SEISMIC STABILITY OF SUBMARINE CLAY SLOPES BASED ON UPPER BOUND APPROACH

The upper bound method of limit analysis has received extensive attention in the stability assessment of submarine slopes. However, the method has not take into account the seismic load and the possible local failure mechanism of multi-layered submarine slopes. Based on the upper bound theorem, we derive the equilibrium equation of power dissipation and internal energy dissipation rate of multi-layered submarine slopes under horizontal pseudo-static earthquake load. Combined with the strength reduction technique and the optimization method, we solve the global and local factors of safety of submarine slopes under different horizontal seismic coefficients, and successfully search the local sliding surfaces of multi-layered submarine slope. The analyses of typical examples verify the effectiveness of the proposed method. On this basis, we discuss the global and local stability of submarine slopes with two typical combined soil layers under different earthquake conditions. By comparing with the numerical solution, we can accurately evaluate the stability of submarine slopes and effectively predict the position of critical slip surfaces. Finally, the improved method is applied to one case of submarine slope.