Mined Tunnel Design Calculator
Automatically generate a concept SCL mined tunnel design using the RMR 89, RMR 14 and Q method for rock mining.
Input tunnel geometry
This tool is intended for an estimate and cannot replace any design.
Excavation span
m
Enter a number between 0 & 25.
Rock UCS
MPa
Enter a number between 0 and 400.
Joint spacing
mm
Enter a number between 0 and 2,000.
Joint conditions:
Water ingress:
Joint orientation:
Mining concept design summary
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| Rock class | - |
| Rock mass rating | - |
| RQD | -% |
| Unsupported stand-up time: | - |
| Min. SCL thickness | - |
| Min Rock bolt length | - |
| Rock bolt spacing | - |
| Construction sequence | - |
| ESR value | |
| Rock class | test |
| Q rating | test |
| RQD | -% |
| Tunnel support details | Fibre reinforced shotcrete and bolting |
| Min Rock bolt length | -m |
| Rock bolt spacing in shotcreted areas | m |
| Rock bolt spacing in unshotcreted areas | -m |
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RMR 14 to Q Method Correlation
To correlate RMR 14 and the Q method rating, 101 representative cases were assessed and presented in the book 'Ground Characterization and structural analyses for tunnel design' by Celada et al (2020).
RMR 14 rating:
Q Method rating:
RMR 89 to RMR 14 Correlation
RMR 14 can be correlated to RMR 89 using the method presented in the book 'Ground Characterization and structural analyses for tunnel design' by Celada et al (2020). Whereby mapping of 2,298 tunnel faces was used to correlate the two ratings.
RMR 89:
RMR14:
RMR 89 Calculation
The RMR rating is calculated by summing the rating from the following five parameters. These parameters are calculated used the empirical charts shown below, presented by Bieniawski in 1973.
| Category | RMR Score |
|---|---|
| UCS of intact rock | - |
| Discontinuity spacing | - |
| RQD | - |
| Discontinuity condition | - |
| Water ingress | - |
| Joint orientation | - |
| - |
Rock UCS chart
UCS: MPa
UCS RMR score:
Joint spacing chart
Avg. joint spacing: mm
Joint spacing RMR score:
Discontinuity & RQD correlation
Avg. joint spacing: mm
RQD: %
RQD Chart
RQD: %
RQD RMR score:
Discontinuity condition
| Condition of discontinuity | RMR |
|---|---|
| Very rough surfaces, no separation, unweathered walls | 30 |
| Slightly rough surfaces, separation <1mm, slightly weathered walls | 25 |
| Slightly rough surfaces, separation >1mm, highly weathered walls | 20 |
| Slicken sided sufaces, seperation 1-5mm continuous | 10 |
| Seperation >5mm continuous | 0 |
Water ingress
| Ground water condition | RMR |
|---|---|
| Completely dry, no inflow per 10m tunnel length | 15 |
| Damp, <10litres/min per 10m tunnel length | 10 |
| Wet, 10-25litres/min per 10m tunnel length | 7 |
| Dripping, 25-125litres/min per 10m tunnel length | 4 |
| Flowing, >125litres/min per 10m tunnel length | 0 |
Joint Orientation
| Joint orientation adjustment | RMR |
|---|---|
| Strike perpendicular to tunnel axis. Excavation with dip (45-90°) | 0 |
| Strike perpendicular to tunnel axis. Excavation with dip (20-45°) | -2 |
| Strike perpendicular to tunnel axis. Excavation against dip (45-90°) | -5 |
| Strike perpendicular to tunnel axis. Excavation against dip (20-45°) | -10 |
| Strike parallel to tunnel axis. Excavation against dip (45-90°) | -12 |
| Strike parallel to tunnel axis. Excavation against dip (20-45°) | -5 |
| Dip of 0-20° in any direction | -5 |
