Fig 1.
Flow chart of comprehensive evaluation method.
Fig 2.
Hydraulic radius determination method diagram.
Fig 3.
Mathews stability chart.
Fig 4.
Limit span method (under the condition of no support or local support).
Fig 5.
Determination of limit span of the stope.
Fig 6.
Self-stabilization time judgment based on RMR classification.
Table 1.
Jv and Kv comparison table.
Table 2.
ESR value.
Fig 7.
Q system rock classification and support chart.
In this figure: ①No support required; ②Point anchor support;③System bolt support; ④System bolt support (plain shotcrete, thickness of 4~5cm); ⑤System bolt and steel fiber shotcrete, thickness 5~9cm; ⑥System bolt and steel fiber shotcrete, thickness of 9~12cm; ⑦System bolt and steel fiber shotcrete, thickness of 12~15cm; ⑧System bolt and steel fiber shotcrete, thickness > 15cm, plus shotcrete reinforced ribs; ⑨Mold concrete lining.
Fig 8.
The algorithm flow chart of stope stability comprehensive evaluation system.
Fig 9.
Location of Jiaojia Gold Mine.
Fig 10.
Experimental evaluation of stope design.
Fig 11.
Drawing of rock mass structural plane of measuring point in the -570m level by Sirovision.
Fig 12.
Schmitt diagram and rose diagram of joint in the -570m level (a) Schmitt diagram; (b) rose diagram.
Table 3.
Structural plane information in the -570m level.
Fig 13.
ZTR-276 rock triaxial test system.
Fig 14.
Process curve of rock uniaxial compression in the -570m level of Sizhuang mining area.
Table 4.
Uniaxial compression test results of the -570m level rock.
Table 5.
Rock classification summary.
Table 6.
Results of three-layer.
Table 7.
Results of four-layer.
Fig 15.
Stope investigation (a)Stope investigation; (b)Work face of three-layer; (c)Work face of four-layer.
Fig 16.
Stope failure in four-layer (a) Bolt support failure; (b) Roof Caving; (c) Cracking of side concrete; (d) Roof concrete caving.