Rock Mass Rating (RMR) Calculator
Input Parameters
Range: 0-250 MPa. Higher values indicate stronger rock. Typical values: Very weak rock (0-1 MPa), Weak rock (1-5 MPa), Medium strong rock (25-50 MPa), Strong rock (50-100 MPa), Very strong rock (100-250 MPa).
100 MPa
Score: 12
Percentage of intact rock pieces longer than 10 cm in a drill core. Range: 0-100%. Classification: Very poor (0-25%), Poor (25-50%), Fair (50-75%), Good (75-90%), Excellent (90-100%).
75%
Score: 13
Distance between adjacent joints. Typical values: Very close (<1 cm), Close (1-3 cm), Moderate (3-10 cm), Wide (10-30 cm), Very wide (>30 cm).
30 cm
Score: 10
Description of joint surface characteristics and filling material. Consider roughness, weathering, separation, continuity, and infilling materials.
Score: 20
Description of water flow through discontinuities. Consider both natural conditions and effects of excavation.
Score: 10
Adjustment based on the relationship between joint orientation and excavation direction. Consider strike and dip relative to the engineering structure.
Score: -5
Results
81
VERY GOOD ROCK
1. Uniaxial Compressive Strength
12
2. Rock Quality Designation (RQD)
13
3. Joint Spacing
10
4. Joint Condition
20
5. Groundwater Conditions
10
6. Joint Orientation Adjustment
-5
Total RMR Score
60
Rock Mass Classification:
81-100: Very Good Rock
61-80: Good Rock
41-60: Fair Rock
21-40: Poor Rock
0-20: Very Poor Rock
Generating PDF report…
Rock Mass Rating (RMR) Calculator
Rock Mass Rating (RMR) Calculator