This low preconsolidation pressure suggests there was insufficient time for dissipation of excess pore-water pressure created by thickening of the advancing glacier. Cette faible pression de préconsolidation suggère qu'il n'y eut pas suffisamment de temps pour assurer une dissipation complète de l'excédent de pressions interstitielles résultant de l'épaississement des glaciers en progression. Keeping in mind that positive z is downwards, we start from the top of the soil sample. The change in pore water pressure from the surface is. Adding the pore water pressure at the soil's upper surface yields u = 4.9 + 26.95 = 31.85 kPa. The total stress at this point is. The effective stress is simply 33.4 - 31.85 = 1.55 kPa.
The temperature gradient is smaller and the excess pore pressure gradient is more negative in areas of thinner sediment. This correlation is explained by postulating downward pore water advection within the sediments, with flow velocities on the order of 10−9 to 10−8 m/s in the thinnest sediments and much less flow in the thickest sediments.
As a result, the pressure in the seawater pushes water molecules into a reservoir of pure water. If performed by someone with a few rudimentary tools and a knowledge of how to provide just the right amount of pressure, it is possible that reverse osmosis could save the life of a shipwreck victim stranded in a location without a fresh water supply.