Comparative Analyses Concerning Triaxial Compressive Yield Criteria of Coal with the Presence of Pore Water

Table 4

Triaxial strength fitting results of five effective yield criteria for saturated coal based on the least absolute deviation.

Category		Coulomb criterion			Parabolic Mohr criterion			Hoek-Brown criterion
		(MPa)	(°)	(MPa)	(MPa)	(MPa)	(MPa)		(MPa)	(MPa)
DT water-saturated	0.01	3.403	34.99	5.47	21.53	0.0005366	5.59	16.89	12.18	3.44
	0.05	3.522	39.58	6.68	23.83		6.33	23.23	12.18	4.63
	0.08	4.458	42.97	8.23	27.13		8.07	33.1	12.18	6.97
Category		Quadratic polynomial criteria					Exponential yield criterion
			(MPa)	(MPa)	(MPa)			(MPa)	(MPa)	(MPa)
DT water-saturated	0.01	10.5	13.31		2.94	0.01	8.758	12.18	73.85	3.99
	0.05	8.424	18.34	0.0001455	4.66	0.05	16.17	12.18	71.28	5.08
	0.08	21.03	12.18		5.73	0.08	59.29	12.18	55.24	6.91