Complex probabilistic approaches for the analysis of structures have been increasing in interest and application both in the area of research and in practice in order to provide a more uniform level of reliability. Also, the design codes, such as the Eurocodes, are developing provisions to address reliability-based design methods in more detail. Moreover, FEM is very popular nowadays using advanced constitutive laws and modelling staged construction. This is especially important for geotechnical structures, such as retaining walls for deep excavations, for which soil-structure interaction is a complex mechanism. The paper will present a full probabilistic analysis performed for a real case temporary retaining wall of a deep excavation. The probabilistic analysis was combined with FEM using advanced constitutive models. The objective is to demonstrate the feasibility of a full probabilistic analysis, using the current advanced design methods, and to assess the reliability produced by Eurocode designs. The main uncertainties were modelled as random variables and the limit state verification was expressed in terms of reliability index or, equivalently, the probability of failure for SLS and ULS verification. The procedure of coupling probabilistic analysis using Probabilistic Toolkit reliability software with FEM Plaxis 2D commercial software for geotechnical analysis is given in detail while emphasizing some critical aspects in relation with these types of combined analyses and reliability concepts. At last, some issues related to the provisions of the current design codes are presented and discussed in order to facilitate the implementation of reliability-based design, either through probabilistic methods or by partial factors.

Common practice for design of retaining walls for deep excavations is by using characteristic values for geotechnical parameters—as a cautious estimate—for Serviceability Limit State (SLS) and combined with partial factors for Ultimate Limit State (ULS), as indicated in the current design codes such as the Eurocodes. However, more complex probabilistic approaches are increasing in application in order to provide a more uniform level of reliability, thus reducing the cost of the investment or the risk, or both. Also, in terms of tools and methods for performing the calculations, the Finite Element Method (FEM) is very popular nowadays due accessible computers power and user-friendly specialized software which can provide more realistic model, with affordable calculation effort. The present paper presents a case study of applied full probabilistic analysis of a retaining wall for real project deep excavation in Bucharest city, Romania, by FEM calculation in Plaxis 2D software coupled with Probabilistic Toolkit (PTK) software for reliability calculation. The limit function is set on a target value for the displacements of the retaining wall to allow to design for the SLS, since this is in many cases the governing state for deep excavations in urban areas. Different probability distributions are used for assessing the statistics of the geotechnical parameters and the reliability results obtained through these are discussed. Also, a discussion is made on the necessity of including more specific target reliability values for SLS verification and especially for temporary structures in the design codes.