Mined tunnel designer ⛏️

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

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

Mining design full calculation

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