Papers by Keyword: RFPA2D

Abstract: In order to study the damage and sptial spatial and temporal distribution of acoustic emission of rocks under uniaxial cyclic load-unload, test of rocks with various kinds of heterogeneity under uniaxial cyclic load-unload disturbance was conducted using numerical simulation software RFPA2D.Figure destruction and acoustic emission - load curve of rocks were obtained from the test.The results show that destroy of the rock was produced from tensile stress concentration area surrounding the hole. as the load increases,crack developmented to the edge of the rock.when homogeneity of rock was low, crack development with irregularity due to defects of rocks. with the increasing homogeneity of rock, damage evolution mode under uniaxial cyclic load-unload disturbance transition from ductile to brittle.damage evolvement process can be responsed by acoustic emission. with the increasing homogeneity of rock. The maximum number of acoustic emission Continuously improve and exhibit unexpected. Kaiser effect of acoustic emission under cyclic loading is significantly This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. .

Abstract: It is very important to study the structure effect of cavity group for controlling disasters in engineering and coordinating mining of the hidden danger resources. The cavity group structure was defined and classified. The structure effect of the twelve kinds of working conditions were simulated by using Rock Failure Process Analysis code (RFPA^2D). the results show as follows: 1) The stability order of the typical cavity group structures was the second one, the third one and the first one; 2) The phenomena of small cavities interpenetrating and forming a big cavity often appeared in the kinds of the first and the third structure in the process of system catastrophe, but not in second structure; 3) The system appeared catastrophe easily with the number rising of the first structure, the third structure taking the second place and the second structure taking the last place; 4)The risk of the system consisting of two groups of the third structures was greater than one of the system consisting of one group of the first structure; 5) he more the number of the poor stability structures was in the up of system, the more poor stability the system had; 6) The same structures were placed in the upper and lower order in system, the lower structure would appear prior into the failure and instability status.

Abstract: By using numerical code RFPA2D (Rock Failure Process Analysis), the evolution of fracture around cavities subjected to uniaxial and polyaxial compression is examined through a series of model simulation. It is shown from the numerical results that the chain of events leading to the collapse of the cavity may involve all or some of the fractures designated as primary tensile, shear and remote fracture. Numerical simulated results reproduce the evolution of three types of fractures. Under the condition of no confining pressure, the tensile mode dominates with collapse coinciding with the sudden and explosive appearance of the secondary tensile fracture; at moderate higher confining pressure, the tensile mode is depressed, comparatively, the shear effect is strengthened. Nevertheless, tensile fractures especially in remote fractures stage still play a role; at higher pressure, the shear fracture dominates the remote fractures. In addition, the evolution and interact of fractures between multiple cavities is investigated, considering the stress redistribution and transference in compressive and tensile stress field.