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Small strain stiffness of soils and methods of its measurement
Havlíček, Jaroslav ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
This thesis consists of theoretical and practical part. Firstly, the soil behaviour at small-strain range and its physical nature are described. Subsequently, the individual soil parameters affecting the value of small-strain shear modulus and the shape of the stiffness reduction curve with increasing shear strain are described. The individual methods of measuring the small-strain stiffness in the laboratory and in-situ with a more detailed explanation of the evaluation of measurements using bender elements are given in the last chapter of the theoretical part. In the practical part, a device for measuring small-strain stiffness using bender elements was put into operation. The used laboratory equipment is described first and then the parameters of tested soil are given. The main chapter is measurement and evaluation of the impact of software and hardware settings and the influence of effective stress of soil on the small-strain shear modulus that is compared with predictions of empirical expressions from the literature.
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Verify stability of ground anchor system
Krško, Matúš ; Doněk,, Michal (referee) ; Miča, Lumír (advisor)
Bachelor´s thesis is focused on stability of anchored system. Theoretical part deals with various types of anchored walls, their construction technology and failure states that can occur. Methods for assessment of internal stability are presented in the next step. They are applied to a model anchored wall in a calculation part. Obtained results are evaluated at the end the thesis.
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Numerical analysis of culvert
Krtek, Jiří ; Doněk, Michal (referee) ; Miča, Lumír (advisor)
The topic of this Thesis is a study of the behavior of flexible metal large-span culverts during the construction and the operation. The aim is to analyze the behavior of the structure as a result of an unequally dropping support and a position of the load to the construction in relation to the soil cover height above the top of the steel construction. The Thesis is theoretical and based on the numerical parametric study.
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Design of retaning structure in the Brno- sever district
Koporec, Vladimír ; Koudela, Pavel (referee) ; Miča, Lumír (advisor)
The bachelor's thesis deals with the design of the sheet pile construction of the construction pit of the underground car park of a multifunctional house in Brno and its impact on the adjacent tunnel. The design and assessment of the sheet pile structure is developed on the basis of the results obtained in the GEO5 program. For a more detailed analysis of the impact of the proposed sheet pile structure on the adjacent tunnel, a numerical analysis is performed in the PLAXIS 2D program. As part of this analysis, a study of the influence of the material model (Mohr-Columb, Hardening soil and Hardening soil small) on the change of deformations and internal forces in the tunnel is made. The results of the work show the interaction between the proposed structure and the tunnel.
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Alternative methods for foundation the circular tank in fine-grained soils
Vodáček, Ondřej ; Zdražil,, Karel (referee) ; Miča, Lumír (advisor)
Foundations on unbearable and yielding subsoil require such actions as to achieve both desired bearing capacity and limited settlement. Issue is presented at foundation the circular tank in saturated fine-grained soils, circular tank in Klobouky u Brna in particular. Comparison analysis is performed for alternative methods (shallow foundation, vibro stone columns, deep soil mixing, pile foundation). Differential and total settlement, time-depending analysis and baseplate stress state (bending moment, shear force) are assessed for each alternative. Pile foundation provides the best results regarding total and differential settlement, but baseplate is also under high puncture shear stress. Vibro stone columns seem suitable due to time-depending analysis of settlement, on the other hand settlement reductions are not just as good. Deep soil mixing provides satisfactory alternative for both pile foundation and vibro stone columns. Under such circumstances shallow foundation is not suitable.
