Abstract: This paper attempts to make mechanical and permeability characteristics of cement bound coals closer to those of undisturbed coals. It uses triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling of coal containing methane and selects cement as a binder. The triaxal compressive properties of cement bound coals with different binder ratios are compared with those of undisturbed coals. The characteristic values for the mechanical and permeability characteristics of the cement bound coals are evaluated quantitatively using Euclidean distance based similarity methods. The results show that: as binder ratios increase, the peak principal stress difference and the elastic modulus of the cement bound coal probably increase following a positive exponential function trend. Poisson's ratio decreases following a negative exponent function trend. As the binder ratio increases, the initial permeability and the minimum permeability of the cement bound coal have the decreasing trend of exponent function. The penetration rate of change is smaller and smaller. The permeability-axial strain curve is gentler. The mechanical and permeability characteristics of the cement bound coal with the cement binder ratio #IV are the closest to those of undisturbed coal. This type of cement bound coal can be used as the similar material for simulating the undisturbed coal.

Key words: binder, mechanical characteristics, permeability, similar material, coal