Geology Geomechanics Landslide Factor Of Safety Janbu Calculator
Bounded positive-branch Janbu simplified slice equilibrium with independent correction factor, pore pressure/friction actual slice evidence; not a Bishop formula renamed or slope safety certification. 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
A Janbu simplified analysis balances forces for independently specified slices of a potential slip mass.
A Janbu simplified analysis balances forces for independently specified slices of a potential slip mass.1
Geometry, loads, pore pressures and a correction factor are external model inputs; a numerical root alone does not establish slope safety. Use this tool to calculate geomechanics landslide factor of safety janbu from the supplied measurements and assumptions.
When to use Geology Geomechanics Landslide Factor Of Safety Janbu Calculator
Use this tool to calculate geomechanics landslide factor of safety janbu 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 Landslide Factor Of Safety Janbu Calculator and understand its results
- Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
- Enter sliceWidths, sliceWeights, porePressures, cohesions, frictionRadians, baseRadians, independentJanbuCorrection, using the field meanings and rules below, then run the tool.
- Read janbuSimplifiedFactor, equilibriumResidual. 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 |
|---|---|---|---|
| sliceWidths | Slice widths | list of number | Required |
| sliceWeights | Slice weights | list of number | Required |
| porePressures | Pore pressures | list of number | Required |
| cohesions | Cohesions | list of number | Required |
| frictionRadians | Friction radians | list of number | Required |
| baseRadians | Base radians | list of number | Required |
| independentJanbuCorrection | Independent janbu correction | number | Required |
Enter 1–128 aligned slices with positive widths and weights, nonnegative pressures and cohesion, 0≤friction<π/2 and |baseAngle|<π/2, plus a positive correction factor. Require positive Σ(weight×tan(baseAngle)) and nonnegative effective load weight−pressure×width. For trial F use denominator cos²(alpha)×(1+tan(alpha)tan(phi)/F), requiring the positive branch. Bracket a root above any denominator singularity between the stated 1e−6 and 1e6 limits; an unresolved bracket fails. Perform 120 bisection iterations and return F plus its equilibrium residual. Width, force and stress units must be mutually consistent, such as per-unit out-of-plane thickness. No slip-surface search or stability approval occurs.
residual(F)=correction×Σ[(cohesion×width+(weight−pressure×width)tan(phi))/(cos²(alpha)(1+tan(alpha)tan(phi)/F))]−FΣweight tan(alpha) Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| janbuSimplifiedFactor | Janbu Simplified Factor; follow the units, sign, ordering and evidence convention stated above | number |
| equilibriumResidual | Equilibrium Residual; follow the units, sign, ordering and evidence convention stated above | number |
{
"input": {
"sliceWidths": [
1
],
"sliceWeights": [
1
],
"porePressures": [
0
],
"cohesions": [
1
],
"frictionRadians": [
0
],
"baseRadians": [
0.7853981633974483
],
"independentJanbuCorrection": 1
},
"output": {
"janbuSimplifiedFactor": 1.9999999999999996,
"equilibriumResidual": 2.220446049250313e-16
}
}Limitations and assumptions
Geometry, loads, pore pressures and a correction factor are external model inputs; a numerical root alone does not establish slope safety. 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 Mohr Coulomb Cohesion From Hoek Brown Calculator for this related task: An equivalent Mohr–Coulomb envelope can be fitted over a selected confining-stress interval.
Use Geology Landslide Volume Calculator when its separate inputs and assumptions fit the question: Differencing aligned pre-event and post-event surface heights gives signed change within each measured cell.
References
Similar or alternative tools
- Geology Geomechanics Mohr Coulomb Cohesion From Hoek Brown Calculator
An equivalent Mohr–Coulomb envelope can be fitted over a selected confining-stress interval.
- Geology Landslide Volume Calculator
Differencing aligned pre-event and post-event surface heights gives signed change within each measured cell.