Coupling DiscontinuousContinuous Simulation of Reinforced Soil Walls with Flexible/Rigid Facings on Soft Foundation

Abstract:

A discontinuous and continuous coupling numerical model was established for a reinforced soil walls with flexible/rigid facings on soft soil based on centrifuge modelling. In the numerical model, the wall and soft foundation were simulated using particle flow code (PFC) and fast lagrangian code (FLAC), respectively. The behavior as well as the internal and external stability of the wall was investigated. The results show that the numerical results such as the settlement of retaining wall, the horizontal displacement of wall facing, the vertical earth pressure at wall base, and the moment of rigid wall facing are in good agreement with the measured results in the centrifuge modelling. The wall suffers a large and differential settlement due to its own weight and the surcharge loading, but the overall structure is still stable, indicating that the reinforced wall with flexible/rigid facings can well adapt to the soft foundation. The stress concentration is observed at the end of the anchor at selfweight loading and surcharge loading, leading to the maximum settlement in the foundation. At surcharge loading, the rigid wall at the middle bears a tensile force outside the wall and the maximum bending moment, whereas the rigid wall near the bottom and the top bears a tensile force inside the wall and the comparatively low bending moment. The reinforced wall with flexible/rigid facings on soft foundation generally suffers from the external stability of the deepseated failure. The failure surface is composed of the Rankine failure surface in the unreinforced soil and a circular failure surface in the soft foundation. The internal stability of the walls with flexible/rigid facings indicates that the reinforcements are fractured from the bottom to the top of the wall in sequence following the slip failure of soft foundation, forming a Rankine’s failure surface along the end of the anchors.