Damage constitutive model of jointed rock mass considering structural features and load effect

Rock masses in underground engineering are usually damaged, which are caused by rock genesis and environmental stress. Studying the constitutive relationship between rock strength and deformation under loading is crucial for the design and evaluation of such scenarios. The new damage constitutive model considering the dynamic change of joint damage was developed to describe the behavior of rocks under loading in this work. First, considering the influence of jointed rock mass structural features in their entirety, the Drucker–Prager criterion and the Hoek–Brown criterion were combined. Second, based on the idea of macro–micro coupling, the calculation formulae of damage variables were derived. Finally, the damage constitutive model of the jointed rock mass was established, and the proposed model was fitted and compared with the test data. Results show that the variation rules for damage value and peak strength are opposite, and the stress–strain is highly sensitive to changes in the parameter s of the model. Moreover, the proposed model can accurately describe the effect of joint deterioration on the entire process of rock mass compression failure, which shows that the damage constitutive models are useful for evaluating the strength characteristics of jointed rock mass in engineering practice.