Šujan M., Slávik I., Galliková Z., Dovičin P. & Šujan M., 2016: Pre-Quaternary basement of Bratislava (part 1): genetic vs. geotechnical characteristics of the Neogene foundation soils. Acta Geologica Slovaca, 8, 1, 71–86.

Pre-Quaternary basement of Bratislava (part 1): genetic vs. geotechnical characteristics of the Neogene foundation soils

Martin Šujan¹, Ivan Slávik², Zuzana Galliková², Peter Dovičin³ & Michal Šujan⁴

¹EQUIS, spol. s r. o., Račianska 57, 831 02 Bratislava; mato@equis.sk
²Department of Geotechnics, Faculty of Civil Engineering, Slovak University of Technology, Radlinského 11, 810 05 Bratislava; ivan.slavik@stuba.sk, zuzana.gallikova@stuba.sk
³Geotechnická spoločnosť – GES, s. r. o., Lamačská cesta 8, 811 04 Bratislava; geo-ges@orangemail.sk
⁴Department of Geology and Palaeontology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava; miso@equis.sk

Abstract

The foundation soils of the majority of complicated buildings (or high-rise structures) in the Bratislava urban area are formed by the Neogene sediments, situated below the Quaternary cover. These are prevailingly high-rise buildings founded in the deep foundation pits. This contribution is focused on the analysis of the possible relations between the sediments origin and their geotechnical parameters (properties). The introductory part of the analysis was carried out on the model profile situated at the left bank of the Danube River, where the construction of high-rise buildings containing underground part was concentrated recently. The analysis was oriented on the characteristic of the pre-Quaternary basement surface morphology, geologic structure up to the reach of the exploration works and substantial geotechnical characteristics of the foundation soils. The analysis comprised comparison of geotechnical properties of the Neogene cohesive subsoils of the pre-Quaternary basement on the localities with predicted occurrence of genetically different lithostratigraphic formations. The sedimentological and geotechnical characteristics of foundation soils of the Neogene complex formed the baseline data of the analysis. The geotechnical data were taken from the engineering geological tasks realized by the authors of this study. The results of the analysis point out on the mutual affinity of the foundation soil properties, belonging to the Beladice Fm. (deltaic sequence) and Volkovce Fm. (alluvial sequence). The geostatic pressure (pressure of the superposed layers) existing during the entire period of their burial in the profile have had the dominant influence on the actual geotechnical parameters (geological pre-consolidation). This effect overwhelms the differences in the subsoils properties, which could be determined by the facies character related to their origin. Studied sedimentary formations differ in lateral stability: the Volkovce Fm. exhibits much higher lateral lithological heterogeneity than Beladice Fm., what could affect a construction site conditions. Due to the relatively massive input data files, the results of the analysis can serve beside a clearer orientation in the local Neogene lithostratigraphy also for the primary orientation in local geotechnical parameters values of the subsoils. An analogous study will be elaborated in the further continuation on an area of the wider city centre.

Key words: Danube Basin, Bratislava, Neogene, Volkovce Fm., Beladice Fm., geotechnical characteristics of subsoils

Manuskript doručený: 2016-03-01

Manuskript revidovaný: 2016-05-17