Centrifuge modeling of geotextile reinforced cohesive soil retaining systems.

摘要

Sixty reduced scale model walls, slopes, and embankments were built on weak, firm, and rigid foundations, using kaolin as the cohesive soil reinforced with a non-woven geotextile simulant, and loaded to failure under increasing self-weight in the geotechnical centrifuge. The objective was to gain insight into the mechanisms of failure in these reinforced retaining systems as they are affected by foundation rigidity, slope inclination, length of reinforcement, and lime-treated backfill. This study identified three major failure mechanisms for structures on competent foundations which were overturning, rotational sliding, and planar sliding. In all cases failure of geotextiles occurred by rupture of the reinforcement and reinforcement pullout was not occurred. Models on firm foundations tend to have a better performance than models built on rigid foundations. The positions of slip surfaces were influenced by a number of factors including: rigidity of the foundation, length and strength of reinforcement, and the properties of the backfill. Addition of lime to the backfill increased the failure height, changed the mode of failure, and changed the otherwise ductile and flexible structure to a brittle and rigid system with sudden failure. Different non-uniform reinforcement configurations were investigated in this study. It was observed that cracking has a significant role in the long-term behavior of cohesive soil structures. Stability analyses were performed using a limit equilibrium analysis using simplified Bishop method. In an overwhelming number of cases, safety factors were very close to one.