Permeability estimate of underground long-wall goaf from P-wave velocity and attenuation by lab-scale experiment on crushed rock samples

摘要: Abstract In this study, forty-five crushed rock samples were formed from and coal particles of different sizes to simulate the fragmented condition a goaf area in an underground mine. The porosity (φ) range was based on field observations actual goafs. permeability (k) measured by reducing size fragments lab-scale particles. Ultrasonic wave velocity (VPG) attenuation (β) for porosities, particle frequencies. ratio seismic wavelength adjusted match that parameters goaf. results showed conformed Kozney-Carman (K C) equation with percolation threshold 0.06. dependent φ4. variations (η) (ξ) defined intact rock. η linear relationship square root tortuosity (τ) τ = 5–10. ξ approximately part K C equation. An empirical is proposed equation, involving velocity, size. estimated modified good agreement data. as 1.0 × 104–6.5 × 105 d properties