Baigiamajame magistro darbe nagrinėjama gruntų morfologinės struktūros įtaka jų suspaudžiamumui. Darbą sudaro teorinė ir praktinė dalys. Teorinėje dalyje detaliai aprašomas gruntų morfologinės struktūros nustatymo tyrimams taikytas metodas, aptariami jo trūkumai ir privalumai, pateikiamos visos morfologiniams parametrams apskaičiuoti taikytos formulės. Atlikta gruntų morfologinės struktūros įtakos suspaudžiamumui teorijos apžvalga. Trumpai paaiškinama, pagal kokius kriterijus bandymams buvo pasirenkami gruntai. Praktinėje dalyje aprašomi gruntų granuliometrinės sudėties, morfologinės struktūros nustatymo bei spūdumo bandymų rezultatai. Išsamiai aprašoma kiekvieno praktinės dalies eksperimento eiga, problemos, su kuriomis buvo susiduriama darbo metu. Atlikta gautų rezultatų analizė, kurioje aptariama morfologinės struktūros įtaka gruntų suspaudžiamumui. Pagal šią analizę formuluojamos išvados ir teikiami pasiūlymai tolesniam darbui bei gautų rezultatų patikslinimui. Darbą sudaro 6 pagrindinės dalys: įvadas, literatūros apžvalga, eksperimentiniai tyrimai, rezultatų analizė, bendros išvados ir priedai. Darbo apimtis – 75 p. teksto be priedų, 43 p. priedų, 37 literatūros šaltiniai, 33 paveikslai ir 15 lentelių. / The master thesis purpose is to determine the influence of particle shape on the mechanical properties of sand. The work consists of theoretical and practical parts. The theoretical part describes the applied method for evaluating morphometric characteristics of particles. Also the discussion of advantages and disadvantages of this method and overview of theory of influence of particle shape on soil compressibility were made. Finally the criteria for choosing soils for research was discussed. In practical part of this thesis the results of experimental investigations were introduced. Firstly the evaluating of soil grading and estimation of morphometric characteristic of its particles were made. In order to determine the influence of morphometric characteristic on sands compressibility the oedometer tests was performed. Also there are introduced detailed courses of all experimental investigations and problems which have been encountered during processes. After all experimental investigations the analysis of results were made. According to this analysis, conclusions and proposals for further work and clarification of the results were obtained. The thesis consists of six basic parts such as introduction, literature review, experimental researches, analysis of researches data, conclusions and proposals, accessories. The final work consists of 75 p. of text without appendixes, 43 p. of appendixes, 37 bibliographical entries. 33 pictures, 15tables.

Submitted by Alfredo Lopes Saab null (alfredo.saab@hotmail.com) on 2017-02-01T17:00:09Z No. of bitstreams: 1 Alfredo Lopes Saab - Dissertacao.pdf: 12254886 bytes, checksum: 3adb2a1a44c1994fad82ff8230482cea (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-06T11:32:23Z (GMT) No. of bitstreams: 1 saab_al_me_bauru.pdf: 12254886 bytes, checksum: 3adb2a1a44c1994fad82ff8230482cea (MD5) / Made available in DSpace on 2017-02-06T11:32:23Z (GMT). No. of bitstreams: 1 saab_al_me_bauru.pdf: 12254886 bytes, checksum: 3adb2a1a44c1994fad82ff8230482cea (MD5) Previous issue date: 2016-12-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Nos solos não saturados mudanças sazonais de umidade ocorrem devido a ciclos de umedecimento e secagem. Tais mudanças dependem das características do solo e das condições climáticas da região, o que afeta a sucção no solo. Por esta razão, as propriedades dos solos não saturados dependem não apenas da história geológica e do ambiente de formação, mas também da variabilidade sazonal, fato que muitas vezes é negligenciado na prática da engenharia. Esta dissertação apresenta um estudo da influência da sucção na compressibilidade de um perfil de solo não saturado por meio de ensaios edométricos realizados em câmaras comuns e em câmaras que permitem o controle de sucção pela técnica de translação de eixos. Os ensaios foram realizados submetendo as amostras a trajetórias de carregamento-descarregamento com sucção constante. Parâmetros constitutivos mecânicos são apresentados e correlacionados ao longo da profundidade de acordo com as condições de campo. Os resultados indicam que a colapsibilidade e a variabilidade dos parâmetros são maiores na superfície do terreno, onde o solo interage com a atmosfera e, tende a decrescer com a profundidade e com a redução da sucção inicial no solo. O estudo realizado permite uma avaliação mais detalhada da colapsibilidade do solo e auxilia a interpretação de perfis de solos colapsíveis similares e de suas propriedades e parâmetros constitutivos. / Seasonal moisture content changes take place in the unsaturated soils as a result of wetting and drying cycles. These changes depend of soil characteristics and climatic conditions of the region, which affects the soil suction. Therefore, the properties of unsaturated soils depend not only on geological history and environment formation, but also the seasonal variability, a fact that is oftentimes neglected in engineering practice. This research presents an study of the influence of suction on compressibility of a collapsible unsaturated soil profile using conventional and suction controlled oedometer tests by the axis translation technique. The tests were performed submitting the specimen to loading-unloading paths under constant suction. Mechanical constitutive parameters are presented and correlated with the depth according to the in situ conditions. The results indicate that the soil collapsibility and the variability of constitutive parameters are greather on the ground surface, where the soil interacts with the atmosphere, and tends to decrease with depth and with the reduction of the initial soil suction. The study allow a more detailed evaluation of soil collapsibility and assist the interpretation of collapsible soils profiles and their properties and constitutive parameters.

