Investigation of corroded stainless steel reinforcing elements in spent oil shale backfill

Abstract

Excavations for a new service installation in Lindsay Road, Edinburgh, revealed that the ferritic stainless steel reinforcements of the supporting reinforced earth retaining wall were, in parts, severely corroded. This paper presents the findings of an investigation into the cause of the deterioration of the wall. The results of chemical tests undertaken on the backfill indicate that the material was most likely unsuitable for the construction of reinforced earth structures with any of the types of metallic, reinforcement that are, or have been, commonly used. Ferritic stainless steels are now generally considered to be unsuitable for use in reinforced earth structures regardless of backfill type. Indeed, the use of the materials for reinforcements ceased within a few years of the construction of the wall at Lindsay Road. Surveys of the alignments of the wall have also been conducted. The surveys of the wall indicated that there was no measurable movement prior to demolition.