Evaluating Long-Term Strength and Time to Failure of Sandstone with Different Initial Damage

Table 4

LTS of rock with different initial damage obtained by four methods.

Initial damage state	LTS (MPa)
	Method 1	Method 2	Method 3	Method 4
D1	27.4∼29.2	27.4∼29.4	27.4∼29.4	28.8
D2	26.0∼28.0	23.5∼27.4	23.5∼27.4	27.2
D3	25.5∼27.4	23.5∼27.4	23.5∼27.4	26.0
D4	23.4∼24.6	23.5∼27.4	23.5∼27.4	24.4

Note. Methods 1, 2, 3, and 4 denote the isochronous stress-strain curve method, the steady creep discriminated method, the volumetric strain inflexion point determined method, and the intersection of steady creep rate method, respectively.