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

Table 5

Triaxial strength fitting results of five types of effective strength criteria for coal during a seepage process based on the least absolute.

Category		Coulomb criterion			Parabolic Mohr criterion			Hoek-Brown criterion
		(MPa)	(°)	(MPa)	(MPa)	(MPa)	(MPa)		(MPa)	(MPa)
DT seepage	0	12.14	29.36	2.27	27.42		1.69	5.085	40.16	2.09
		11.29	29.36	2.28	24.72	0.001393	2.68	5.649	36.14	2.09
BD seepage	0	6.546	40.08	1.24	27.85	5.867	1.87	8.983	27.97	1.54
		5.284	40.08	1.24	18.55		2.01	12.48	20.14	1.54
XH seepage	0	6.55	24.23	0.29	20.05	10.46	0.17	3.24	20.14	0.22
		5.875	24.23	0.29	16.79	7.194	1.58	3.72	17.55	0.22
Category		Quadratic polynomial criterion					Exponential yield criterion
			(MPa)	(MPa)	(MPa)			(MPa)	(MPa)	(MPa)
DT seepage	0	2.801	30.84	0.001214	1.65	0	14.28	20.68	60.05	0.17
		4.342	24.96		1.85		19.71		60.64	0.23
BD seepage	0		29		0.94	0	4.617	28.12		1.25
			22.93		1.13		1.715	28.03	26.28	0.0054
XH seepage	0	0.7782	19.68	2.075	0.00065	0	3.288	19.87	29.27	0.0026
		1.94	13.62		0.089		4.296	15.73	29.27	0.0012