Further development of the distinct lattice spring model for quasi-brittle crack propagation in concrete and its application in underground engineering

Abstract

This paper further extends the ability of the distinct lattice spring model (DLSM) to predict quasi-brittle crack propagation in concrete. In contrast to brittle crack propagation, most experimental results confirm that the crack propagation in concrete is quasi-brittle. The DLSM was originally developed to study the brittle fracturing of rock. Whether and how it could be applied to quasi-brittle crack propagation has not been systematically studied. In this work, considering aspects of the geometric non-uniformity, material heterogeneity and micro-mechanical constitutive model, the ability of the DLSM to solve quasi-brittle crack propagation has been systematically investigated. The main contributions of this work are that it (1) confirmed the necessary for the DLSM to have a new micro-mechanical constitutive model to solve the quasi-brittle crack propagation problem; (2) established a new micro-mechanical constitutive model for quasi-brittle crack propagation; and (3) proposed a formula for the relationship between the micromechanical and macroscopic material parameters of the concrete. The new micromechanical constitutive model proposed in this paper has been systematically verified by three-point bending experimental results of various grades of concrete. Finally, the new constitutive model has been adopted to analyse the cracking of the concrete lining.