Case history of geosynthetic reinforced segmental retaining wall failure

A geosynthetic reinforced segmental retaining wall was collapsed during a monsoon season in Korea, three months after the completion of wall construction. The circular type global slope failure was the dominant failure mode. The as-built design was examined for its appropriateness in meeting the current design requirements and the global slope stability. A comprehensive stress-pore pressure-coupled finite-element analysis was additionally conducted with due consideration of both positive and negative pore pressures in saturated and unsaturated zones. A number of relevant tests were also carried out on the backfill and the reinforcement collected from the site. The investigation revealed among other things that the inappropriate design and the low-quality backfill were mainly responsible for the wall failure, although the primary triggering factor was the rainfall infiltration. The results of the stress-pore pressure-coupled finite-element analysis provided sound evidences as to the wall performance over the rainfall period, supporting the field observation. Practical implications of the findings from this study are also discussed in view of reinforced wall design.