Numerical Simulation On Crack Evolution Based On General Particle Dynamics

In the fields of deep mining engineering and rock exploitation,there are lots of uncertainties on the mechanical properties and failure modes of rock materials,due to the inherent variability of rock and defects,cracks,voids in the rock mass.The study on the mechanical properties and failure modes of rock materials has been getting more and more attentions from researchers all around the world.In this paper one kind of numerical simulation method is used to analyze the mechanical properties and failure modes of two-dimensional and three-dimensional models.Former researchers chose the methods,such as finite difference method,finite element method,numerical manifold method.But these methods could not be applied to the problem of large deformation.Meshless particle method can solve this problem easily.As the name suggests,meshless particle method does not need to generate the grid,and uses discrete particles to bear the loads.In this paper,the numerical simulation of two-dimensional and three-dimensional models was done by GPD program.The main contents of this paper are as follows:(1)Write and optimize the pre-processing program of GPD program.By importing the Auto CAD file to the program created by C language,we can translate it to a data file which is friendly to the GPD program.This makes it very convenient to build a model.(2)By using kernel function approximation and particle approximation method,and introducing the constitutive equation of rock strength,the GPD program is written to simulate the cracks initiation,growth and coalescence of rock models with pre-exist cracks.The software system is also developed for the post-processing and data visualization.(3)By comparing the numerical results of the two-dimensional crack propagation of the rock models with two cross-flaws,which have three different crack spacings and two different crack inclinations,we find that wing cracks have a majority in the crack initiation and propagation,and shear cracks are rare under uniaxial compressive loads.As the crack spacing increases from 0mm to 20 mm,the initiation stress and peak stress have dropped.Also the initiation stress and peak stress are higher than when the crack inclination is 45 degrees than the crack inclination is 0 degree.(4)By comparing the numerical results of the three-dimensional crack propagation of the rock models with two cross-flaws,which have three different crack spacings and the same crack inclinations,we find that wing cracks still have a majority in the crack initiation and propagation.The initiation stress and peak stress both increase with the crack spacing.