Dissertação(mestrado)-Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia Oceânica, Escola de Engenharia, 2005. / Submitted by Lilian M. Silva (lilianmadeirasilva@hotmail.com) on 2013-04-25T18:33:16Z No. of bitstreams: 1 Um Modelo De Elementos Finitos Para A Análise Acoplada De Problemas De Adensamento Com Simetria Axial.pdf: 1681210 bytes, checksum: 23a6d094c0648352f349cac2829966de (MD5) / Approved for entry into archive by Cristiane Silva(cristiane_gomides@hotmail.com) on 2013-05-02T22:19:43Z (GMT) No. of bitstreams: 1 Um Modelo De Elementos Finitos Para A Análise Acoplada De Problemas De Adensamento Com Simetria Axial.pdf: 1681210 bytes, checksum: 23a6d094c0648352f349cac2829966de (MD5) / Made available in DSpace on 2013-05-02T22:19:43Z (GMT). No. of bitstreams: 1 Um Modelo De Elementos Finitos Para A Análise Acoplada De Problemas De Adensamento Com Simetria Axial.pdf: 1681210 bytes, checksum: 23a6d094c0648352f349cac2829966de (MD5) Previous issue date: 2005 / Este trabalho apresenta um modelo de elementos finitos para a análise de deformação e adensamento de maciços de solo sob condições de simetria axial. O ponto de partida são as equações diferenciais de governo que são resolvidas utilizando o método dos elementos finitos baseado no método dos resíduos ponderados adotando a formulação de Galerkin. As equações de governo são integradas sobre um domínio composto de elementos finitos quadrilaterais com quatro nós e produzem um sistema de equações algébricas em função dos deslocamentos e da poropressão. As equações de cada um dos elementos são somadas no sentido de obter um sistema global de equações. Resolver este sistema leva à solução do problema. A validação ocorre a partir da comparação com resultados de soluções analíticas baseadas na teoria da elasticidade, teoria do adensamento e ensaios de laboratório. Os resultados foram considerados satisfatórios e mostram diferenças que podem ocorrer em virtude das simplificações consideradas no modelo. / This work presents a finite element model for the analysis of soil strain and consolidation under axissymetric conditions. The starting point are the governing differential equations which are solved by using the finite element method based on the weighted residual method adopting Galerkin’s formulation. The governing equations are integrated over a domain composed of quadrilateral finite elements with four nodes and yield a set of algebraic equations in function of the displacement and of the pore pressure. The equations for each one of the elements are added in order to obtain a global system of equations. The solving of this system leads to the solution of the problem. The validation occurs through comparison with results of analytical solutions based on the elasticity theory, consolidation theory and laboratory tests. The results were satisfactory and show differences that may happen due to the simplifications taken in account in the model.

