JLab
What JLab is for, the assumptions used by the app, and how stress units are handled.
All apps require a verified JWGeotech account and acceptance of the current Terms. Opening or reloading the app requires an internet connection to verify sign-in. An already authenticated tab can continue through temporary outages until its verified session expires; Browser and Native solving in JSlope and JRunout retain their licence requirements. Sign-out or session expiry locks the workspace and retains unsaved work in the tab. Signing in does not upload local project files.
Open JLab to compare rock strength and calibrate materials after signing in with a free account.
JLab is a browser-based geotechnical calculator for inspecting rock and discontinuity strength envelopes. It plots principal-stress and normal/shear envelopes, calibrates selected strength parameters from pasted test data, and summarizes derived rock-mass quantities.
Engineering-use disclaimerJLab is a calculation and visualization aid. It is not a substitute for project-specific design checks, laboratory data review, ground model validation, numerical modelling, or qualified engineering judgment.
Stress Sign Convention
Compression is treated as positive. Internally, stress values are stored in MPa. The stress unit selector changes displayed values and editable stress fields between MPa and kPa without changing the stored engineering state.
| Area | Convention |
|---|---|
| Principal stress plot | x = minor principal stress sigma3; y = major principal stress sigma1. |
| Normal/shear plot | x = normal stress sigma_n; y = shear strength tau. |
| Calibration data | Rows are interpreted using the active stress unit at the time values are entered. |
| CSV export | Rows include material identity, criterion, series, and stress values in the active unit. |
Supported Strength Criteria
- Mohr-Coulomb: linear shear strength envelope.
- Generalized Hoek-Brown: nonlinear rock-mass strength criterion.
- Power Curve: nonlinear normal/shear envelope.
- Barton-Bandis: nonlinear rock joint/discontinuity envelope.