The research is focused on the analysis of passive piles, i.e. piles subjected to external soil movements which causes pile stressing. A typical example of passive piles is represented by piles used to stabilize unstable slopes. The study is a very complex and challenging task because it involves a complicated soil-structure interaction mechanism which depends on the assumed soil movement distribution. As far as passive pile design is concerned some simplified models are analyzed based on different hypotheses on pile deformability (rigid or flexible piles), soil conditions (fully elastic, fully plastic or elastic-plastic) and distribution of soil parameters with depth (homogeneous cohesive or non cohesive soil, two-layer soil, etc). The research also involves the implementation of specific computer programs in Fortran language required to analyze both a passive pile embedded in a given soil stratigrafy and a generic slope stabilized with a row of piles using the traditional limit equilibrium methods modified to account for the piles contribute.