Question:

A certain coal mine has a weak layer comprising of 10cm, 11cm, 9cm, 12cm, 15cm, and 19cm of interlaminated shales and mudstone. Design a full column resin bolt support system if the weak layer is overlain by 70cm of sandstone.

Given:

• Hole diameter: 28mm
• Bolt diameter: 20mm
• Bolt tensile strength: 500MPa
• Sandstone tensile strength: 6MPa
• Bord width: 6m
• Resin rock interface shear resistance: 2.5MPa

Also determine the reasonable cut-out distance.