Geotextiles in reclamation projects fulfill two primary purposes:
Separation: They create a distinct boundary between the reclamation fill material and the underlying marine mud. This prevents intermixing, ensuring the fill remains stable and the underlying soft mud does not compromise the reclamation’s integrity.
Reinforcement (Debatable): Geotextiles can potentially act as reinforcement to enhance the stability of the reclaimed land. However, this function is a subject of ongoing debate, as its effectiveness depends on various factors. The directional strength of woven geotextiles and potential damage caused by vertical band drain installation are crucial considerations in assessing their reinforcing capabilities.
Sand, on the other hand, plays two essential roles:
Load Distribution: The sand layer effectively distributes the load of the subsequent public fill, ensuring it is evenly spread over the underlying ground. This prevents localized stress concentrations and minimizes the risk of settlement or instability.
Drainage: Sand acts as a permeable drainage path, allowing for the dissipation of excess pore water pressure generated during the consolidation of the underlying marine mud. This is particularly important when vertical band drains are installed, as the sand layer facilitates the efficient removal of water, accelerating the consolidation process and promoting the stability of the reclaimed land.