Model Behavior of Prestressed Tie‐back

Abstract

Tie‐back walls are frequently used presently for the support of deep excavations, yet soil‐structure interaction under “service” conditions is not really understood. This study is an attempt to analyze the problem using the results of experimental work by the writer. Soil and wall movements, variations in anchor prestress, as well as sand stresses on the wall were measured on a small scale physical model. Numerical parametric analyses of soil‐structure interaction based on a Winkler model were also made by varying soil stiffness, soil properties, and anchor prestress values to fit the model tests. Results were subsequently extrapolated to real size. It was shown that the soilwall‐anchor interaction was profoundly influenced by an increase in the anchor prestress, which generally led to a large reduction of the associated tie‐back displacements. This should be attributed to the force equilibrium on the wall, which was shown to differ markedly from the one used by conventional limit equilibrium design.