An Experimental Study of the Uniaxial Failure Behaviour of Rock-Coal Composite Samples with Pre-existing Cracks in the Coal

Table 1

Mechanical properties of standard pure coal and rock samples [21].

Group	Uniaxial compression strength (UCS)	Elastic modulus	Poisson’s ratio
Standard pure coal sample	109.3 MPa	6.64	0.194
Standard sandstone sample	39.4 MPa	2.67	0.232