Reliability Based LRFD Approach for External Stability of Reinforced Soil Walls

摘要

The main objective of reinforced soil wall design is to ensure safety and performance requirements of a wall for target reliability levels. Analysis is conducted to evaluate the external stability of reinforced soil walls. As this must be accomplished under conditions of uncertainties associated with reinforced backfill, retained backfill, foundation soil and surcharge load acting on the wall, probabilistic analyses are necessary in the development of such reliability based design for external stability of reinforced soil wall. A methodology for developing load and resistance factor design guidelines for reinforced soil walls is outlined in this paper. The potential failure mechanisms considered in the analysis are sliding failure, eccentricity failure of resultant force (or overturning failure) and bearing capacity failure. A first order reliability method is used to determine appropriate ranges for the values of the load and resistance factors. Load and resistance factors needed to maintain the stability against three modes of failure by targeting component reliability indices of 2, 2.5, 3, 3.5 and 4 are obtained for various values of coefficients of variation of friction angle of backfill and foundation soil, distributed dead load surcharge, live load surcharge and cohesion of the foundation soil.