GEOMECHANICKÉ VLASTNOSTI NEOGENNÍCH JÍLŮ NA ÚZEMÍ MĚSTA BRNA
Neogene clays in Brno area are formations belonging to the Carpathian Foredeep Basin. They form common foundation soil in this strongly urbanized area. Due to their specific mechanical characteristics and a large spreaded area in Brno a detailed study of the geomechanical properties of Neogene clays has practical importance for engineering geology and geotechnics. There are compared analyzed data of physical and mechanical properties from 81 engineering-geological reports at the Brno agglomeration (452 samples of Neogene clays from 180 bores). There are presented the anomalous, distant values, arithmetic average and mode of the Neogene clays. On the basis of assumed data from various geological-engineering reports are defined typical characteristics of these soils. Neogene clays are fine-grained cohesive soils. In terms of ČSN EN ISO 14688-1, 14688-2 and UCSC classification these are classified mainly as clay or silt with high, very high or extremely high plasticity. It is usually with high plasticity index, stiff and very stiff consistence and with medium and high undrained shear strength. Low values of cohesion could be related to soil damaged by landslide movements. Due to its unfavourable properties, Neogene clays refer to partly suitable environment for shallow strip-foundations mainly due to the possibilities of volume changes in the subground. For all projection of foundations, there should be paid special attention to good engineering-geological investigation at real site.