In the present thesis, studies on the response of soil nail walls subjected to static and seismic conditions using finite element based numerical simulations and the principle of reliability analysis have been performed. The basic methodology constitutes the study of various aspects of soil nail walls such as analyses of important external, internal and facing failure modes, development of axial forces, and displacement observations by considering various typical and prototype cases. For better understanding and presentation, subject matter of the thesis is organised in the following ten chapters. Chapter 1 of the thesis provides an introduction to the soil nailing technique and highlights some of its applications, advantages, and limitations. Chapter 2 provides a detailed review of existing literature on the soil nailing technique. Chapter 3 provides a detailed overview the various methodologies adopted in the thesis for the analyses and response study of the soil nail walls. Chapter 4 deals with the important aspects related to the plane strain finite element based numerical simulations of soil nail walls. In particular, addresses the implications of the use of advanced soil models and the consideration of bending stiffness of soil nails on the overall response of the soil nail walls. Chapter 5 presents finite element simulations based appraisal of the conventional design methodology of soil nail walls, and studies the response of typical soil nail walls under static and seismic conditions. Chapter 6 presents a reliability based study of the important failure modes of soil nail walls subjected to the variability in in-situ soil parameters, and highlights the importance of reliability analysis in context of soil nail walls. Chapter 7 proposes load and resistance factor design (LRFD) methodology in context of soil nail walls, and highlights the need in advancement of the existing conventional design methodology for soil nail walls. Chapter 8 illustrates the use of factorial design of experiment methodology in developing regression models for stability criteria analysis of soil nail walls. Chapter 9 proposes methods for assessing the adequacy of field pullout tests performed in accordance with the prevalent soil nailing guidelines. Further, a reliability based methodology is proposed for the evaluation and various applications of field pullout tests results have been illustrated. Chapter 10 summarises the various studies reported in the thesis and provides a few important conclusions. It is believed that the various studies reported in the thesis contribute to the enhancement of the existing knowledge on soil nailing technique, advancement in the analysis and design methods, and in general, are useful to the soil nailing practice.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-03-27T12:29:37Z No. of bitstreams: 2 Dissertação - Carla de Resende - 2014.pdf: 2346223 bytes, checksum: e2a510c6f6e95ab521cba058ea87a7cc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Rejected by Luciana Ferreira (lucgeral@gmail.com), reason: Erro de sistema no arquivo on 2015-03-27T12:38:21Z (GMT) / Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-03-27T12:50:40Z No. of bitstreams: 2 Dissertação - Carla de Resende - 2014.pdf: 2346223 bytes, checksum: e2a510c6f6e95ab521cba058ea87a7cc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-03-27T15:35:11Z (GMT) No. of bitstreams: 2 Dissertação - Carla de Resende - 2014.pdf: 2346223 bytes, checksum: e2a510c6f6e95ab521cba058ea87a7cc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-27T15:35:11Z (GMT). No. of bitstreams: 2 Dissertação - Carla de Resende - 2014.pdf: 2346223 bytes, checksum: e2a510c6f6e95ab521cba058ea87a7cc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-08-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Retaining structures with nails have been used in recent decades to contain excavation works in several Brazilian cities, including Goiânia. The nails are made of steel bars inserted in inclined or horizontal drilling, with small diameter and involved in cement grout, to ensure the stability of vertical excavations by frictional forces developed in the contact between the soil and nail. Therefore, it is important to understand this friction to design retaining structures. There are lots of calculation methods proposed by many authors to design nails and verify the stability of these structures. The main objective of this work was to review some calculation methods, conduct pullout tests in the field and laboratory tests with samples taken in situ, to evaluate calculation methodologies or parameters that best apply to the soil studied in Goiânia. Among several proposals to estimate the media shear stress in the soil-nail interface (qs) based on SPT, that showed better results in this paper are those from graph lower limit proposed by Ortigão e Palmeira (1997), Springer (2006) and a proposal based on Décourt & Quaresma (1978) to calculate pile lateral friction, using the proper parameter b. Other propositions based on soil type and parameters of the soil that showed good fits were Wong (1995) and Juran et al. (1990). The relation between qs and the shear stress of soil (ts) resulted values between 0,55 and 0,85. Displacement readings were performed during loading and unloading phase, was observed that for small loads, plastic deformations occured in the nail, so is recommended in cases of nail’s numerical analyzes adopt elastic-plastic models. Predictions of nail's elastic deformation, based on piles theory showed good results, however significant plastic deformation occured in nails. The results of shear tests were compared with the pullout tests, indicating that the reduction factor of laboratory results is necessary. / Estruturas de contenção com utilização de grampos têm sido cada vez mais empregadas nas últimas décadas com intuito de conter grandes escavações em diversas cidades brasileiras, incluindo Goiânia. Os grampos consistem em barras de aço introduzidas em perfurações inclinadas ou horizontais de pequeno diâmetro e posterior injeção de calda de cimento, de forma a garantir a estabilidade de escavações verticais pelas forças de atrito desenvolvidas no contato solo-grampo. Sendo assim, é fundamental o conhecimento deste atrito para o dimensionamento destas contenções. Existem vários métodos de cálculo propostos por diversos autores para o dimensionamento de grampos e verificação da estabilidade dessas estruturas. O objetivo principal deste trabalho foi o de revisar alguns desses métodos de cálculo, realizar ensaios de arrancamento em campo e também ensaios em laboratório com amostras retiradas de uma obra com múltiplos subsolos, para avaliar as metodologias de cálculo ou parâmetros que melhor se aplicam aos solos estudados da cidade de Goiânia. Dentre as diversas proposições para estimativa da tensão cisalhante média no contato sologrampo (qs) aquelas baseadas em ensaio SPT que obtiveram melhores resultados neste trabalho foram o limite inferior do gráfico proposto por Ortigão e Palmeira (1997), Springer (2006) e uma proposição baseada no Método Décourt e Quaresma (1978) para atrito lateral em estacas, com o ajuste adequado do parâmetro b. Outras proposições baseadas no tipo e parâmetros do solo que apresentaram bons ajustes foram Wong (1995) e Juran et al. (1990). Foram feitas comparações entre qs e a tensão cisalhante do solo (ts) encontrando para esta razão valores entre 0,55 e 0,85. Como foram realizadas leituras de deslocamentos tanto na fase de carregamento quanto na fase de descarregamento, notou-se que para pequenas aplicações de carga já acontecem deformações plásticas no grampo sendo recomendado nos casos de análises numéricas em grampos a adoção de modelos elasto-plásticos. As previsões de deformações elásticas dos grampos, baseadas em teorias de estacas apresentou uma boa aproximação dos ensaios, que entretanto apresentaram relevante deformação plástica nos ensaios realizados. Os resultados de ensaios de cisalhamento em amostras indeformadas dos solos foram comparados com os ensaios de arrancamento, indicando que o fator de redução dos resultados de laboratório é necessário.