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

Table 5

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

Specimen number	Soaking time t (minutes)	Peak load Pcr (N)	Mode II fracture toughness KIIc (MPa m^0.5)		Degradation degree (%)
			Test value	Average value
AII0-1	0	1976.9 ± 0.01	0.286
AII0-2	0	2122.5 ± 0.01	0.271	0.272	0
AII0-3	0	2122.9 ± 0.01	0.259
AII50-1	50	2554.5 ± 0.01	0.278
AII50-2	50	2401.6 ± 0.01	0.265	0.265	−2.57
AII50-3	50	2301.3 ± 0.01	0.252
AII100-1	100	2388.8 ± 0.01	0.261
AII100-2	100	2443.7 ± 0.01	0.267	0.252	−7.35
AII100-3	100	2086.8 ± 0.01	0.228
AII200-1	200	2198.8 ± 0.01	0.234
AII200-2	200	2071.7 ± 0.01	0.245	0.229	−15.81
AII200-3	200	1730.5 ± 0.01	0.208
AII300-1	300	1986.1 ± 0.01	0.217
AII300-2	300	2095.9 ± 0.01	0.229	0.215	−20.96
AII300-3	300	1821.3 ± 0.01	0.199