Mechanical Characteristics and Mesostructural Damage of Saturated Limestone under Different Load and Unload Paths

Table 6

Pore-radius distribution proportion at different loading rates and initial peak stresses before and after the test.

	Pore radius	Minipore (%)	Mesopore (%)	Macropore (%)	Pore radius	Minipore (%)	Mesopore (%)	Macropore (%)
	Pretest or posttest	Pre	Post	Pre	Post	Pre	Post	Pretest or posttest
IA	As the loading rate increases	= 0.15	0.78	1.88	22.27	51.86	76.95	46.26
		mm/min	∆ = 1.1		∆ = 29.59		∆ = −30.69
		= 0.2	5.91	0.09	69.38	2.05	24.71	97.85
		mm/min	∆ = −5.82		∆ = −67.33		∆ = 73.14
		= 0.3	3.81	0.09	77.93	5.14	18.26	94.77
		mm/min	∆ = −3.72		∆ = −72.79		∆ = 70.06
	As the initial peak stress σ0 increases	σ0 = 2.5	5.91	0.09	69.38	2.05	24.71	97.85
		MPa	∆ = −5.82		∆ = −67.33		∆ = 73.14
		σ0 = 7.5	1.11	0.20	77.48	4.46	21.42	95.34
		MPa	∆ = −0.91		∆ = −73.02		∆ = 73.92
		σ0 = 12.5	4.50	0.40	44.63	8.48	50.87	91.12
RIA	As the loading rate increases	= 0.15	10.31	0.75	75.38	16.64	14.31	82.61
		mm/min	∆ = −9.56		∆ = −58.74		∆ = 68.30
		= 0.2	0.72	0.02	83.03	1.78	16.25	98.21
		mm/min	∆ = −0.70		∆ = −81.25		∆ = 81.96
		= 0.3	7.30	0.05	92.70	5.93	0	94.02
		mm/min	∆ = −7.25		∆ = −86.77		∆ = 94.02
	As the initial peak stress σ0 increases	σ0 = 2.5	0.72	0.02	83.03	1.78	16.25	98.21
		MPa	∆ = −0.70		∆ = −81.25		∆ = 81.96
		σ0 = 7.5	1.48	0.03	77.66	3.79	20.86	96.17
		MPa	∆ = −1.45		∆ = −73.87		∆ = 75.31
		σ0 = 12.5	1.48	0.04	78.43	3.38	20.09	96.57
DIA	As the loading rate increases	= 0.15	2.00	0.04	63.60	2.05	34.39	97.90
		mm/min	∆ = −1.96		∆ = −61.55		∆ = 63.51
		= 0.2	0.95	0.13	84.35	22.61	14.69	77.26
		mm/min	∆ = −0.82		∆ = −61.74		∆ = 62.57
		= 0.3	0.72	0.30	73.78	50.25	25.50	49.44
		mm/min	∆ = −0.42		∆ = −23.53		∆ = 23.94
	As the initial peak stress σ0 increases	σ0 = 2.5	0.95	0.13	84.35	22.61	14.69	77.26
		MPa	∆ = −0.82		∆ = −61.74		∆ = 62.57
		σ0 = 7.5	0.97	0.25	68.65	22.51	30.37	77.25
		MPa	∆ = −0.72		∆ = −46.14		∆ = 46.88
		σ0 = 12.5	4.19	0.46	62.12	14.08	33.69	85.46
		MPa	∆ = −3.73		∆ = −48.04		∆ = 51.77