Pressure-Shear Crack Initiation and Expansion Mechanism of Complex Cracked Rock Mass under the Seepage Stress

Table 1

The physical parameters of the rock mass.

	Sandstone	Coal seam	Cement rock	Water-bearing sandstone	Cement rock
Thickness m	20	3	30	40	65
Elastic modulus (GPa)	2.6	16	18	36	18
Compressive strength (MPa)	60	25	40	90	35
Poisson’s ratio	0.2	0.32	0.25	0.15	0.27
Permeability coefficient (m/d)	0.01	0.01	0.01	100	0.01
Homogeneity	5	10	2	4	2