Abstract：Based on the kinematics approach of limit analysis and the concept of shear strength reduction，the equation for expressing the limit-equilibrium state is formulated and is employed to determine the factor of safety and its corresponding critical failure mechanism for a given slope. Through numerical analysis of typical examples and comparisons with the results computed by using both limit equilibrium method and finite element method，the reasonability and applicability of the proposed procedure are verified. Then，for the slopes whose factors of safety cannot fulfill the requirement of overall stability for the given loading condition，the stabilizing pile is considered for reinforcement of the slope. The upper-bound theorem of limit analysis is employed once again for establishing the limit-equilibrium equations of the slope reinforced by stabilizing pile in which the mobilized strength parameters are given by the actual strength parameters with a reduction by the desirable overall factor of safety. The lateral effective earth pressure acting on the pile can be chosen as the objective function；the mathematical optimization technique is utilized to define the critical state. The dimensionless critical overall lateral effective earth pressure is used in the structural simplified design of pile. Finally，the principle of maximum and minimum values is employed to optimize the most rational location of piles within slope. Based on comparative studies for different combinations of related parameters，the effects of some factors on the stabilizing forces which are required to increase the factor of safety to a desired value are examined systematically.
