Mechanical Behavior of the Rock-Concrete Interface for a Bridge Anchorage Structure Using Discrete Element Method

Traditionally, the numerical simulation work of a bridge gravity anchorage structure is performed with a continuous method, such as the finite element method (FEM). However, since the rock mass and gravity anchorage structure are assumed to be continuous in the FEM, the interaction between the rock mass foundation and the concrete of the anchorage is not frequently considered. This paper aims to investigate the problem of the interaction between the rock mass foundation and the concrete of the anchorage. The discrete element method (DEM), which has been verified to be suitable for the modelling of contact problems of discrete blocks, is introduced in this paper to simulate the mechanical behavior of the rock-concrete system of the gravity anchorage structure and its rock mass foundation. Based on the in-situ scale model test for a bridge, the mechanical behavior of the rock-concrete interface was discussed with the DEM method. With the calibrated DEM model, the displacement of the foundation rock mass, contact stresses, and yield state on the rock-concrete interface were numerically investigated. The anti-sliding effect of the keyway and the step at the bottom of the gravity anchorage structure was analyzed. The results show that the anchorage deformation under the design conditions is basically characterized by the rigid rotation around the keyway of platform #2, and that such rotation subsequently affects the anti-shear capacity of the entire gravity anchorage to a large extent. The anchorage scale model could remain stable under the design lateral load such that the rock-concrete interface would remain intact and sufficient shear resistance could be provided by the keyway and steps.