Based on the upper-bound approach of limit analysis and the strength reduction technique

the equation for expressing the critical state of slope stabilized by a row of piles is formulated and is employed to determine the lateral limit effective earth pressure and its corresponding critical failure surface for a given slope subjected to pore water pressure. The presence of pore water can be embodied through work terms in the energy balance equation

and water pressure is considered as an external force similar to gravity and surface tractions. Furthermore

the governing equation of deflection for stabilizing pile is built based on the obtained dimensionless lateral limit effective earth pressure

and the numerical algorithm using finite-difference method is developed to numerically solve the partial differential equation. Finally

numerical computations are made to examine the effect of pore water pressure on optimum location of pile placement and the reinforced force supplied by piles with a typical example slope.