DISCRETE ELEMENT METHOD-BASED CHARACTERIZATION OF INTERFACE BOND BEHAVIOR OF GFRP TENDON EMBEDDED IN CEMENTED SOILS

The load-bearing performance of the reinforced cement-soil structure depends on the interface bond behavior of the reinforcement embedded in cement soils. This paper aims to investigate the mobilization mechanism of interface bond strength between the GFRP tendon and cemented soils. The element pullout test of GFRP tendon embedded in cement soil is modeled numerically using domestic matrix discrete element software MatDEM. First, the load-displacement curve obtained by the numerical simulation is compared with the experimental results to validate the reliability of the numerical modelling. Second, the evolution of the displacement field of the reinforcement-soil interface, the development of the shear band, and the evolution of the cementation failure are interpreted to characterize the interface bond-slip behavior of GFRP tendon embedded in cemented soils from the microscopic view. Lastly, the impact of rib geometric features on the interface bond-slip behavior is studied in parametric sensitivity analysis. The concluded remarks are obtained in this work as follows.(1)The tendons-soil interface experiences shear failure twice in the pullout process of GFRP tendon embedded in cemented soils corresponding to the pullout displacement of 4mm and 10mm, respectively. (2)The thickness of shear band and the number of particles in shear condition increase along with the development of pullout displacement. But the increasing trend slows down over the increasing interface slip. (3)The cementation failure of particles develops from the interface to the neighboring cemented soils radially over the increase of pullout displacement, and in a stagewise trend corresponding to that of the pullout load-displacement response. (4)The magnitude of rib spacing affects the pullout displacement corresponding to each characterizing load. The magnitude of rib height affects the magnitude of each characterizing load. There is an optimal rib height for a constant rib spacing which can mobilize to the largest extent the interface bond strength. The findings in this work can provide insights to the design practice of load-bearing interface for the reinforced cement-soil structures.