Continuum-discontinuum cellular automaton method for rock fracturing process modelling
In recent years,a continuum-discontinuum numerical analysis method is developed to simulate the fracturing process of rocks by our research team.This method is an integration of multiple techniques and theories,such as rock mechanics,fracture mechanics,elasto-plastic mechanics,level set method,cellular automaton,partition of unity and computational mathematics,etc.The associated numerical code has been compiled in C++ environment.The characteristics and functions of the method are summarized as: 1)the fracture and fracture propagation is traced and positioned by level set method,which is independent of calculation grids.By doing so,no explicit meshing for crack surface and no remeshing for crack growth are needed; 2)the cellular automaton updating rule is developed locally and avoids the complexity in the solution of large scale linear equations herein; 3)the crack can initiate from any place in rock mass and propagate along any direction based on the local stress state.4)the excavation modeling of arbitrary shape and multiple excavation steps of underground caverns can be implemented conveniently; 5)rock fracturing process from crack initiation,propagation,multiple cracks junction,interaction and coalescence,crack open,close and slip,to rock blocks formation and block movement can be well simulated; 6)microseisms and energy evolution can be recorded and some stability evaluation indexes,such as failure approach index(FAI),local energy release rate(LERR)index,are incorporated.The new theories and techniques used in the method are: 1)Based on Griffith fracture theory and Mohr-Coulomb criterion,a mixed fracture criterion for multiple cracks growth and microcrack initiation for rock material is proposed.2)A discontinuous cellular automaton updating rule suitable for frictional contact of rock is proposed simultaneously with the Newton’s iteration method for nonlinear iteration.3)A method to treat the junction and coalescence of multiple cracks,and junction criterion and coalescence criterion for brittle material are proposed for rock material.4)in order to overcome the tracking error in the level set approximation for crack junction and coalescence,a dichotomy searching algorithm is proposed.5)A theory for fracturing to blocks of rock mass are developed based on mathematical collection theories.The self-developed continuum-discontinuum numerical analysis method has been successfully applied to simulate the fracturing processes,including crack initiation,propagation,coalescence,block formation and movement,of rock mass in deep underground excavations.
Xia-Ting Feng Fei Yan Peng-Zhi Pan
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics,Chinese Academy of Sciences
国际会议
The 12th International Conference on Analysis of Discontinuous Deformation(第12届非连续变形分析国际大会)
武汉
英文
13-13
2015-10-16（万方平台首次上网日期，不代表论文的发表时间）