An elastic-plastic-soften constitutive model of coal considering its nonlinear elastic mechanical behavior

During the excavation of coal roadway,the surrounding rock often shows abnormal and large elastic deforma- tion. This behavior is difficult to explain with Hooke’s law. This indicates that even in the elastic deformation stage, the coal also show a strong nonlinear behavior. Compared with other rocks,since the distribution of various defects, such as pore,fracture,bedding and cleats,coal has more obvious heterogeneity. Firstly,the nonlinear elastic character- istics of coal are analyzed in this paper. Then it gives the constitutive equation of the nonlinear elastic mechanical be- havior and the numerical programming. NLEPS constitutive model is proposed considering the nonlinear elastic me- chanical behavior of coal. Finally,the effective numerical verification is carried out,and the application feasibility anal- ysis is carried out in coal roadway excavation. The calculation results indicate that the nonlinear deformation behavior of surrounding rock which is induced by coal roadway excavation is more accurately reflected by the calculation results based on NLEPS constitutive model. The nonlinear elastic constitutive model parameter has a clear physical meaning and can be widely used in coal mining engineering.