Experimental and Coupled Eulerian–Lagrangian Numerical Analyses of the Pullout Behavior of a Bearing Bar Reinforcement System

Abstract

In recent years, there has been a re-emerging interest in using inextensible reinforcement systems in reinforced earth structures. Regarding the pullout mechanism, optimum arrangements of inextensible reinforcement systems with bearing members are determined primarily via cumbersome large-scale experimental tests. An alternative approach to obtain the optimum arrangement of such reinforcements is numerical analysis. However, a convergent solution cannot be achieved via classical finite-element methods due to contact problems and mesh distortions. Moreover, common constitutive models cannot capture the primary pullout mechanism of inextensible reinforcements with bearing members. This study evaluated the primary pullout mechanism of a novel inextensible reinforcement system with bearing members, called the bearing bar reinforcement system, via large-scale monotonic pullout tests. In addition, the conducted pullout tests were simulated via a coupled Eulerian–Lagrangian (CEL) numerical approach with an advanced constitutive model. The agreement between the experimental and numerical results was good. This indicates that the numerical analysis can capture the main pullout mechanism of a reinforcement with a complex contact problem. The numerical analyses suggest that a spacing-to-height ratio of 10 is the optimal design in the sandy soil utilized in this study, because it ensures no interference between transversal elements. Generally, transverse elements with an optimum arrangement should be installed in the resistant zone (at the back of the maximum tension plane) for economic and engineering purposes. In practice, the pullout failure criterion is governed by a shallow depth (typically less than 3 m) because there is a negligible embedded length in the resistant zone. Thus, the optimum arrangement of the bearing bar system resulting from the short height of the transverse elements (h) can be employed in this zone. However, the rupture failure criterion is governed by greater depths. An optimum arrangement of the bearing bar system can be created by increasing the height (h) and, in turn, the spacing (S) of the transverse elements in such areas. In summary, the appropriate spacing-to-height ratio of transverse members with the optimum arrangement can be employed in practice based on peak pullout forces in reinforcements, which depend upon the embedded length and the horizontal and vertical spacings of the reinforcements.