SUMMARY REPORT OF RESEARCH ON PERMANENT GROUND ANCHOR WALLS, VOLUME I: CURRENT PRACTICE AND LIMITING EQUILIBRIUM ANALYSES

Research directed toward improving the design and construction of permanent ground anchor walls is presented. The research focused on tiedback soldier beam walls for highway applications. These walls are generally less than 25 ft (7.62 m) high, and they are supported by one or two rows of permanent ground anchors. This volume is part of a four-volume report summarizing the research. It presents apparent earth pressure methods for determining the lateral earth load. Differences between anchored and braced walls are discussed. The limiting equilibrium bases for the apparent earth pressure diagrams are reviewed. Current force equilibrium methods (simple limiting equilibrium methods) for evaluating the external stability of an anchored wall are reviewed. A force equilibrium method is developed and used to illustrate how anchor position, soil strength and the location of the failure surface affect anchor load, and internal and external stability of a wall. The factor of safety inherent in the apparent earth pressure diagram is determined. Recommendations for using general purpose slope stability computer programs for determining lateral load and evaluating internal and external stability of an anchored wall are made.