Using DEM to Analyze Crack Extension and Mechanical Behavior of Artificial Rock
Date Issued
2011
Date
2011
Author(s)
Chen, Yao-Rong
Abstract
Since World War II, the development of fracture mechanics is becoming complete. In the rock engineering field, fracture plays an important role on rock strength, so crack propagation is a big issue for studying fracture behavior of material. When the rock material damage is caused not by material strength but stress concentration of the pre-exist cracks, it becomes different from intact rock on failure strength and failure behavior, so rock mechanics can not help us do the analysis, design on engineering.
On the side of geology, due to the strong orogeny, the rock mass in Taiwan is plenty of discontinuities. The discontinuities, which are perceived as the pre-existing cracks in rock mass, can affect the strength of the rock mass. In view of this, it is benefit to know the pattern of fracture propagation behaviors of artificial rocks with pre-existing cracks under biaxial loading for earthquake disaster prevention.
This study was based on numerical analysis of data collected from laboratory test. The numerical simulation is executed by the distinct element method (DEM) based software, Particle Flow Code 2D.
In order to acquire the parameters for PFC2D simulating and verification the PFC2D results, this study refers to data of artificial rocks are made to apply the uni-axial compression test, the Brazilian disk test and the Central through Cracked Brazilian Disc test(Huang, 2010).
According to the simulation results, the lateral stress caused a great influence on fracture propagation behaviors. Behavior of specimen with single pre-exist crack is different between high and low confining pressure. The fracture propagation behavior was not obvious under higher lateral stress level. The broken area was concentrated near the pre-exist cracks and formed broad fracture lines.
Subjects
fracture coalescence
distinct element method
biaxial loading
numerical simulation
fracture mechanics
Type
thesis
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