The Behavior of Flow Condition in Prefabricated Vertical Drains Due To Incremental Confining Pressure

Prefabricated Vertical Drains (PVDs) are commonly used in geotechnical engineering to speed the consolidation of soft and compressible soils. Understanding the behavior of PVDs under various load conditions is essential for their efficient design and implementation. This research aims to improve the performance and efficacy of PVD systems in geotechnical engineering applications by investigating and comprehending the behavior of flow conditions in PVDs under incremental confining pressure. Three PVD samples varying in thicknesses have been evaluated in the laboratory to determine their discharge capacity and transmissivity under various hydraulic gradients. The PVD was subjected to incremental confining pressures between 50 and 200 kPa. The apparatus utilized in this study was designed by following ASTM D4716. The flow condition was determined by limiting the hydraulic gradients and calculating the turbulence degree of the flow. The analysis results showed that the flow inside PVD is non-laminar, and the PVD with the larger cross-section is more resilient to deviations in the hydraulic gradient. The proposed equations accurately predicted the discharge capacity of PVDs under increasing confinement pressures, and a comparison with experimental results revealed a high level of concordance. Particularly for PVDs with larger cross-sectional areas, the hydraulic gradient significantly affected the discharge capacity.