DETERMINING STABILIZATION TIME OF VIBRATING WIRE PIEZOMETERS IN LOW-PERMEABILITY MORAINE SOILS

This study investigates the stabilization behavior of diaphragm-type vibrating wire piezometers installed in low-permeability moraine soils during the staged construction of a railway embankment in Lithuania. Reliable determination of stabilization time is essential for interpreting pore water pressure data and distinguishing installation-related effects from actual hydrological or structural responses. Four piezometers were installed at depths of 1 m and 5 m using the sand pack method. The sensors demonstrated stabilization within a few days, with shallow piezometers responding to rainfall within hours and deeper piezometers exhibiting slightly delayed but consistent trends. The data confirmed that subsequent pressure changes were linked to rainfall, groundwater fluctuations, and embankment loading, rather than delayed sensor response. The results indicate that diaphragm-type piezometers, when properly installed, are suitable for reliable short-term monitoring in moraine environments. This paper provides practical insights for defining stabilization periods in low-permeability soils and supports confident use of piezometric data in design and analysis.