In any geotechnical design procedure, the fundemantal point to be initially clearified is the characterization of existing soil profile at a site. This requires a great deal of planning a suitable site investigation program including borings, sampling, laboratory and in situ testing etc. Laboratory and in-situ (field) tests are important tools leading to the estimation of soils properties in geotechnics. Beside laboratory tests, the measurement of engineering properties in situ is a continuously growing and developing trend, particularly in materials difficult to obtain perfect undisturbed samples. For the purpose of this study, two large volumed geotechnical investigation reports are collected from a wide archive of 30 years experiences. Different soil types are encountered during the study like alluvial deposits of soft to stiff cohesive materials, hard clays in appearance of highly weathered rocks. The in-situ tests mostly being focused and studied on are &ldquo / Pressuremeter Test&rdquo / and &ldquo / Standard Penetration Test&rdquo / on cohesive materails. Over 350 standard penetration test results are recorded together with the pressuremeter results of relevant soils. Besides, the corresponding laboratory test results of oedometer, triaxial loading and all index properties of soils are assembled. The results of in-situ tests are evaluated together with the results of laboratory tests performed on the samples obtained from related sites. The correlations between in-situ &amp / laboratory test results on shear strength, compressibility and deformation characteristics of soils are analysed and compared with the existing correlations in literature. The correlations are generally obtained to be in agreement with the ones in common literature in cases where the soil conditions, particularly saturation, are same in both laboratory and in-situ tests.

The use of coarse-grained fill materials has grown significantly in recent years especially on account of their use in dams and transportation networks. This study investigates compressibility of various coarse-grained fill materials in dry and wet loading conditions in oedometer test. Four materials were used in the experiments, which falls into GP, GW, GM and GC categories respectively. GP material is a weathered rock obtained from Eymir Lake region. This material was chosen especially to be able to investigate degradation and particle breakage due to compaction and compression. GW, GM and GC materials were obtained by using the material called &lsquo / bypass&rsquo / which is a fill material used in the construction of metro of Eryaman. Using these four materials, large-scale double oedometer tests were carried out to investigate compressibility in both dry and wet conditions. The double oedometer testing technique is used to investigate the effect of soaking on compressibility behaviour of compacted fill materials. Various compactive efforts were used in the compaction stage to investigate the effect of compactive effort on compressibility and degradation of the four gravelly materials. Gradations of the post-test samples were obtained and particle breakage due to compaction using various compactive efforts and particle breakage due to compression were determined. It is found that amount of compression does not necessarily depend on the dry density of the material and fine fraction is also a dominating property regarding the compressibility in coarse-grained fill materials. The vertical strains induced by soaking are on the order of 12% - 20% of the compression measured in dry loading case for the well-graded coarse-grained fill materials tested. Besides, there is significant particle breakage in the compaction process and no further particle breakage in the oedometer test for GP material.

Choice of the constitutive model and determination of input parameters are necessary for a successful application of numerical methods in geotechnical engineering. Higher complexity of modern constitutive models results in an increase of the number of input parameters and time requirements for their calibration. Optimization methods are a possible solution for this problem. An application in which metaheuristic optimization method Particle swarm optimization (PSO) is involved is presented in this thesis. Critical review and testing of various PSO alternatives was performed in the first part of this thesis. The most efective PSO alternatives were chosen. In the second part connection between PSO algorithm and finite element solver was prepared. Automatization of determination of constitutive models input parameters was performed on three boundary value problems: laboratory test (oedometer), in-situ test (pressuremeter) and geotechical construction (retaining wall). Three types of constitutive models are used. Linear elastic-perfectly plastic Mohr-Coulomb model, elastoplastic non-linear Hardening soil model and Hardening soil - small strain model.

This thesis has a theoretical and a practical part. The first part contains theoretical introduction to the phenomenon of increased stiffness at very small strains and possibilities of its practical applications. The available methods for evaluating initial shear modulus tests are described below. Increased attention is paid to the method of evaluation of test data in the frequency domain using the Fourier transform. The last chapter in this part describes an algorithm designed for automatic evaluation of measurements in the frequency domain. The practical part deals with measurement and evaluation of initial shear modulus for Brno clay as a function of vertical stress in oedometric test. Firstly, a device is presented that allows the extension of the oedometric test with sensors for measuring initial shear modulus of soil. This device was designed for the test in this thesis. Subsequently, the test plan is described including description of all soil samples. In this thesis, several types of soil samples from a single site were tested. Next, the results of the individual tests are evaluated by the selected methods. Examples are used for showing the differences in evaluation of the same data by other methods. At the end, the results of the individual tests for all sample types are compared with each other and with data from literature.