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Geotechnické řešení protipovodňových opatření
Krajčovič, Ján ; Chalmovský, Juraj (referee) ; Račanský, Václav (advisor)
Main target of work is problematic of flood protection systems and possibilities of improvement of them by methods of geotechnical solutions. Parts of work are overview of basic flood protection systems and resume of normative requirements for design of levee against flood. Practical part of work is composed from complex overview of geotechnics methods used for levee improvement. Work is ended by examples from practice.
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Load-displacement behavior of ductile micropiles in cohesive soils
Stoklasová, Andrea ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
This thesis is focused on creation of mobilization curves, based on data, obtained from standard and detailed monitoring of the load test. The load test was performed on the 9 meters long ductile micropile. The first part of the thesis explains the methods and principles, which was used to construct the mobilization curves. Next there is description of the technologies of ductile micropiles and the load test. In the next part of the thesis is generally explained process, which was applied to the evaluated data. For evaluation was used spreadsheet Microsoft Excel and programming language Matlab, with Kernel Smoothing extension. In the last chapter of the thesis there are interpreted the load transfer function together with skin friction and micropile displacement.
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Stress analysis of jet grouted shafts
Tarbajová, Mária ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
The subject of the diploma thesis is the stress analysis of the circular and elliptical shaft from material jet grouting. A new advanced constitutive Shotcrete model will be applied on the material jet grouting. In the thesis, the shaft tensile strength factor and the size of the ground pressures will be primarily examined. The practical part of the diploma thesis is completed by the comparison of the analytical and numerical calculation of the normal force of the circular and elliptical shafts.
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Numerical analysis of stability of retaining structure in cohesive soils
Fejfarová, Aneta ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
The bachelor thesis deals with numerical modeling of excavation using finite element method in the Plaxis 2D software. Triple-anchored retaining structure is founded in a less permeable cohesive soils. There are described loss of stability, types of the calculation and material model (Hardenig soil model used in the mathematical model) in the theoretical section of this bachelor thesis. Mathematical model of the excavation was described in the practical section of this thesis, specifically first limit state. Part of the thesis is an evaluation of the degree of stability over time, pore pressures and critical shear surfaces.
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Ground retaining structure for cut & cover metro station in Qatar
Kočičková, Veronika ; Račanský, Václav (referee) ; Uhrin, Michal (advisor)
The aim of this thesis is to assess the geological conditions and durability of the cut and cover metro station in Qatar. Furthermore, the thesis deals with the construction sequence and structural checks of selected elements of the structure. The geological conditions were evaluated on the basis of an extensive geotechnical investigation that was conducted at the construction site. This research also gave necessary information for durability design. After the assessment of the ground conditions in the thesis, it was possible to choose suitable retaining walls and lateral support system and continue with a plan of construction sequence. A diaphragm wall and mezzanine level prop were chosen for the structural check. In case of the wall, the main load was caused by bending moments of a big significance, therefore the wall was designed to the envelope of these moments obtained from software Plaxis. Furthermore, it was necessary to consider the interaction of bending moments and normal forces for the design of the prop. For both elements, reinforcement of bigger diameters was designed.
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Evaluation of loading test of jet-grouted piles
Čechová, Simona ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
The master thesis consists of a theoretical part and a practical part. In the theoretical part jet-grouting technology is described briefly. Mechanical properties of jet-grouted piles were characterized. Various estimation methods of ultimate pile bearing capacity are described in this thesis – analytical calculation of ultimate bearing capacity for bored piles and estimation of ultimate pile bearing capacity by analysis of load-displacement curve defined by CHIN (1970; 1972). Load transfer method for piles and hyperbolic load-transfer curve are introduced. As a part of the load-trasfer method analysis, a method of estimating ultimate pile shaft friction called beta method is defined. In the practical part were evaluated several static load tests of jet-grouted piles and were constructed their load-displacemnt curves. Then reverse analysis of the results from static load tests was performed using load-transfer method. Then ultimate pile bearing capacity was estimated using analytical calculation of pile bearing capacity for bored piles and using analysis of load-displacement curve with method by CHIN (1970; 1972). By evaluation of load transfer method and beta method ultimate shaft resistence for each pile was estimated. Results and load-displacement curves were compared.
