A Coupled Elastoplastic Damage Model For Coal

It is so important to study the mechanical behaviour of the the coal as it hasbecome very important energy source. Deformation is the prerequisite conditionsandprecursors of country rock failure in the destruction of country rock of chamber.Therefore, we should create a model that includes the yield criterion for the coal. Theachievement of the research can be used in the prediction of the country rock damageand the optimization of support programs of the underground engineering such as coalmine engineering, and it will make a lot of economic and social benefits. According tothe characteristics of coal and rock, from the perspective of plastic potential, we dividethe force characteristics into elastic damgae and plstic damage by introducing thedamage consistency condition and plastic consistency condition. We can get the modelof the coal based on the force stage of the material. After the experiments in thelaboratory, we can obtain the parameters we need, and then substitute them into theformulas to get the theoretical results. Finally we find that the conclusion of the paper isconscious, and it is significant for the analysis of mechanical characteristics of coal. Thework done is mainly composed of following four parts:(1) When we analyze the mechnical behaviour of coal, it shows the coal’selastoplastic properties accompanied the occurrence and expansion of micro-cracks, sowe do the research from the standpoint of elastoplastic damage. Firstly, we should learnthe relevant theories.(2) It is necessary to do the triaxial compression tests with different confiningpressure by the Mechanics Test System, and the coal’s σ-εcurve can be obtained. Wecan get the values of the parameters of the theory model based on the test data, and thendo comparison between the theroy results and test results.(3) We can do the derivation of the formulas in the framework of the continuumdamage mechanics considering the coupled elastoplastic damage mechanical behaviourto get the theory model of the coal. According to the test results of the second step, thecoal’s σ-εcurve can be obtained by dealing with the model parameters.(4) In the end, we’ll examine the consistency of the theory and test by comparingthe theory σ-εcurves to the results of test to reach the conclusion.