DOI: 10.5593/SGEM2016/B13/S02.029


F. Pascariu
Tuesday 6 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-57-5 / ISSN 1314-2704, June 28 - July 6, 2016, Book1 Vol. 3, 229-236 pp

Regularly, in Geotechnics domain the superficial deposits from Iasi (Romania) are associated with Quaternary age and bedrock with Sarmatian. There are situations when this rule does not apply, especially when clays are not containing any fauna, just like the case of some samples collected from Palas area, Iasi.
This study aims to establish the boundary between the oldest formation and more recent ones, from their geotechnical characteristics. The research was carried out based on the physical and mechanical parameters obtained in the laboratory. The clay samples were collected from geotechnical wells from Palas area, Iasi.
The elaboration of this study followed three steps. The first step was to plot the parameters (humidity, plasticity, porosity, compaction and cohesion) inside variation charts, against depth. Then, it could be observed a dependency on depth of these parameters and, based on that, a separation in zones was made. The third step was the determination of the statistic values of the physical and mechanical properties. This was done order to compare the parameters obtained in the previous stage, already separated in zones. Statistical analysis was performed in accordance with STAS 3300-85, for each of the mentioned parameters.
The results show that the analysed perimeter from Iasi can be separated, against depth, into two zones with clay having different characteristics: an area with physical and mechanical characteristics less favourable (at the top) and an area with more favourable characteristics, underneath it. The boundary between the two areas is at 10 m below surface. The layers above this boundary are shallow formations. Below the boundary we can find the bedrock formation. Although, it has been observed few clay samples parameters with no clear connection to one of the two formations. Regarding the clay cohesion values, they are not following a certain trend, so no conclusion could be made on it in the both types of deposits. As a final consideration, the separation by age (Sarmatian from Quaternary), using geotechnical parameters, cannot be made clearly in this area. Other methods of separation will be applied in the next projects.

Keywords: clays, geotechnical analysis, shallow deposits, bedrock