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Table 3 The measured stress of the composite rock-bolt bearing structure and acceleration rate of surrounding rock displacement

From: Experimental studies on the effects of bolt parameters on the bearing characteristics of reinforced rock

Bolt length/mm Second stage Third stage
Kinetic pressure coefficient range Peak stress/MPa Vertical closure acceleration rate of displacement/mm/MPa Kinetic pressure coefficient range Residual stress/MPa Vertical closure acceleration rate of displacement/mm/MPa
(a) Vertical stress at Sensor 1
No bolts 0.50–1.00 0.008 14.4 1.00–1.23 0.004 25.2
1600 0.50–1.47 0.019 8.5 1.47–1.95 0.018 15.0
1800 0.50–1.95 0.049 7.2 1.95–2.42 0.029 14.9
2000 0.50–1.95 0.062 6.8 1.95–2.58 0.057 10.8
2400 0.50–2.35 0.072 6.8 2.35–2.70 0.065 10.2
Bolt length/mm Second stage Third stage
Kinetic pressure coefficient range Peak stress/MPa Rib convergence closure acceleration rate of displacement/mm/MPa Kinetic pressure coefficient range Residual stress/MPa Rib convergence closure acceleration rate of displacement/mm/MPa
(b) Vertical stress at Sensor 2
No bolts 0.50–1.00 0.114 12.0 1.00–1.23 0.052 15.2
1600 0.50–1.71 0.461 6.7 1.71–1.95 0.353 14.6
1800 0.50–1.71 0.505 4.4 1.71–2.42 0.452 12.7
2000 0.50–1.95 0.530 4.3 1.95–2.58 0.364 9.5
2400 0.50–1.95 0.536 4.3 1.95–2.70 0.365 6.8
Bolt length/mm Second stage Third stage
Kinetic pressure coefficient range Peak stress/MPa Vertical closure acceleration rate of displacement/mm/MPa Kinetic pressure coefficient range Residual stress/MPa Vertical closure acceleration rate of displacement/mm/MPa
(c) Horizontal stress at Sensor 1
No bolts 0.50–1.00 0.060 14.4 1.00–1.23 0.012 25.2
1600 0.50–1.71 0.111 9.6 1.71–1.95 0.090 15.8
1800 0.50–1.95 0.150 7.2 1.95–2.42 0.100 14.9
2000 0.50–2.35 0.150 7.0 2.35–2.58 0.126 12.2
2400 0.50–2.35 0.152 6.8 2.35–2.70 0.133 10.2
Bolt length/mm Second stage Third stage
Kinetic pressure coefficient range Peak stress/MPa Rib convergence closure acceleration rate of displacement/mm/MPa Kinetic pressure coefficient range Residual stress/MPa Rib convergence closure acceleration rate of displacement/mm/MPa
(d) Horizontal stress at Sensor 2
No bolts 0.50–1.00 0.009 12.0 1.00–1.23 0.006 15.2
1600 0.50–1.71 0.024 6.7 1.71–1.95 0.022 14.6
1800 0.50–1.95 0.080 5.6 1.95–2.42 0.058 13.2
2000 0.50–1.95 0.080 4.3 1.95–2.58 0.064 9.5
2400 0.50–2.35 0.086 4.3 2.35–2.70 0.075 8.9