Experimental, analytical, and finite element assessment of the shear strength of concrete‐rock interfaces at different scales

Abstract

This paper presents an original analytical approach to assess the shear strength of concrete‐rock interfaces while accounting for the effects of scale, roughness and matching conditions. The technique proposed is based on experimental data obtained from small core samples extracted from existing dam sites, with diameters varying from 83 to 145 mm, and larger rectangular samples with side lengths comprised between 320 and 492 mm. The predictions of the analytical formulation are validated against results of direct shear tests, as well as 3D nonlinear finite element simulations. Sensitivity analyses are conducted to evaluate the influence of roughness and matching conditions on the shear behavior of concrete‐rock contacts at different scales. The main results show that: (i) roughness inhomogeneity is one of the main causes of scale effects on the shear strength of concrete‐rock interfaces; (ii) contact geometries proportional in both length and height are expected to present quite similar shear strengths; and (iii) geometry matching conditions must be accounted for as they might be the source of scale effects affecting the evaluation of the shear strength at concrete‐rock interfaces. New equations are also proposed to suggest values of apparent cohesion and friction angle for concrete‐rock contacts.

Numerical Analysis for Shear Behavior of Binary Interfaces under Different Bonded Conditions

“…Consequently, there is also an abundance of binary structural surfaces in geotechnical engineering, such as rock-concrete interfaces, whose mechanical properties are key determinants of the effectiveness of many reinforcement measures [6]. Therefore, a huge number of scholars at home and abroad have carried out relevant research on binary interfaces from experiments, numerical simulations and theoretical analysis [7].…”