Fracture Characteristics Analysis Of Layered Rock Plates Under Loading Condition

Under the concentrated loading and the uniform loading, the tests on the brittlefracture, hinged arching until the rock-arch instability of the sandstone plate wereconducted using loading device, and the sensitivity of influent factors on the rock-archfailure were analyzed by numerical test based on the particle flow code (PFC). The resultsshowed that sandstone plate instability presented four phases: small deformation elasticstage, 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 instabilitywas much higher than that under the concentrated loading condition, and the maximumlateral force was almost the same. The number of acoustic emission (AE) and itspositioning results of the sandstone plate showed that the extent of the plate damage underthe uniform loading was higher than that under the concentrated loading condition. Thefriction coefficient effect, size effect, loading rate effect and the initial horizontal forceeffect on the rock-arch instability were analyzed by the PFC3Dnumerical experiment.Under the concentrated loading, the numerical computation of double-deck rockplates instability with the boundary of two fixed sides and two free sides was analyzed bythe PFC3Dprocedure. The results showed that there existed a best particle size when thevertical force of rock plate damage reached a maximum value as the rock plate particleradius changes from small to large; The rock damage peak force curve generally presentedan upward trend with the increase of rock plate temperature; When the thickness ofdouble-deck rock plates was constant, the rock damage peak force increased with theincrease of rock plate thickness; When rock plate boundary conditions changed fromhinged support to restrained support, the horizontal force of rock plate damage decreasedobservably.