Performance of Two Anchored Walls Under Cut and Fill Construction Sequences

Abstract

Tieback walls are typically designed using apparent earth pressures that are obtained initially by back-calculating earth pressures from measured support loads for excavation only. For construction activities involving both excavation and backfilling aspects, the use of apparent earth pressures might not be adequate. This paper investigates the performance of two tieback walls constructed using a combination of fill and cut construction sequences. Results obtained from data collected using load cells and strain gages along with the soldier piles of both walls, show the correlation of axial loads and bending moments to construction activities. Results show that some load is transferred to the soldier piles during anchor installation, despite using steel casings to prevent this action. Backfilling behind the wall created significant curvature in the soldier piles based on the measured bending moments. Moreover, results evidence that the apparent earth pressure does not reflect the observed bending moments in the walls. However, a beam model including lateral displacement is presented to represent the measured response in both walls. The results unveil differences in anchor loads estimations, evaluates the appropriateness of apparent earth pressures for the design of tieback walls and provides design recommendations.