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Table 5 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 diameter/mm Second stage Third stage Percentage of stress decrease (%)
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 50.0
18 0.50–1.47 0.019 9.6 1.47–1.95 0.018 15.8 18.2
30 0.50–2.13 0.048 4.8 2.13–2.80 0.043 10.7 10.4
Bolt diameter/mm Second stage Third stage Percentage of stress decrease (%)
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 54.4
18 0.50–1.71 0.461 6.7 1.71–1.95 0.353 14.6 23.4
30 0.50–2.35 0.622 3.9 2.35–2.80 0.587 10.6 5.6
Bolt diameter/mm Second stage Third stage Percentage of stress decrease (%)
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 80.0
18 0.50–1.71 0.111 9.6 1.71–1.95 0.090 15.8 18.9
30 0.50–2.13 0.148 4.8 2.13–2.80 0.128 10.7 13.5
Bolt diameter/mm Second stage Third stage Percentage of stress decrease (%)
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 33.3
18 0.50–1.71 0.024 6.7 1.71–1.95 0.022 14.6 8.3
30 0.50–2.13 0.058 3.9 2.13–2.80 0.056 10.6 3.4