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Behavior analysis of a ground anchor fixed length in fine grained soils
Chalmovský, Juraj ; Turček,, Peter (referee) ; Hrubešová,, Eva (referee) ; Miča, Lumír (advisor)
Ground anchors represent an important structural element in the area of ground engineering. Despite an extensive usage of these elements, their design is usually performed using simple empirical and semi-empirical methods. An application of these procedures brings to the design a number of simplifying assumptions. The goal of the dissertation is to refine the computational design of ground anchors, analysis and quantification of selected factors significantly affecting their load displacement behavior. Firstly, the finite element method is applied. Two novel constitutive models are used: Multilaminate Constitutive Model for Stiff Soils (Schädlich, 2012) involving post peak shear softening of overconsolidated cohesive soils and Shotcrete Model (Schädlich, 2014) involving tension softening after tensile strength is reached. First constitutive model was used in order to simulate progressive decrease of skin friction along the anchor fixed length. Second constitutive model was applied for the grout material. In the next step, experimental program including several anchor load tests was carried out. The goal of the experimental program was to confirm conclusions from numerical studies and to obtain relevant data for further back – analysis. A newly developed application, in which all the findings from numerical computations and experimental measurements are incorporated, is described afterwards. The application is based on the use of so-called load-transfer functions. The program verification was conducted through series of back analysis of investigation anchor load tests realized on four different construction sites in two different types of fine-grained soils. The verification of the application is followed by series of parametric studies in which an influence of input parameters values is analyzed. Dissertation is concluded by the summarization of the most important findings.
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Time depending analysis of subsoil reinforced by stone columns
Vykoukal, Libor ; Doněk,, Michal (referee) ; Miča, Lumír (advisor)
The thesis focuses on the time analysis of the subsoil which is reinforced with stone columns and without them. The subsoil is made of saturated clays. Main purpose is to introduce the improvement into the numerical models. For the purpose of the diploma thesis the software Plaxis has been chosen, which is normally used for geotechnical tasks. The influence of the stone columns have been introduce to the model using the drain elemnets, spare charakteristics and local elements.
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Prediction of shotcrete behavior applying elastoplastic material model
Kejík, Vít ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
This work is focused on the application of advanced elasto-plastic material model intended for shotcrete. Spatial mathematical models of two laboratory tests are created, where this model is used. The first test is a three-point bending concrete specimen. Next, the behavior of the material is analyzed, in which input parameters are entered. Consequently, two reverse analyzes of the available data are analyzed where a match between prediction and measurement can be obtained. The second test is a modified tensile test, where is describe the material behavior in changing of input parameters. Subsequently, reverse data analysis is created, where an acceptable match between prediction and measurement is possible. In every study, the stress waveform in the fracture process zone is analyzed to more detail.
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Design of deep excavation on the street Provaznikova
Koudelková, Ivana ; Svoboda,, Petr (referee) ; Miča, Lumír (advisor)
This diploma thesis describes the design and static assessment carried shoring excavation pit for the construction of a multifunctional building in Brno Husovice. Introductory part summarizes the basic input information on the area of interest, including outputs of engineering-geological survey and gives an overview of the options pits. The main part describes the design and assessment of selected variant of shoring, the subsequent evaluation of the results and the technological progress of construction. The proposed design is complemented by structural calculations and construction plans.
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Application of fiber reinforcement to improve soil mechanical properties
Šindelářová, Daniela ; Miča, Lumír (referee) ; Chalmovský, Juraj (advisor)
The goal of this thesis was the summarization of available information about Fiber-reinforced soil. In the past, many of the previous works were published around the world. This thesis compares what type of fibres are in previous studies used – especially material, their size and amount in the Fiber-reinforced soil. All of these parameters were quite various, some of the sources used small-sized fibres, some used large-sized fibres. The most common material was polypropylene, although it was not the only one. For example, natural fibres, other synthetic materials, and waste materials can be mentioned. The amount of the fibres in the soil is measured in a few different ways, so in this thesis are these ways compared. It is necessary to run laboratory tests to quantify the effect of the fibres on the mechanical engineering properties of the soil. These tests are quite different compared to tests run on the unreinforced soil, so these differences are mentioned. The ways, how Fiber-reinforced soil was tested in different studies, are compared. From laboratory tests can be mentioned triaxial shear test, direct shear test and for Fiber-reinforced soil typical pullout test. At the end of this thesis are said and compared material models available for Fiber-reinforced soil design.
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