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Foundation of traffic embankments on clayey landfills of SHR
Mužík, Vlastimil ; Boháč, Jan (advisor) ; Kudrna, Zdeněk (referee)
Title Foundation of traffic embankments on clayey landfills of SHR Abstract This Bachelor thesis was worked out for Faculty of Science of Charles University in Prague led by Ing. J. Boháč. The thesis deals with motorway embankment over the landfill A. Zápotocký, which is part of motorway strech D8-0807/I. The thesis compiles research results, monitoring of trial embankments and monitoring performed by the own construction motorway embakment. Based on these data is determined the creep portion of the total settlement.
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Properties of alluvial sediments at Albertov, Prague
Chvílová, Martina ; Boháč, Jan (advisor) ; Lešner, Jeroným (referee)
Bachelor thesis deals with the sediments of river terraces in Prague, Albertov. On these sediments from the deep drill hole J6 in campus Albertov area I made eight grain measurements, processed grain curves and normatively classified terrace soils with classes S1, S2, S3 and F3, F4. They are sandy soils partly containing fine gravel or fine fraction admixture. I also performed the grain analysis on soils 1,5m deep in near morphological distance from the drill hole on which bases I searched for analogy between sediments on campus Albertov building site. They are recent soils of local and foreign digged material. In documented terrace material with S2 character was observed that with content of fine- grained fraction under ca. 5% the increase of the proportion of fine-grained admixture elevates the angle of sands natural slope.
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Variability of mechanical properties of coarse-grained soils
Zmek, Petr ; Mašín, David (advisor) ; Boháč, Jan (referee)
In a domain of geotechnical engineering, numerical models are used in different situations with success. As an example, numerical models are used in slope stability analyses in different geological environments. To calibrate numerical model for specific geological conditions many samples have to be taken and analysed. One of the parameters of constitutive models is an angle of repose. The angle of repose was measured by four different methods. Subsequent statistical analyses proved a difference between the chosen methods.
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Mechanical behaviour of variably saturated clay fills
Kostkanová, Vladislava ; Boháč, Jan (advisor) ; Kurka, Jan (referee) ; Vaníček, Ivan (referee)
Mechanical behaviour of variably saturated clay fills VLADISLAVA KOSTKANOVÁ Ph.D. Thesis - English Abstract The excavated overburden from open-cast coal mines is end-dumped in fills. Clay type soil prevails among the filled soils in North-western Bohemia. As a consequence of the character and state of the soil, together with the mining and dumping technology, a typical lumpy structure of the clay fill is formed. The filled lumps range in size and vary in mechanical properties, but stiff to solid lumps up to 0.5 m in size are prevalent. Large and open macrovoids between the single lumps are a characteristic feature of the clay fills. Clay fills exhibit a double porosity structure, consisting of intergranular porosity between the lumps and intragranular porosity inside them. The total porosity of the freshly filled soils can reach 70%. This type of clay fill structure is metastable. This thesis focuses on the problematic behaviour of clay fill soils due to their metastable structure and their partly saturated state. Long-term monitoring of matric suction at depths up to 2 metres in two reclaimed clay fills revealed two different trends. Seasonally-dependent suction oscillations were recorded in the moderate slope of the clay fill in the Bílina mine, while no suction pointing to fully saturated conditions was...
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Foundation of traffic embankments on clayey landfills of SHR
Mužík, Vlastimil ; Boháč, Jan (advisor) ; Rozsypal, Alexandr (referee)
4 Abstract This Bachelor thesis was worked out for Faculty of Science of Charles University in Prague supervised by J. Boháč. The thesis deals with motorway embankment over the A. Zápotocký landfill, which is a part of motorway strech D8-0807/I. The thesis compiles the monitoring data of the trial embankments and monitoring of final motorway embakment. Based on these data is the creep portion of the total settlement estimated.
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Suction in undisturbed samples of Brno Clay determined by filter paper method
Mohyla, Tomáš ; Boháč, Jan (advisor) ; Malát, Richard (referee)
Negative pore pressure (suction) in soils can be measured by various methods. Probably the most precise way is using the 'Imperial College suction probe', which is briefly described, was however not available. A simple alternative is represented by the filter paper method. It was used to determine the suction in the undisturbed samples of the overconsolidated Miocene clay from the town of Brno (Brno Tegel). However the capillary suctions determined by the filter paper were unrealistically high, and could not be used in estimating the in-situ horizontal stresses (at rest coefficient K0) in the Tegel. The reasons for the failure are discussed and possible future steps are suggested.
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Horizontal stress in Brno Clay determined by oedometer test
Krupička, Martin ; Boháč, Jan (advisor) ; Mašín, David (referee)
This Thesis deals with the determination of horizontal effective stress in-situ the clay massif in the city of Brno. To determine the value of the horizontal in-situ stress was at first established value of the coefficient of earth pressure at rest K0, which captures stress conditions in the massif and which is a main part of this Thesis. To determine the value of K0 was used the method of the ratio of the horizontal to vertical preconsolidation pressure. Pseudo-preconsolidation pressure used to calculate K0 was determined by using standard oedometer compression tests of oriented undisturbed samples. Research part of the Thesis deals with the issues of evolution of K0 during secondary compression and results of previous published data. The results obtained from own experiments are discussed and compared with the results of previous published data.
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Modelling of soil asymptotic behaviour using discrete element method
Jerman, Jan ; Mašín, David (advisor) ; Boháč, Jan (referee)
Aim of this study is to characterize asymptotic states of particulate materials, including states in extension. Asymptotic states are defined as states reached after a sufficiently long stretching with a constant direction of the strain rate. They are attractors in the behaviour of granular material and they are reached independetly of the initial state. Discerete element method is used in the simulations, where the influence of strain rate direction on the final state is studied. Results for strain rate direction higher than 0 obtained by Mašín (2012a) are then compared with results for strain rate direction lower than 0. These sets of results coincide qualitatevely.
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Foundations on clay fills of North Bohemian coal mines
Novotný, Václav ; Boháč, Jan (advisor) ; Kudrna, Zdeněk (referee)
The work is focused on the issue of using landfills as building sites and the experiences so far gathered with founding buildings on them. It describes in brief the geology of the overburdens of coal seams and the processes by which the spoils are treated during mining and deposition of landfills. The work focuses on the properties of the spoils and specific attributes of the geological engineering survey of landfills. The goal of the work is the accumulation and evaluation of available experience with building on landfills of north Bohemian coal mines. Interpretation of the available information can lead to an increase of interest of investors in these localities and a decrease in building costs on landfills. A background research of literature on the topic that is a part of this work can be used as grounds for the optimization of building on clay landfills.
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Critical state strength of Brno Clay
Fencl, Michal ; Boháč, Jan (advisor) ; Najser, Jan (referee)
The Thesis deals with the critical state strength of Brno Clay. The critical state strength is an important input parameter in many geotechnical analyses. Further it is used in determining the at- rest coefficient K0 of normally consolidated clays using the Jáky formula. The Thesis first briefly describes the concept of strength for soils and the K0. The critical state strength of the particular soil is then determined by using triaxial conventional and frictionless specimens, and two types laboratory direct shear measurements, namely in the translational and ring shear boxes. The obtained results are discussed and compared with previous published data.
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