Research Article
The Ultrasonic P-Wave Velocity-Stress Relationship and Energy Evolution of Sandstone under Uniaxial Loading-Unloading Conditions
Table 2
Fitting results of the relationship between the P-wave velocity and stress of the sandstone specimens.
| | Specimens | Stage | k | | Relationship function | R2 |
| | US1 | L1 | 115.00 | 3805.5 | | 0.97 | | U1 | 109.17 | 3844.8 | | 0.98 | | L2 | 128.81 | 3762.1 | | 0.97 | | U2 | 106.85 | 3849.2 | | 0.99 | | L3 | 88.92 | 3881.7 | | 0.93 |
| | US2 | L1 | 182.67 | 4190.0 | | 0.91 | | U1 | 158.64 | 4338.3 | | 0.94 | | L2 | 166.67 | 4265.0 | | 0.93 | | U2 | 168.85 | 4278.8 | | 0.98 | | L3 | 169.22 | 4288.1 | | 0.98 |
| | US3 | L1 | 424.60 | 2217.4 | | 0.98 | | U1 | 356.03 | 2534.4 | | 0.99 | | L2 | 446.74 | 2146.3 | | 0.96 | | U2 | 380.12 | 2449.0 | | 0.99 | | L3 | 391.17 | 2322.5 | | 0.96 |
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