Experimental Study on the Effect of Gas Pressure on Ultrasonic Velocity and Anisotropy of Anthracite

Table 3

Test results of P- and S-wave ultrasonic velocities of the coal samples under different gas pressures.

(MPa)	(m/s)			(m/s)
	-0.1	1793	1733	1677	982	926	871
0.2	1733	1673	1650	959	911	863
0.4	1706	1653	1635	951	905	858
0.6	1691	1644	1627	947	901	851
0.8	1683	1635	1614	943	897	847
1.0	1675	1629	1607	937	893	845
1.2	1664	1621	1600	933	889	841
1.4	1652	1613	1596	927	886	841