Experimental Study on the Brittle-Ductile Response of a Heterogeneous Soft Coal Rock Mass under Multifactor Coupling

Table 2

Brittle-ductile modulus for different rocks.

(a)

Tennessee marble (data from [55, 57])
Confining pressure (MPa)	0.00	3.45	6.90	13.80	20.70	34.50
Peak strength (MPa)	130	145	160	180	195	245
Residual strength (MPa)	10	60	80	110	130	230
Brittleness modulus (MPa)	174545	104615	85333	74666	34666	5333
	1.000	0.599	0.489	0.428	0.199	0.031

(b)

Gebdykes dolomite (data from [58])
Confining pressure (MPa)	0	5	20	40	90
Peak strength (MPa)	60	98	131	150	180
Residual strength (MPa)	10	42	101	148	200
Brittleness modulus (MPa)	16667	8000	3529	2000	1900
	1.000	0.480	0.212	0.120	0.113

(c)

Vosges sandstone (data from [59])
Confining pressure (MPa)	0	10	20	40	60
Peak strength (MPa)	31	74	92	108	110
Residual strength (MPa)	22	38	75	94	107
Brittleness modulus (MPa)	6923	4500	4232	3337	1060
	1.000	0.650	0.561	0.482	0.153

(d)

Heterogeneous soft coal rock mass
Confining pressure (MPa)	0	1	2	4
Peak strength or critical inflection point value (MPa)	4.5	6.2	7.1	8.2
Residual strength or ductility strength (MPa)	2.2	8.3	10.1	15.3
Brittleness modulus (MPa)	575	241	143	70
	1.000	0.330	0.248	0.121