Passive earth pressures in the presence of hydraulic gradients

The paper describes a variational approach applied to the limit equilibrium method for calculating the effective passive pressures of cohesionless soi l, taking into consideration the seepage flow. It is shown that in the gene ral case of non-homogeneous and non-isotropic hydraulic properties of the s oil medium, the shape of the slip surface which verifies the three limiting equilibrium equations of the soil mass at failure is a log-spiral, It is a lso shown that the passive earth pressure calculation is independent of the normal stress distribution along this surface. The variational limit equil ibrium method is equivalent to the upper bound method in limit analysis for a rotational log-spiral mechanism. Numerical results of the coefficients o f passive earth pressures in the presence of seepage flow are presented and discussed.