Elastoplastic coupling analysis of high-strength concrete based on tests and the Mohr-Coulomb criterion

With the development of material technology, high-strength concrete has been widely used in immersed, underwater and deep-buried tunnels, which exhibit elastic, brittle and plastic states under various stress conditions. However, the research on constitutive models of high-strength concrete is insufficient, especially regarding the elastoplastic coupling properties. Therefore, in this paper, an elastoplastic coupling analysis of high-strength concrete is conducted via conventional triaxial compression testing and cyclic loading testing. The failure process and the associated micro-cracking behaviour of the concrete during loading are monitored via the acoustic emission (AE) technique. By defining a confining stress function and plastic internal variables, the variations in the deformation parameters and the strength parameters with the plastic internal variables are analysed. With the increase in the plastic internal variables, the cohesion decreases, and the internal friction angle gradually increases. Based on the Mohr-Coulomb yield criterion, an improved cohesion weakening - friction strengthening (CWFS) model is proposed. The dilation angle of the concrete is smaller than the internal friction angle, and the non-associated flow rule should be adopted in the elastoplastic coupling model of the high-strength concrete. Finally, an elastoplastic coupling model is established based on the test results to provide an experimental and theoretical basis for numerical calculations and engineering applications. (C) 2020 Elsevier Ltd. All rights reserved.