Presets
Playback
Soil, climate and water
Cold at the top freezes the pore water; where water can be drawn up from below, it freezes in lenses and pushes the ground up.
Model checks
The science
What is modelled
A one-dimensional column of 60 cells. The enthalpy of each cell holds both sensible and latent heat, so freezing happens over a narrow temperature band. At the front, water drawn up by cryosuction freezes into an ice lens, limited by Darcy-type supply and by the cold-side cooling power.
Equations
- Heat flux
q = k dT/dzwith conductivity raised by 24 % per unit ice fraction. - Enthalpy balance
dE/dt = -dq/dz, latent steprho_w n S L. - Steady frost depth from equal fluxes
1.24 k (0 - Ts) / z = k (Tb - 0) / (H - z). - Ice of volume
rho_w / rho_i = 1.0905times the water drawn up.
Checks run in the page
- Temperature to enthalpy and back.
- Energy conservation against the boundary fluxes.
- Frost depth after 35 days against the flux balance.
- Lens volume against the water drawn up, pore-ice formula and the flux cap.
Honest simplifications
A reduced-order model: the lens growth rule, the 24 % conductivity increase, the 0.09 pore-ice expansion factor and the 18 mm/day cap are educational choices, not calibrated to a soil; no overburden, salt or lateral flow.
What to try
- Press Clay and compare with Sand: strong suction but slow water supply against the opposite.
- Press Silt without groundwater: the heave nearly stops.
- Lower the surface temperature and watch the front reach the steady depth shown in the last plot.