Prefabricated drain board/vertical wick drains installation

Prefabricated Vertical Drain (PVD) is a modern technique of installing a vertical drain of polyester for improving the soil properties to strengthen the soil in reclamation bed, coastal areas and marshy area where soft clay is encountered at much more depth. Installation of PVD and placing a calculated amount of surcharge fill causes the subsoil to consolidate as per “Terzhaghi’s Theory of Consolidation”. In natural consolidation with application of surcharge fill alone, it may take more than 50 to 90 years and even much more depending upon soil condition to achieve 90% consolidation where as the bed treated with PVD with surcharge fill accelerates the process of consolidation to attain the maximum settlement within short period of time. The process involves installation of prefabricated drain in the week soil and application of calculated surcharge load to squeeze out the water through the inserted drains during the waiting period. The relative advantages of PVD over Sand Drains are

i) PVD is relatively cheaper than Sand Drains.
ii) Fast Installation Method of PVD helps to reduce the time of Completion.

Prefabricated drain board/vertical wick drains installation