Review of formula for consolidation with prefabricated vertical drains, for a project

The consolidation settlement of soft clay subsoil creates a lot of problems in foundation and infrastructure engineering. Because of the very low clay permeability, the consolidation process takes a longer time for completion. To shorten this consolidation time, vertical drains are installed together with or without preloading by surcharge embankment or vacuum pressure. This accelerated consolidation process leads to increase in shear strength of soil. Prefabricated Vertical Drains are artificially-created drainage paths which can be installed with the help of rig mounted with crawler equipment. The formula available is used to estimate the time required to achieve certain degree of consolidation with PVD. This paper reviews formulas use at design stage to predict the realistic output. Paper also includes, solved examples based on actual site parameters with stage wise consideration.