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Impacts on collapse behaviour of soils
Herbstová, Vladislava ; Herle, I.
Phenomenon of collapsible soils is a broadly investigated problem of the soil behaviour. A review of the collapse potential of different soils – sand and loess is presented. Various dry unit weights and degrees of saturation are interpreted in terms of the collapse index dependent on applied vertical stress during sample flooding.
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Advantages and disadvatages of a hypoplastic model when used in modelling of deep excavations
Jelenová, Věra ; Mašín, David (advisor) ; Najser, Jan (referee)
In building construction, it is important to know in advance how the ground will behave in an area around an excavation. To do this we use numerical models, which predict the behavior of soils. There are many numerical models that more or less precisely predict the behavior of soils. In this thesis I will focus mainly on the hypoplastic model. It predicts the behaviour of soils well. The model has also several disadvantages, especially while predicting stress paths at small strain. I will then also describe an improved hypoplastic model, which clarifies the predictions of the soils behaviour. This thesis is created mainly as a core for a diploma thesis, which should focus on modeling of the soils behaviour, the improved hypoplastic model and excavation near the Bodam lake. This excavation was already a subjekt of a diploma thesis (Becker, 2009), but there only the original hypoplastic model was used. This thesis focuses on the description of some aspects of the mechanical soils behavior. The describtion of the original and the improved hypoplastic model and their parameters follows. In the other part of this thesis we describe the selected buiding projects of excavations in fine-grained soils.
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Influence of Partial Material Factors According to EUROCODE 7-1 - Shallow FOundations
Koudelka, Petr
A formerly presented similarity solution of bearing capacity of shallow foundations (Koudelka 2006) improved according to EC 7-1 is used in the paper. The solution forms the basis of a comparative analysis enabling a simpler numerical analysis. The scale of the analysis should be sufficiently wide to cover the usual soils. In the frame work of the analysis, the EC7-1 and ČSN 73 1001 design results are compared with the tables of design bearing capacities of ČSN 73 1001. The result evaluation leads to a simple non-conventional conclusion.
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Status of soil organic carbon content of selected reclaimed sites in the Podkrušnohorská dump.
KOBESOVÁ, Martina
The main aim of this thesis was to assess the status of soil organic carbon in newly shaped soils called Velká podkrušnohorská dump in the Sokolov district and evaluate the information in relation to the physic-chemical properties of soils. Another objective was to determine the relationship between the stable and labile fractions of soil organic carbon. The amount of soil carbon (stable fraction) was measured in the solid soil samples and there was the analysis of basic physic-chemical parameters of the soil performed. The highest concentration of soil carbon was measured in the stand alders and larch. The amount of soil carbon (labile fraction) was measured in the water extract. The highest values were measured in the stand silver birch and alders. Based on this data the quotient of the labile fraction from the stable fraction was determined and the correlation of the labile and stable fractions was made. It was found out that the higher quality soils are located at the leafy trees, but it leads to leaching of organic carbon. The bulk density and coarse-grained soil fraction was determined from the physical properties and these data were used to calculate the stock of soil organic carbon. The highest value was measured in deciduous forests with small-leaved linden, in coniferous forests with larch. The stocks of soil organic carbon were converted into codes by land cover categories and the thematic map was created. It was found out that the leafy trees are much more appropriate for forest restoration, because they are characterized by the rapid initial growth, easily degradable plant litter and stable form humus. Deciduous forests are also characterized by more developed soil substrate, which is however unstable.
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Inovace klasifikace a zkoušení podložních zemin pro realizaci lesních odvozních cest
Tvrdý, Daniel
Basic presumption of good functionality of forest roads is not only high quality of laminars in flexible pavement, but also right distribution of elasticity modules in soil plain and it's protection against degradation during the process of building. Materials used for TA ČR project, which were isolated from forest roads subsoil, were analyzed in soil mechanics laboratory of Geostar s.r.o. company for the purposes of diploma thesis. Basic laboratory tests were carried out in order to classify soils. Sub-component is to propose a simplified classification of soils for the implementation of forest haul routes. In this work are validated according to the static load tests ( SZZ ) and dynamic light boards ( LDD ) . The thesis includes evaluation of the quality of existing forest roads for faults and failure on forest roads classes 1L and 2L with different surfaces and ground covers .
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Analysis of soils
Šašek, Petr ; Viani, Alberto ; Ševčík, Radek ; Mácová, Petra ; Machová, Dita
High concentrations of solid particles in the air may cause health problems. Sources of such particles can be natural processes, as well as human activity (e.g. coal mining, etc). Another source of contamination is the so-called secondary dustiness, which arises from vortex of already settled solids and dispersion into the atmosphere. Secondary dustiness formation is mainly affected by the surface moisture. The increase of humidity leads to agglomeration of the particles, resulting to their falling on ground, thus inhibiting their distribution in the atmosphere. The aim of the study was to analyse the soil dust particles collected on the filters of impactor, with respect to particle size and composition.
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Soil microscopic fungi in two different mine spoils in the Lusatian mining district
Nováková, Alena
Soil microscopic fungi (including keratinophilic, cellulolytic and thermophilous fungi) were studied in two representative mine spoils (Terciary, marine brackish carboniferous and pyritic sands and Quaternary fluvioglacial sands) in the Lusitanian mining district. Spoils were amended with lime, ash, sewage sludge, mineral fertilisation and compost and also without any treatment. Experimental plots were planted with pine seedlings (Pinus sylvestris L.), control plots were not planted (spontaneous plant succession). Differences in species diversity were estimated among different treatments and also between studied mine spoils, significant differences were recorded in quantitative estimations (CFU counts, fungal biomass).
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Processes of soil carbon sequestration on reclaimed areas of the Podkrušnohorská dump.
KOBESOVÁ, Martina
The main objective of this thesis was based on samples from the localities to determine the processes of soil carbon sequestration in reclaimed areas of the Velké podkrušnohorské dump and to evaluate the results in relation to physical and chemical properties of soil. The amount of soil carbon was measured from the collected samples and the soil was analyzed of basic physical and chemical soil parameters. The largest concentration of soil carbon was measured in the alder stands.
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Monitoring the impact of simulated rainfall on soil with flushing water by EIS method
Slezák, Jakub ; Novotná, Jitka (referee) ; Pařílková, Jana (advisor)
The diploma thesis with name “Monitoring the Impact of Simulated Rainfall on Soil with Flushing Water by EIS Method” deals with the problems of soil degradation due to salinization and sodification in consequence of infiltration of flushing waters from roads during winter maintenance. This experiment was realized in laboratories of the Institute of water structures of the Faculty of Civil engineering at Brno University of Technology and researched the influence of simulated rainfall on degraded soil by method of electrical impedance spectrometry (EIS). The thesis follows the solution of projects in international EUREKA program.
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