Experimental Investigation of Water-Sand Mixed Fluid Initiation and Migration in Filling Fracture Network during Water Inrush

Table 3

Critical conditions of particle entrainment.

Range of particle size (mm)	Critical hydraulic gradient/Jc	Critical velocity/ (mm/s)
0.075–0.150	3.40–5.90	1.96–2.35
0.150–0.300	4.25–6.80	2.21–2.70
0.300–0.600	5.10–7.60	2.28–3.20