Case History-Based Comparative Analysis of Coupled and Uncoupled Approaches for Pile-Reinforced Slopes

This work provides a comparative analysis based on re-evaluating three case histories of pile-reinforced slopes. The evaluation is done by performing two- and three-dimensional finite element (coupled) and limit equilibrium plus laterally loaded pile response analysis (uncoupled) using calibrated cases originally evaluated by only one technique. The objective of this work is to assess the sensitivity of pile lateral displacement and pile structural demand (shear and bending) to analysis technique and dimensionality. Overall, for pile lateral displacement and bending moments, the results show good agreement between the analytical methods and the field condition. On the other hand, for the shear resistance, some differences are found among analytical results and the field condition. The zone below the sliding depth is the one with a higher disagreement between field conditions and analytical results. The differences can be related to rigid body assumptions for some methods when the critical surface is a zone and not a line. In general, both coupled and uncoupled methods, if performed correctly, are powerful tools for after-failure evaluations where calibration between analytical methods and instruments is possible. The current analytical methods for slope stability analysis are potent estimating tools for pile-reinforced slopes. Nevertheless, the agreement between analytical methods does not guarantee close agreement with the field condition. From the results, recommendations for the analysis and design of pile-reinforced slopes are given.