Vertical pore pressure variations and geotechnical sediment properties at a sandy beach

The role of geotechnical properties and soil behavior for beach dynamics has been recognized before, but field measurements in energetic environments are still rare. This study focused on two days along a cross-shore transect reaching from the foot dunes to upper subtidal zone at western sandy island Sylt, Germany, just south city Westerland. Sediment parameters were obtained sediment sampling limited in-situ testing. Pore pressure conducted vertical array 55 cm surface lower intertidal zone. recordings then analyzed using one-dimensional-vertical (1DV) model based Biot (1956) Mei Foda (1981). Laboratory testing results demonstrated slight trends increasing grain size friction angles subaerial In-situ strength portable free fall penetrometer supported Additionally, significant increase resistance was observed swash showed consistent trend associated with tidal water elevations. However, data collected during low tide suggested decoupling effects groundwater, possibly gas content negative pore pressures vadose also more pronounced wave damping layers minor phase lag. 1DV succeeded simulate all depths well, no liquefaction events measurement period, reduction effective weight that may affect dynamics.