Macro-Micro Response Characteristics of Surrounding Rock and Overlying Strata towards the Transition from Open-Pit to Underground Mining

Table 2

The final PFC mesoparameters of the rock samples.

Rock type	Parallel bond modulus (gPa)	Cohesion (kPa)	Tension (kPa)	Friction (°)	Stiffness ratio	Density (kg/cm^3)
Quaternary clay	0.17	7.37	7.37	18.2	2.1	1458
Dark gray cryptocrystalline dolomite	0.19	8.42	8.42	30.20	2.1	2089
Off-white coarse-grained dolomite	0.21	7.04	7.04	29.66	2.1	2090
Muddy quartz sandstone	0.16	7.04	7.04	29.52	2.1	2122
Phosphate strata	0.23	10.14	10.14	30.53	2.1	2155
Layered muddy dolomite	0.24	13.44	13.44	30.17	2.1	2122
Muddy dolomite	0.25	11.32	11.32	33.23	2.1	2065
Boundary phosphate strata	0.26	11.81	11.81	30.89	2.1	2078
Off-white layered dolomite	0.29	21.86	21.86	47.23	2.1	2025
Dark gray layered dolomite	0.26	22.67	22.67	30.17	2.1	2125

Note: the minimum particle radius is , and the particle size ratio is 1.5.