The Wall That Moved

A multi-row anchored soldier piled wall was designed to support the sides of a deep basement excavation adjacent to a railway embankment. As part of the approval process, the contractor’s consultants had to carry out detailed analyses to demonstrate the suitability of the wall and agreed to a monitoring plan of regular site inspections by a geotechnical engineer including regular surveying of the wall to check on the wall’s performance during the construction phase. Construction began, the soldier piles were installed, and excavation and anchoring commenced in stages. Surveying of the wall also started, but the contractor neglected to get the geotechnical inspections required by the monitoring plan. All seems to be going well until unacceptable lateral movements of the retaining wall were detected from the survey. This paper describes the design of the wall, a review of the construction phase information and offers an explanation for the higher than expected wall movements.