Abstarct: The increase of construction density in urban environments has greatly highlighted the importance of protection of excavations and adjacent structures and selection of an appropriate retaining system to protect excavations. This research discussed the system of a propped diaphragm retaining wall. Such systems are highly considered, because nailing and anchoring systems have many legal problems in our country in terms of entering the neighboring ground. A diaphragm retaining wall is of the flexible walls, which is considered for deep excavations due to ease of implementation and cost-effectiveness; however, classical analytical methods are not effective for these types of combined retaining systems and they fail to predict their behavior correctly. With the development of numerical methods including the finite element method (FEM), it is now possible to have a further accurate prediction of the behavior of such retaining structures. This research used Abaqus finite element program for modeling soil behavior, wall, and propped wall and examined a propped flexible retaining wall in static and dynamic conditions for two 6- and 12-storey structures beside excavations. The comparison of the results obtained from finite element analysis (FEA) and classic methods, concerning lateral pressure, indicated lower values for classical methods than numerical analysis. For instance, Tschebotarioff theory and Peck theory showed 16% and 14% lower values than Abaqus analysis in static conditions and in case of lack of structure respectively. Moreover, it was specified that because of excessive displacement during earthquake, this system lacks the required efficiency and it is better to be used as a temporary system for retaining structures.