Modified Fracture Mechanics Approach for Hydraulic Fracturing Stress Measurements

Table 1

Physical and mechanical properties of the rock samples.

Lithology	Density; (g/cm^3)	Elastic modulus; (GPa)	Poisson’s ratio	Tensile strength; (MPa)	Fracture toughness; (MPa m^1/2)
Granite	2.65	50.0	0.18	10.87	1.07
Red sandstone	2.50	28.8	0.18	5.3	0.78