Tunnel Face Stability Considering the Influence of Excess Slurry Pressure

With excess slurry pressures exerted on the tunnel face, particles tend to infiltrate into soil in front of tunnel. There will be pore pressure ahead case infiltration, leading an impairment supporting effect contributed by pressure. Corresponding three infiltration scenarios distinguished forms filter cake, different transfer models are employed describe distribution. Using kinematic approach limit analysis and numerically simulated seepage field, study face stability under cases is extended employing a 3D discretization-based failure mechanism. In addition, two simple empirical formulas describing distributions above advance established verified. Combined with dichotomy method strength reduction method, safety factors yielding rigorous upper-bound solutions obtained optimization. The proposed validated comparative analysis. developed framework allows considering influence whole mechanism three-dimensional characteristics seepage. A parameter performed pressure, hydraulic conditions, properties, drop coefficient. results show that steady-state flow model leads much more conservative than full-membrane model. factor increases increasing decreasing present work provides effective quickly assess tunnels cake scenarios.