Compare upward and downward ground movement with clear project inputs. Review differential risk, trends, limits, and support better foundation decisions.
| Case | Thickness (m) | Δe | Heave Strain (%) | Adopted Heave (m) | Adopted Settlement (m) | Net Movement (m) |
|---|---|---|---|---|---|---|
| Warehouse Slab | 4.00 | 0.12 | 1.50 | 0.060 | 0.267 | -0.207 |
| Light Industrial Pad | 3.50 | 0.08 | 1.10 | 0.039 | 0.156 | -0.117 |
| Expansive Soil Strip Footing | 2.80 | 0.04 | 2.20 | 0.062 | 0.062 | 0.000 |
Settlement from void ratio change:
S = H × (Δe / (1 + e₀))
Heave from strain:
Hh = H × (εh / 100)
Heave from swelling index:
Hs = H × Cs × log10(σ′0 / σ′f)
Net movement:
Net Movement = Adopted Heave − Adopted Settlement
Differential check:
Absolute Differential = |Net Movement|
Movement ratio:
Movement Ratio = Reference Span / Absolute Differential
This page compares upward soil expansion against downward compression. It helps identify the governing movement and whether the differential value exceeds the project limit.
Heave and settlement both change the level of a foundation. They come from different soil responses. Settlement usually follows loading, consolidation, or densification. Heave often follows unloading, swelling, frost action, or moisture expansion in active soils.
A comparison calculator is useful because design teams rarely face only one movement mode. Many sites have seasonal moisture swings, excavation effects, fill placement, and variable groundwater. One zone may rise while another moves downward. That creates distortion, cracking, and serviceability problems.
This calculator combines several practical inputs. It uses void ratio change to estimate settlement. It uses strain and swelling index to estimate possible heave. Then it compares the two responses and shows net movement, absolute differential, and a simple movement ratio for quick review.
The adopted heave can come from either strain or swelling behavior. The adopted settlement can come from the compression estimate or a manual override from a detailed geotechnical study. This makes the page flexible for concept design, checking reports, and comparing field scenarios.
Engineers should still validate assumptions with proper site data. Soil layering, drainage, desiccation depth, stress history, and structural stiffness all affect performance. A stiff raft may tolerate localized movement differently than a strip footing or lightly reinforced slab.
Use the result as a screening tool. When the differential value approaches or exceeds the allowable limit, a deeper review is sensible. That may include lab swell tests, consolidation testing, groundwater assessment, moisture control planning, and structural detailing adjustments.
It compares estimated upward heave against downward settlement. The result helps you see which movement governs and whether the net differential may create serviceability concerns.
Use it when you already have adopted values from testing, monitoring, or a geotechnical report. The override lets you compare final design assumptions without changing the rest of the input set.
Void ratio change is a practical compression measure in soil mechanics. It links the change in soil structure to vertical deformation over the affected thickness.
Projects may have different data sources. Some teams know expected swell strain. Others have unloading data and a swelling index. Showing both methods makes comparison easier.
Net movement is adopted heave minus adopted settlement. A positive result means upward movement dominates. A negative result means downward movement dominates.
No. It is best used for screening, comparison, and preliminary checks. Final design should include project-specific geotechnical interpretation and structural review.
It gives a quick sense of distortion over a reference span. A smaller ratio usually indicates more severe differential movement effects.
Yes. It is useful for expansive soil reviews, especially where moisture variation or unloading may cause uplift. Still, confirm input values with reliable testing.
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.