Geology Geomechanics Mohr Coulomb Cohesion From Hoek Brown Calculator
FIT equivalent MC cohesion/friction over independently chosen confinement-window sampled Hoek–Brown envelope, not universal mapping or exact nonlinear envelope. Caller independently establishes matching units, evidence, method edition and applicability; output is not compliance, diagnosis, work-safety approval, geological identity or validated hazard prediction.
Description
An equivalent Mohr–Coulomb envelope can be fitted over a selected confining-stress interval.
An equivalent Mohr–Coulomb envelope can be fitted over a selected confining-stress interval.1
The resulting cohesion and friction angle describe that fitted interval rather than a complete nonlinear Hoek–Brown failure envelope. Use this tool to calculate geomechanics mohr coulomb cohesion from hoek brown from the supplied measurements and assumptions.
When to use Geology Geomechanics Mohr Coulomb Cohesion From Hoek Brown Calculator
Use this tool to calculate geomechanics mohr coulomb cohesion from hoek brown from the supplied measurements and assumptions. Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
How to use Geology Geomechanics Mohr Coulomb Cohesion From Hoek Brown Calculator and understand its results
- Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
- Enter independentlySampledHoekBrownSigma3, matchedHoekBrownSigma1, using the field meanings and rules below, then run the tool.
- Read fittedCohesion, fittedFrictionAngleDegrees, fitRSquared. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| independentlySampledHoekBrownSigma3 | Independently sampled hoek brown sigma3; caller assertion or measurement requiring independent evidence | list of number | Required |
| matchedHoekBrownSigma1 | Matched hoek brown sigma1 | list of number | Required |
Fit matched sigma1 versus sigma3 values by ordinary least squares, requiring at least two observations and nonzero predictor variance. Require slope≥1 and intercept≥0. Convert the line to cohesion=intercept/(2√slope) in the input stress unit and friction angle=asin((slope−1)/(slope+1)) in degrees; also return R². The tool does not generate Hoek–Brown samples or select their confining-stress range.
cohesion=intercept/(2√slope); frictionDeg=asin((slope−1)/(slope+1))×180/π Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| fittedCohesion | Fitted Cohesion; follow the units, sign, ordering and evidence convention stated above | number |
| fittedFrictionAngleDegrees | Fitted Friction Angle Degrees; follow the units, sign, ordering and evidence convention stated above | number |
| fitRSquared | Fit R Squared; follow the units, sign, ordering and evidence convention stated above | number |
{
"input": {
"independentlySampledHoekBrownSigma3": [
0,
1,
2
],
"matchedHoekBrownSigma1": [
2,
5,
8
]
},
"output": {
"fittedCohesion": 0.5773502691896258,
"fittedFrictionAngleDegrees": 30.000000000000004,
"fitRSquared": 1
}
}Limitations and assumptions
The resulting cohesion and friction angle describe that fitted interval rather than a complete nonlinear Hoek–Brown failure envelope. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Geology Geomechanics Landslide Factor Of Safety Janbu Calculator for this related task: A Janbu simplified analysis balances forces for independently specified slices of a potential slip mass.
Use Geology Seismic Stress Drop Calculator when its separate inputs and assumptions fit the question: An idealized circular rupture model relates seismic moment and rupture radius to a stress-drop estimate.
References
Similar or alternative tools
- Geology Geomechanics Landslide Factor Of Safety Janbu Calculator
A Janbu simplified analysis balances forces for independently specified slices of a potential slip mass.
- Geology Seismic Stress Drop Calculator
An idealized circular rupture model relates seismic moment and rupture radius to a stress-drop estimate.