Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding

Table 2

Mode I fracture toughness of Type A mudstone specimens for different soaking times.

Specimen number	Soaking time t (minutes)	Peak load Pcr (N)	Mode I fracture toughness KIc (MPa·m^0.5)		Degradation degree (%)
			Test value	Average value
AI0-1	0	1839.5 ± 0.01	0.850
AI0-2	0	1781.1 ± 0.01	0.823	0.850	0
AI0-3	0	1897.9 ± 0.01	0.877
AI50-1	50	1694.5 ± 0.01	0.783
AI50-2	50	1649.1 ± 0.01	0.762	0.780	−8.24
AI50-3	50	1720.5 ± 0.01	0.795
AI100-1	100	1544.5 ± 0.01	0.714
AI100-2	100	1567.9 ± 0.01	0.724	0.690	−18.82
AI100-3	100	1367.3 ± 0.01	0.632
AI200-1	200	1304.8 ± 0.01	0.603
AI200-2	200	1250.7 ± 0.01	0.578	0.605	−28.82
AI200-3	200	1372.5 ± 0.01	0.634
AI300-1	300	1133.4 ± 0.01	0.524
AI300-2	300	1218.0 ± 0.01	0.563	0.535	−37.06
AI300-3	300	1122.1 ± 0.01	0.518