Why use PVD over sand drain

Why use PVD (Prefabricated vertical drain) over sand drain

• Installation of PVDs typically 6,000 linear meters per day (depending on the soil and the machine used it changes from 2000 to 8000) and result in a lower project cost.
• No (or less) risk of PVDs breaking during installation - sand drains can have discontinuities if mandril is withdrawn too fast.
• No (or less) risk of shear failure of PVDs during settlement - sand drains are vulnerable to shear failure during settlement.