The study is focused on the increasing transition from laboratory soil testing to advanced in-situ methods, which is particularly relevant due to the difficulty of obtaining undisturbed natural samples for large-scale engineering projects. At the same time, laboratory investigations remain essential for scientific research and calibration of field data. The main objective of the work was to describe the operation principles, measurement capabilities, and practical applications of the Marchetti Flat Dilatometer (DMT), as well as to present the upgraded Seismic Dilatometer Marchetti (SDMT) equipped with a module for measuring shear wave velocity (Vs). The research methodology included experimental field measurements, observational studies, and comparative analysis supported by data interpretation techniques. These methods allowed obtaining reliable and practically significant information on soil behaviour underload. The results demonstrate that the Marchetti dilatometer is suitable for testing a wide range of soil types, from loose and soft clays to dense sands and soft rocks. DMT provides stable and accurate results even in very soft or highly over-consolidated soils. The obtained parameters can be effectively used for prediction of foundation settlement, evaluation of compaction quality, assessment of cyclic liquefaction resistance, and control of geotechnical improvement processes. The introduction of the seismic module considerably expands the capabilities of the device, allowing simultaneous determination of shear wave velocity and stiffness parameters crucial for seismic site characterization. Correlations established between DMT indices, deformation modulus, and liquefaction resistance confirm the applicability of DMT/SDMT data for integrated geotechnical and seismic analyses. The study concludes that the Marchetti dilatometer, especially in its seismic modification, is an efficient and informative tool for field soil investigations, offering a reliable basis for engineering decision-making in design, monitoring, and ground improvement quality control.
Zhamek et al. (Thu,) studied this question.