Analysis of settlements in soft soils can be calculated by analytical or numerical methods. Both require geomechanical parameters that can be obtained either with a well planned program of laboratory research or in-situ research, or a combination of both. Two tests are usually used in the Slovenian geotechnical profession to determine the characteristics of soils: the cone penetration test (CPT) and the flat dilatometer test (DMT). The principal purpose of both tests is to classify the soils and determine, through empirical corrections and theoretical background, their layering, deformation characteristics and porosity. Both tests were performed to determine the strength and deformation characteristics of the ground in Sinja Gorica na Vrhniki, where the construction of a new commercial facility is predicted. The ground plan dimensions of the structure are 50 m x 16,7 m. Fieldwork measurements showed that the soil structure of the analysed area are soft soils with organic matter that reach up to 14 meters in depth. Shallow foundations, without preloaded embankment, was not adequate on this location since to the weight/load exceeds the bearing capacity of the ground. Thus, following the examination of the designer, a 3,4 meters high preloaded embankment was built with gravel columns of cca 70 cm in diameter and 14 m in length. The monitoring of settlements of preloaded embankment was implemented using digital inclinometer. As part of the research work and the direct and back analysis using the program PLAXIS 2D were carried out. The analyses showed that the calculated settlements are some 30% higher than those measured on the field. It can be concluded from the back analyses that geomechanical parameters, which were defined using the cone penetration and the flat dilatometer tests, are on a safe side as the parameters calculated from the back analyses provide with some 40% to 50% higher values than the measured ones.
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