Strength and Failure Characteristics of Natural and Water-Saturated Coal Specimens under Static and Dynamic Loads

Table 4

Natural and saturated specimen parameters under triaxial static-dynamic compressive tests.

Specimen; number	Saturated; status	Diameter/mm	Length/; mm	Density; gcm^−3		Confining pressure/; MPa	Axial pressure; /MPa	Strain rate; /s^−1	Strength/MPa		Failure strain/%
				Dry	Wet				Tested	Average	Tested	Average
D1	Natural	4.97	3.04	1.42	/		8	76	54.23	66.63	1.07	0.922
D2	Natural	4.98	2.96	1.42	/		12	59	65.07		0.91
D3	Natural	4.97	2.93	1.43	/	4 MPa	16	59	68.27		0.98
D4	Natural	4.98	2.99	1.44	/		20	60	75.39		0.98
D5	Natural	4.97	3.13	1.41	/		36	63	70.16		0.67
D6	7D water	4.97	3.06	1.44	1.51		8	68	63.21	74.55	1.22	1.134
D7	7D water	4.98	3.07	1.44	1.52		12	68	70.29		1.17
D8	7D water	4.98	3.06	1.41	1.49	4 MPa	16	81	80.86		1.12
D9	7D water	4.98	3.07	1.40	1.48		28	70	82.71		1.02
D10	7D water	4.97	3.02	1.44	1.49		36	67	75.67		1.14