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Determination of load-transfer functions for bored piles
Čechová, Simona ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
The thesis is consisted of theoretical and practical part. In theoretical part was described nowadays commonly used method for analysis of single axially loaded replacement piles defined by Masopust (1994). There was also explained principle of load transfer method and was done analysis of mobilization curves, which are applied abroad, and finally were defined essential entry parameters for construction of selected load transfer curves. In practical part method by Masopust (1994) was transformed, limit shear stresses and tip resistances were calculated and values of deformation parameters for constructing cubic root curve and hyperbolic load transfer curve were deterined. In the last step both types of load transfer curves were constructed for shaft and pile tip of a replacement pile in different depths in fine-grained soil and in coarse-grained soil.
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Evaluation of load tests of permanent ground anchors instrumented with optical fibres
Chylík, Zdeněk ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
The thesis focuses on evaluation of load tests of permanent ground anchors instrumented with optical fibres. The thesis is divided into six parts. The first patr introduces topic of the thesis and work procedure. The second part contains all the information about the tested ground anchors, the building site, the loading scheme and methods of measuring. In the third part is evaluation of the apparent tendon free lenght and comparison of measurement methods. Fourth part includes evaluation of sheat friction in the free length. The fifth part describes the behaviour of the part, where free length changes to bond length. The sixth section presents an overall results with suggestions for possible continuation.
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Evaluation of selected load tests of ductile piles instrumented with distributed fibre optic sensors
Genzer, Christian ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
Despite the fact that the use of driven ductile piles is not as widespread in the Czech Republic as in surrounding countries, this method provides a fast and reliable solution for foundation structures. To verify and optimise the design, in-situ load tests are often carried out on a realistic scale. As a standard, string or resistance strain gauges are used to measure the resulting deformations. Although their use is cheap and relatively simple, the measured results do not provide a complex view of the behaviour of the structure over its entire length and with sufficient accuracy. Therefore, in recent years, the application of fiber optic-based measurement systems has been increasing. The goal of this bachelor thesis was to evaluate several load tests of driven ductile piles fitted with fibre optic sensor systems, considering a number of factors that negatively affect the measurement results. Examples of these include pile bending, measuring oscillations due to the technology of execution and the method of measurement, or the development of tension cracks in the grouting. For each load test, the site geology and test pile parameters were specified first. Afterwards, the technology of the performed load test was described and the results of standard monitoring were presented. Based on the measuring from distributed fibre optic sensors, the relative strain and axial force curves were constructed, from which the ultimate skin friction values were determined. These values were correlated with the driving times in each pile section and based on this relation the K_SHAFT coefficients were set. At the end of the thesis is presented a summary of the collected data and their comparison between each other.
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Evaluation of loading test of jet-grouted piles
Čechová, Simona ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
The master thesis consists of a theoretical part and a practical part. In the theoretical part jet-grouting technology is described briefly. Mechanical properties of jet-grouted piles were characterized. Various estimation methods of ultimate pile bearing capacity are described in this thesis – analytical calculation of ultimate bearing capacity for bored piles and estimation of ultimate pile bearing capacity by analysis of load-displacement curve defined by CHIN (1970; 1972). Load transfer method for piles and hyperbolic load-transfer curve are introduced. As a part of the load-trasfer method analysis, a method of estimating ultimate pile shaft friction called beta method is defined. In the practical part were evaluated several static load tests of jet-grouted piles and were constructed their load-displacemnt curves. Then reverse analysis of the results from static load tests was performed using load-transfer method. Then ultimate pile bearing capacity was estimated using analytical calculation of pile bearing capacity for bored piles and using analysis of load-displacement curve with method by CHIN (1970; 1972). By evaluation of load transfer method and beta method ultimate shaft resistence for each pile was estimated. Results and load-displacement curves were compared.
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