Study on failure mechanism of room and pillar with different shapes and configurations under uniaxial compression using experimental test and numerical simulation

Experimental and discrete element methods were used to investigate the failure behavior of room and pillar with different configurations under uniaxial loading. Concrete samples with dimension of 15 cm x 15 cm x 5 cm were prepared. Within the specimens, rooms and pillars with different configurations were provided. The room dimension was 1 cm x 1 cm, and the pillar dimension was according to the room configuration. Twelve different configurations were chosen for rooms and pillars. The axial load was applied to the model by rate of 0.05 mm/min. The results show that the failure process was mostly governed by both the non-persistent joint angle and joint number. The compressive strength of the specimens was related to the fracture pattern and failure mechanism of the pillars. It was shown that the shear behaviour of pillars was related to the number of the induced tensile cracks, which increased by increasing the room angle. The compressive strength of samples increased with the increase of the room angle. The failure pattern and failure strength are similar in both methods, i.e., the experimental testing and the numerical simulation.