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Failure mechanisms of geosynthetic-reinforced wall with modular blocks: from centrifuge test to numerical analysis

The use of geosynthetics as structural elements in earthen wall stabilization is actually worldwide diffused and evaluation of reinforced soil retaining wall performance has rapidly become a fundamental problem in engineering works. Advanced numerical analysis in conjunction with experimental tests are usually required to perform accurate studies on the various failure mechanisms, as global instability, breakage of the reinforcements and pull-out failure. Built from results obtained on previous laboratory small-scale tests and preliminary numerical analysis, a real-scale finite element model of geosynthetic-reinforced soil retaining wall has been created mainly to investigate the structure performance respect to internal failure mechanisms, which study was not accounted during the experimental campaign conducted through centrifuge testing. For this purpose, geogrid tensile strength and soil-geogrid strength interface have been progressively, and separately, reduced until respective failures occur; afterwards, at different reduction degrees, safety analysis have been conducted in order to evaluate the residual strength state. This study aims to underline the influence of reinforcement resistance and soil-geogrid interaction parameters on internal stability evaluation. Furthermore, prelaminar indication on near-collapse conditions, in reference to breakage of the reinforcements and pull-out failure mechanisms, are finally provided.