The Model for Calculating Elastic Modulus and Poisson's Ratio of Coal Body

摘要

Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical propertiesvary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory anddisplacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittentcracks, the model was established to calculate the elastic modulus and Poisson's ratio of coal body combined with cleat.By analyzing the model, it also obtained the influence of the parameter variation of coal rock block, face cleat and buttcleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of buttcleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination offace cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus ofcoal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent onthe elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When thedistance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initiallyincreased and then decreased with increasing of the face cleat inclination.