Estimate stress using depth, surcharge, and water conditions. Switch between manual and automatic input methods. Get clear results, export reports, and verify ground behavior.
The calculator uses the effective stress equation:
σ′ = σv − u
Here, σ′ is effective stress, σv is total vertical stress, and u is pore water pressure.
Total stress is found from surcharge and layer self-weight:
σv = q + Σ(γ × h)
For soil above the water table, the moist unit weight is used. For soil below the water table, the saturated unit weight is used.
Hydrostatic pore pressure is estimated with:
u = γw × hw
Where γw is water unit weight and hw is the depth below the water table. If measured pore pressure is available, the calculator uses that value directly.
| Case | Depth (m) | Water Table (m) | Total Stress (kPa) | Pore Pressure (kPa) | Effective Stress (kPa) |
|---|---|---|---|---|---|
| Profile A | 3.00 | 2.00 | 66.00 | 9.81 | 56.19 |
| Profile B | 5.00 | 2.00 | 106.00 | 29.43 | 76.57 |
| Profile C | 6.50 | 1.50 | 139.50 | 49.05 | 90.45 |
| Manual D | 5.00 | Field Read | 120.00 | 45.00 | 75.00 |
Effective stress is one of the most useful ground response indicators. It describes the share of total stress carried by soil grains. That grain-to-grain contact controls strength, settlement, and volume change. A higher value usually means stronger confinement. A lower value can mean soft behavior, reduced stiffness, or uplift risk. Engineers, researchers, and students use effective stress to understand how water and soil interact below foundations, retaining systems, embankments, and excavations.
Total stress alone never tells the full story. Water inside pores creates pressure that supports part of the load. That pressure reduces the force transferred between particles. The calculator therefore separates total stress from pore pressure. It also tracks the water table depth and hydrostatic head. This makes the output more realistic for layered soil, shallow groundwater, and surcharge loading. Measured pore pressure can also replace the hydrostatic estimate when monitoring data exists.
Real ground conditions rarely have one uniform unit weight. Surface fill, silty sand, clay, and dense bearing layers often appear in sequence. The layered input method handles that variation clearly. Each layer can use a moist unit weight above the water table and a saturated unit weight below it. That gives a better stress profile at the selected depth. It also helps compare different soil configurations during feasibility reviews and preliminary design checks.
The result panel shows overburden stress, surcharge, total stress, pore pressure, and final effective stress. It also lists the effective stress ratio and a short interpretation note. Use the layer summary table to verify each contribution. Export the result to CSV for calculations and to PDF for reports. This workflow supports faster checking, cleaner documentation, and more confident decisions during soil physics and ground pressure evaluations.
Effective stress is the portion of total stress carried by soil particles. It equals total vertical stress minus pore water pressure.
The water table controls pore pressure. As depth below the water table increases, pore water pressure rises and effective stress changes.
Yes. Negative values can appear during uplift, seepage, or inconsistent input assumptions. They usually need review before design use.
Use meters for depth, kN/m³ for unit weight, and kPa for stress and pore pressure. The output remains consistent with those units.
Use manual mode when field instruments, lab reports, or previous calculations already provide total stress and pore pressure values.
Yes. Surcharge increases total stress at depth. If pore pressure stays unchanged, effective stress rises by the same amount.
Yes. The automatic mode supports three layers and applies moist or saturated unit weights depending on water table position.
CSV helps with spreadsheets and comparison studies. PDF helps with documentation, review notes, and project submission records.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.