabilizing performance not affected , increase with decrease linearly cohesion, angle. greatly hardly .