Experimental Investigation into the Influences of Weathering on the Mechanical Properties of Sedimentary Rocks

Table 2

The variation in the ultimate tensile strength with weathering time.

Weathering time (days)	Test case	Uniaxial tensile strength (MPa)	Mean value (MPa)	Standard deviation (MPa)	Relative standard deviation (%)
0	Case 1-1	9.75	9.82	0.51	5.23
	Case 1-2	9.12
	Case 1-3	10.59
7	Case 2-1	6.53	6.91	0.38	5.50
	Case 2-2	6.72
	Case 2-3	7.48
14	Case 3-1	4.72	5.09	0.45	8.84
	Case 3-2	4.81
	Case 3-3	5.74
21	Case 4-1	3.75	4.02	0.21	5.15
	Case 4-2	3.98
	Case 4-3	4.33
28	Case 5-1	2.68	2.98	0.21	6.94
	Case 5-2	2.97
	Case 5-3	3.29