Reliability-Based Determination of the Coefficients of Lateral Earth Pressure on Retaining Walls Subjected to Seismic Loading

The active and passive lateral earth pressures against retaining walls under seismic loading are investigated, taking into consideration the variations of internal friction angle phi and seismic effect represented by the seismic angle theta. This study basically involves the computation of the active and passive lateral earth pressure coefficients, k(ae) and k(pe), and their coefficients of variation, cov(k(ae)) and cov(k(pe)), using a first order Taylor's series expansion. The concept of extreme value distributions (maxima and minima) is utilized for evaluating the reliability of these earth pressure coefficients. Design charts are developed for a wide range of granular soils. Examples illustrating the design method based on the usage of the reliability of these coefficients are also presented. Values of load factor utilized in the conventional deterministic approach are correlated with reliability levels; the load factor values vary depending on the importance of the structure and the variations of the design input values as contrasted to the constant value of load factor used in the conventional deterministic approach.