Abstract: To reveal the deformation characteristics and energy evolution characteristics of deep buried marble under high stress conditions and different stress paths, we examined the confining pressure effect and stress path influence of deformation and energy evolution during the deformation and failure of marble via conventional triaxial test and unloading triaxial test. Results reveal significant confining pressure effects under both loading and unloading stress paths. The damage expansion stress threshold and peak strength of marble under unloading conditions are lower than those under loading conditions. In terms of energy evolution, the proportion of energy dissipation stage in the process of deformation and failure under loading stress path accounts for a larger proportion than that under unloading stress path, while energy accumulation stage is greater in unloading stress path. The total energy and elastic strain energy corresponding to the damage expansion point under both stress paths are in good linear relations with confining pressure. At peak stress, the total energy, elastic strain energy and dissipation energy are linear functions of the confining pressure under loading stress path, and exponential functions under unloading stress path. Based on the above conclusions, a quantitative method to determine the failure point of marble is proposed. In association with the stress-strain relationship curve, the method effectively addresses the difficulty in determining the failure point of marble under high confining pressure. The research findings offer basis for the stability analysis of the surrounding rock of deep-buried chamber.

Key words: marble, stress path, deformation characteristics, energy evolution characteristics, failure point