Research on the Effect of Water Draining Through Vertical Drainage Systems in the Process of Soil Consolidation
Keywords:consolidation, drainage, pore pressure, settlement.
A saturated soil subjected to a growing total effort will reduce gradually the volume up to excess pore water pressure dissipation, interfering primary consolidation. This process can take a long time and when all excess pressure is dissipated, the soil is considered consolidated.
In low permeability soils, from external loading, results in an increase of the normal effort at higher values than the earth preconsolidation pressure, thus having neutral increased pressure followed by a consolidation process where water is expelled from the pores of the soil. The decrease in porosity (soil volume), so produced, is accompanied by a gradual increase of effective pressure and a corresponding decrease in excess pore water pressure. The consolidation process continues until the excess pore water pressure dissipates only complete and upload translates into effective stress. Duration of the process depends on the consolidation characteristics of the soil and drainage ways (with how much drainage paths are longer, the longer is the process of consolidation). The purpose of installing vertical drains is to shorten the drainage ways and time needed to dissipate the neutral pressure. The time to dissipate the excess water pressure in the pores (time consolidation) is so short as the inter-distance between the drains is less.