Sebastian Olesiak and Joanna Hydzik-Wiśniewska
The paper evaluates the effectiveness of reinforcing a damaged earth structure with making counterfort drains in its slope. The system of counterfort drains changed the soil properties significantly over a long-term use. The evaluation was based on many years of field and laboratory tests and stability analysis. The field tests concerned the observation of N WST probing resistance change, and the laboratory tests concerned the change in soil consistency and water content. The paper presents the results of tests that were conducted over 13 years.
The article attempts to develop a preliminary practical framework for urban criteria in terms of the population, economy and spatial location of the smallest towns in Poland. Despite being of little significance, the fact that they lie near the border between being rural settlements and towns makes them an interesting subject for research and more detailed analysis. The current phenomenon of urban status being obtained by ever-smaller settlements is causing conceptual disorder. Therefore, the article may serve as an early contribution to a discussion about the need to define and unify urban criteria on a national scale. The qualitative and descriptive guidelines contained in official acts are insufficient and too general, which is why quantitative methods were used in the present research. Despite the limited data available, research on the topic of urbanity has proven the imperfection of the Polish administrative system and confirmed the premise that town status may be conferred inappropriately in numerous cases.
Joanna Maria Badach, Anna Stasiak and Andrzej Baranowski
In civil societies, urban movements are one of the tools in the process of spatial governance. In Poland, urban activism is beginning to develop together with a budding participation in public life. Therefore, there is a need to assess the scope and effects of the urban movements’ actions. The aim of the study was to determine and evaluate their impact on the spatial development in three Polish cities - Poznań, Gdańsk and Gdynia, especially in regard to the procedures in local urban planning and the process of participation. On the basis of the data collected during research and community interviews conducted in these cities, the following factors were analysed: the background and current profile of urban movements, the extent, regularity and effectiveness of their actions, the planning and spatial development initiatives undertaken, their cooperation with the local authorities and their contribution to the enhancement of participatory mechanisms.
In the present manuscript, unsteady magnetohydrodynamic (MHD) flow over a moving porous semi-infinite vertical plate with time-dependent suction has been studied in the presence of chemical reaction and radiation parameters. Time-dependent partial differential equations in the dimensionless form are solved numerically through mathematical modelling in COMSOL Multiphysics. The results are obtained for velocity, temperature and concentration profiles at different times. Steady state results are also presented for different values of physical parameters. The parameters involved in the problem are useful to change the characteristics of velocity, heat transfer and concentration profiles. The numerical solution of partial differential equations involved in the problem is obtained without sacrificing the relevant physical phenomena.
There are many classifications of atmospheric circulation types. In Poland, the most important one, used by Polish weather services, is the classification of circulation types developed by Lityński. This paper proposes four modifications to the currently used algorithm for determining atmospheric circulation types. The proposed algorithms have been compared and it has been shown which one produces a catalogue of circulation types in which the division of the distribution of the values of the three indices (the zonal index Ws, meridional index Wp and cyclonicity index Cp) into three classes is the closest to being equally likely. In 1986-2015, the classification scheme that deemed to be the best, differed in above 19% of cases from the currently used classification.
Agnieszka Joanna Sosnowska
Plant succession is quite a common phenomenon in Poland, especially in agricultural landscapes. At the turn of the 21st century there was a significant increase in the area of fallow lands. That increased the area occupied by ruderal and segetal vegetation. The development of vegetation on post-agricultural lands transforms soils. The aim of this paper is to determine changes in vegetation and soil properties that occur as a result of secondary succession on post-agricultural lands in loess landscapes
Andrzej Batog and Elżbieta Stilger-Szydło
Road embankments, especially their slopes’ surfaces, must fulfil all the requirements concerning the exploitation criteria after the completion of construction works. This is very important while constructing or modernizing the embankments, based on the substrate including low-strength soils as well as in simple ground conditions (most convenient). The last dozen or so years of intensive construction of transport infrastructure have shown how big is the problem of ensuring the required volumes of qualified soil material for the construction of road embankments or the modernization of railway embankments. The depleting deposits of natural and easily accessible soils for the construction of embankments result in the need to use anthropogenic soils, for example, in the form of aggregates from the recycling of construction waste and other locally available waste materials, usually in the form of slag and ashes from the combined heat and power plants. In such cases, there’s a need to treat transportation earth structures individually in the scope of designing and quality control, because there are no applicable standard provisions in this scope.
This work indicates some of these important contemporary problems of transport engineering, occurring in newly built and modernized road objects, such as the stability of road embankments based on a low-strength substrate, use of anthropogenic soils and materials originating from the recycling of concrete surfaces for the construction of road embankments.
Szczepan Grosel, Michał Pachnicz, Adrian Różański, Maciej Sobótka and Damian Stefaniuk
In the paper, the influence of different types of bedding and backfill soil surrounding underground sewage duct on its deformation was analysed. Impact of increased soil lateral pressure was examined by considering the construction of an embankment nearby the underground pipeline. Numerical computations of three different variants of bedding and backfill soil surrounding the pipe were carried out. Displacements and deformation of the pipe were calculated using the finite element method with adoption of elastic-perfectly plastic constitutive model of soil. Subsequent stages of the construction were taken into account. Shear strength reduction method was applied to evaluate the factor of safety of the entire system. Finally, the results and conclusions were depicted.
Nabil Manchar, Chaouki Benabbas, Riheb Hadji, Foued Bouaicha and Florina Grecu
The purpose of the present study was to compare the prediction performances of three statistical methods, namely, information value (IV), weight of evidence (WoE) and frequency ratio (FR), for landslide susceptibility mapping (LSM) at the east of Constantine region. A detailed landslide inventory of the study area with a total of 81 landslide locations was compiled from aerial photographs, satellite images and field surveys. This landslide inventory was randomly split into a testing dataset (70%) for training the models, and the remaining (30%) was used for validation purpose. Nine landslide-related factors such as slope gradient, slope aspect, elevation, distance to streams, lithology, distance to lineaments, precipitation, Normalized Difference Vegetation Index (NDVI) and stream density were used in the landslide susceptibility analyses. The inventory was adopted to analyse the spatial relationship between these landslide factors and landslide occurrences. Based on IV, WoE and FR approaches, three landslide susceptibility zonation maps were categorized, namely, “very high, high, moderate, low, and very low”. The results were compared and validated by computing area under Road the receiver operating characteristic (ROC) curve (AUC). From the statistics, it is noted that prediction scores of the FR, IV and WoE models are relatively similar with 73.32%, 73.95% and 79.07%, respectively. However, the map, obtained using the WoE technique, was experienced to be more suitable for the study area. Based on the results, the produced LSM can serve as a reference for planning and decision-making regarding the general use of the land.