Verification of compressibility and consolidation parameters of varved clays from Radzymin (Central Poland) based on direct observations of settlements of road embankment

Abstract

Formation of varved clays is characterized by specific compressibility and consolidation features, which are difficult to assess. The construction of an expressway through the area of varved, glacilimnic sediments (Vistula glacial period) required careful analysis of the soil reaction to the increasing load caused by growing embankment. The settlement analyses conducted in relation to the schedule of load increase during construction allowed to verify the deformability assessment of the compressible clays. In order to quantify the compressibility and consolidation parameters of clays, an iterative calculation model was created. The method of the “inverse solution” was used to define optimized values of deformability parameters. The observed delayed reaction of the soil to applied load allowed to assess the nature of consolidation. Comparison of the parameters obtained from the model with the results of laboratory and field tests allowed to evaluate drainage characteristics during consolidation of varved clays as well as to introduce correlation coefficients for interpreting compressibility parameters on the basis of CPT tests.

Rivers Try Harder. Reversed “Differential Erosion” as Geological Control of Flood in the Large Fluvial Systems in Poland

“…As the bedrock, we regard not only the Mesozoic solid rocks (limestones, sandstones) but also glacial tills and lacustrine (or ice-dammed lake) cohesive sediments (mostly clays) deposited during the Cenozoic, but before the Holocene. These sediments are resistant to erosion (in comparison to the Holocene alluvial sand) due to their cohesive strength [38,39] and due to strength received from glacial pressure-preconsolidation [40][41][42]. The lines of the upper limit of the non-alluvial protrusion were marked by a color that refers to the age according to the chronostratigraphic chart [43].…”