Rock-Arch Instability Characteristics of the Sandstone Plate under Different Loading Conditions

Abstract

Under the concentrated loading and the uniform loading, the tests on the brittle fracture and the hinged arching until the rock-arch instability of the sandstone plate were conducted using self-developed loading device, and the sensitivity of influent factors on the rock-arch failure was analyzed by numerical test based on the particle flow code (PFC). The results showed that sandstone plate instability presented four phases: small deformation elastic stage, brittle fracture arching stage, rock-arch bearing stage, and rock-arch instability stage. Under the uniform loading, the maximum vertical force of the rock-arch instability was much higher than that under the concentrated loading condition, but the maximum lateral force was almost the same. The number of acoustic emission (AE) and its positioning results of the sandstone plate showed that the extent of the plate damage under the uniform loading was higher than that under the concentrated loading condition. The friction coefficient effect, size effect, loading rate effect, and the initial horizontal force effect on the rock-arch instability were analyzed by the PFC3D numerical experiment.