This work aims to be a contribution for a better knowledge of anchored earth retaining structures, providing preliminary guidelines for their correct design, by establishing starting points. It also constitutes the introduction to a second paper in which an innovative solution for preliminary design is presented. Starting from an extensive parametric study using PLAXIS on a typical moderate to high strength soil, the study begins by evaluating the influence of parameters such as the excavation depth, the stiffness of the retaining wall and the anchors, the initial prestress, and the soil properties(stiffness, strength, coefficient of earth pressure at rest and bedrock depth). For each parameter influence laws are derived, which will allow the implementation of the simplified design method in a companion paper.