Roadway Support in Deep “Three-Soft” Coal Seam: A Case Study in Yili Mining Area, China

Table 3

Parameters of the structural elements.

Property	Emod (GPa)	Ytension (kN)	Xcarea (m^2)	Gr_fric (°)	Gr_per (m)	Gr_coh (kN/m)	Gr_k (GPa)	Density (kg/m^3)	P_ratio	Thickness (m)
Bolt	210	180	3.80 ∗ 10^−4	25	0.1	150	0.175	7850	—	—
Cable	195	353	3.80 ∗ 10^−4	25	0.1	150	0.175	7850	—	—
Shell	26	—	—	—	—	—	—	2400	0.25	0.15

Emod is Young’s modulus, Gr_coh is grout cohesive strength (force) per unit length, Gr_fric is grout friction angle (degrees), Gr_k is grout stiffness per unit length, Gr_per is grout exposed perimeter, Xcarea is cross-sectional area, and Ytension is tensile yield strength (force).