Abstract:

How to consider the relevance of mechanical parameters of heterogeneous coal is a key issue to simulate coal bed. The 102 sets of experimental data including elastic modulus, uniaxial compressive strength and tension strength are derived from Wulong Mine of Fuxin city. Five dimensionless physical parameters including index of elastic modulus, index of uniaixal compressive strength, index of tension strength, index ratio of tension vs. elastic modulus (IRTE) and index ratio uniaixal of compressive strength vs. elastic modulus (IRUCE) are defined. Statistical analysis of the data shows that (1) Elastic modulus, uniaxial compressive strength and tension strength all follow statistical distribution, and may be fitted by Weibull distribution. (2) Indices of elastic modulus, uniaxial compressive strength and tension strength are correlative. (3) IRTE and IRUCE follow Weibull distribution. Then the probability model of heterogeneous coal with the correlation of the mechanical parameters is presented. The corresponding virtual generating system is developed. Two numerical cases are studied. In case 1 the virtual coal samples and the mechanical parameters are generated with the correlation and without the correlation of mechanical parameters, respectively; and the verifications are performed. The results show that the data from the former method are nearer to the experimental data. In case 2, the macroscopical stress-strain curve and the failure process of the numerical coal sample from the both methods under the conditions of plane strain and unaxial compression are studied. The simulating results from the former method are much better. Therefore the model proposed is a better way to simulate the mechanical heterogeneity of coal.

Key words: correlation of mechanical parameters, heterogeneous coal, probability model