A simple probabilistic approach for internal stability analysis and design of geosynthetic reinforced soil walls

This paper explains simple probabilistic analysis and design for tensile strength and pullout internal stability limit states for geosynthetic reinforced soil walls. The general approach uses a closed-form solution for reliability index which is easily implemented in a spreadsheet and thus eliminates the need for Monte Carlo simulation. A novel feature of the formulation is that it includes uncertainty in the calculation of nominal values which is consistent with the notion of level of understanding that appears in the Canadian Highway Bridge Design Code, and variability in the underlying accuracy of the load and resistance models that appear in each limit state equation using bias statistics. Here, bias is the ratio of observed value to predicted value using closed-form solutions for load and resistance terms. A design example based on a constructed geogrid reinforced soil wall is used to demonstrate the general approach.