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ABSTRACT: Assessment of rockburst potential in the rockmass is one of the main challenges in tunnel design. The phenomenon of rockburst is often linked with brittle failure characteristics of the rock leading to high strain-energy release and spalling, fractures, and damage around the tunnel boundary. This paper develops a synthetic sandstone as a model material for bursting rocks prepared in the laboratory to advance the study of the rockburst phenomenon. The synthetic sandstone is composed of fine-grained F-75 Ottawa sand, type I/II cement, and water. The brittle behavior of the material was studied based on the full stress-strain curve observed in the synthetic sandstone. Also, the synthetic rockburst-susceptible rock suitability is evaluated using several empirical criteria, such as strength brittleness index, burst energy coefficients, a brittleness index modified, and a strain energy storage index. The laboratory tests found that the material can be easily reproduced in different shapes and geometry with repeatable properties. The elemental testing damage characterization of the synthetic sandstone shows that the material is similar to bursting rock. The synthetic sandstone will be further expanded in laboratory-scale physical model testing using a true-triaxial cell to study the complex problem of rockburst. 1. INTRODUCTION The sudden, violent manner of rockburst is a complex phenomenon that remains a significant hazard for many deep underground excavations (Simser, 2019). Understanding the primary cause of rockburst and its interdependence enables engineers to make more informed risk management and mitigation decisions. One approach to improve the understanding of the failure process for the excavation is building a reproducible physical model under controlled circumstances in different shapes and geometry (Klammer et al., 2017). Although categorized as medium strength rocks, historical evidence has shown that rockburst can occur in this lithology (Q. M. Gong et al., 2012; Naji et al., 2019; Sun et al., 2016). Researchers have attempted to produce artificial rocks similar to natural sandstone in the past few decades. The efforts include a sintering process of natural sand grains with artificial beads, artificial cement, 3D printing, and chemical reaction utilization (David et al., 1998; Huang and Airey, 1998; Ishutov et al., 2015; Osinga et al., 2015; Rice-Birchall et al., 2021). However, these methods necessitated extensive resources and were considered limited in terms of ease of preparation. |
