Numerical Simulation Study on Influence of a Structural Parameter of D Bolt, an Energy-Absorbing Rock Bolt, on its Stress Distribution

Table 1

Input parameters for ground and D bolt.

Input parameters	Parameters	Values
For ground	Density (kg/m^3)	2390
	Elastic modulus (GPa)	11.1
	Poissons’ ratio	0.29
	Bulk modulus (GPa)	8.8
	Shear modulus (GPa)	4.3
	Cohesion c (MPa)	3.84
	Friction angle φ (°)	14.4
	Tensile strength (MPa)	8.0
For D bolt	Length (m)	2.4
	Density (kg/m^3)	7850
	Elastic modulus (MPa)	2.0 × 10^5
	Tensile yield strength (MPa)	240
	Cross-sectional area(m^2)	2 × 10^−4
	Number of D bolts in a roadway cross section	5
	Number of anchors for each D bolt	4
	Length of each anchor (m)	0.1
	Grout cohesive strength per unit length for each anchor (kN/m)	425
	Grout stiffness per unit length for each anchor (kN/m)	2 × 10^6
	Grout friction angle (°)	35