Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical properties
vary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory and
displacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittent
cracks, 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 butt
cleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of butt
cleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination of
face cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus of
coal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent on
the elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When the
distance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initially
increased and then decreased with increasing of the face cleat inclination.
