System reliability assessment on deep braced excavation adjacent to an existing upper slope in mountainous terrain: a case study

Abstract

Due to rapid urbanization, the land resources available for construction are becoming increasingly scarce in many built-up environments, especially for infrastructure development in mountainous terrain. For deep excavations developed for basements of high-rise buildings in cities with mountainous terrains, the excavation activities may have an influence on the stability or performance of existing nearby upper slopes. Based on a case study in Chongqing, this paper numerically investigates the effects of the excavation geometry, the retaining wall system stiffness and the distance between the excavation and slope on the performances including the global factor of safety and retaining wall deflection of the excavation-slope system. Subsequently, simplified ultimate and serviceability limit state response surface models have been developed and implemented into the First-Order Reliability Method to determine the probability that the ultimate or serviceability limit state is exceeded by performing probabilistic analysis on the global factor of safety through setting the threshold maximum wall deflection as an optimization constraint.