Reliability of equilibrium state evaluation about settlement slopes in the context of natural and human-made hazards is a complex issue. The geological structure of the vicinity of the upland slope in the urban environment of Warsaw is characterised by a significant spatial diversification of the layers. This is especially due to the glacitectonics in the Mio-Pliocene clays, which are located shallowly under the sandy tills’ formations. With substantial variability in the clay roof surface, point recognition by drilling is often insufficient. The use of electrical resistivity imaging (ERI) in the quasi-3D variant provides accurate images of the real ground conditions, which is crucial in optimal geotechnical design. In forecasting the behaviour of the slope, it is necessary to quantify the impact of spatially differentiated systems of disturbed layers on changes in the safety factor (SF), which corresponds to the observed landslide activity of the Warsaw Slope. This study concerns numerous calculation model analyses of the optional clay position in the context of slope stability conditions. A wide range of soil properties variability was taken into account, resulting from both lithogenesis and subsequent processes disintegrating the original soil structure. Regarding the geological conditions of the slip surface, the use of classical computational methods and numerical modelling (FEM) was considered for comparative purposes. The results indicated that local changes in equilibrium conditions were affected by the different morphology of the clay roof surface of the slope and the alternation in strength characteristics on the slip surfaces. The findings of the study contribute to sustainable spatial planning of near-slope regions.

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.

This article presents the results of petrophysical analyses of limestones and sandstones used for the construction of the wall structures of a Roman rural settlement located in Podšilo Bay on Rab Island (Croatia). An on-site analysis of the walls indicated the use of different lithotypes, which is an uncommon case in the area. So far, no petrophysical properties of the applied materials have been tested, and their provenance has not been specified. The aim of this research was to determine their usability as construction materials in an attempt to determine the possible reasons behind the usage of multiple lithotypes and their suitability as building materials. The following procedure was used to address these issues: (1) determination of the petrographic characteristics of the rocks, (2) performance of tests to characterise the mechanical properties in a complex stress state of uniaxial tension followed by uniaxial and triaxial compression, and, finally, (3) determination of the internal structure of the rocks using methods based on X-ray imaging. Multi-proxy characteristics of the materials including numerous observations and methods were performed: optical microscopy used to characterise rock petrography and mineralogy, scanning electron microscopy (SEM) coupled with EDS, as well as grinding tests; furthermore, mechanical properties were determined on cylindrical samples in accordance with European standards. X-ray microtomography using the XμCT method enabled microscopic observations and determination of the orientation of discontinuities and the rock structure. The performed analyses allowed us to distinguish three lithological types of sandstone and two types of limestone among the examined stone blocks. Stone blocks of fine- and medium-grained sandstone with carbonate binders, as well as sparitic limestone and mudstone with calcite veins, were used to build the studied structures. The analysed blocks showed traces of partial edge processing. Despite the defects in the material structure identified using XμCT, all the types of rock were characterised by high or very high strength. High values of longitudinal wave velocity confirmed the good quality of the material. These results contribute to a better understanding of the construction process and the related technological choices, and they provide the first dataset which can be used for the reconstruction of the building’s original appearance in the future.

The paper presents the results of experimental laboratory investigation of cohesive soils from the Warsaw area, polluted with diesel fuel. The study revealed adverse changes in key physical parameters, sorption capacity and mechanical properties. The results were analysed in relation to pollution degree as well as structural modifications. The obtained findings were further used in numerical analyses to evaluate bearing capacity, foundation settlement, and slope stability, as well as to assess the overall behaviour of contaminated soils serving as building foundations.