Research on Arch Model and Numerical Simulation of Critical Water and Sand Inrush in Coal Mine near Unconsolidated Layers

Table 4

Simulation results of ratio of crack width to particle diameter when the transition archs buckling under different conditions.

Hydraulic pressure (MPa)	2.0	2.0	2.0	2.0	2.0	0.001	0.001	0.001
Particle’s bonding strength (N)	1.5^6	1^6	5^5	1^5	1^3	1	1^3	1^4
Critical ration of crack and sand	15.0	8.6	5.9	5.0	4.9	4.9	5.2	5.4