Investigation of meso-mechanical properties of Jinping dolomitic marble based on flat-joint model

Brittle rock has the mechanical characteristics of a high ratio of uniaxial compressive strength to tensile strength, brittle-ductile transition, and so on. The mineral meso-structure of brittle rock shows the interlocking behavior and there are some microcracks between the mineral grains, so it is difficult to analyze the mechanical characteristics accurately with a regular constitutive model. The previous numerical models have some limitations when applied to brittle rock, that they cannot provide sufficient internal interlocking and are incapable of considering the microcracks. These limitations are addressed by using the updated flat-joint contact model to join notional polygonal particles with an initial gap and increasing the particle coordination number by adding flat-joint contacts to more particles that are within some non-zero distance of one another via the range coefficient contact identification method. A comparison of experimental and numerical results confirms that the updated flat-jointed model provides a good match with the mechanical properties of brittle rock. In this paper, we investigate the influence of mineral meso-structure (micro-cracks, range coefficient, and radius multiplier) on the meso-mechanical properties of Jinping dolomitic marble via the updated flat-joint contact model under direct-tension tests and compression tests. It is found that the updated model can reproduce the microstructure effect of brittle rock and can better simulate the mechanical characteristics of the brittle rock than conventional models, such as high strength ratio, brittle-ductile transition, initial nonlinearity, and different modulus in compression and tension.