Yes / Three-dimensional finite element models were executed and validated to investigate the performance of buried flexible high-density Polyethylene (HDPE) pipes, in unreinforced and multi-geogrid-reinforced sand beds, while varying pipe burial depth, number of geogrid-layers, and magnitude of applied cyclic loading. Geogrid-layers were simulated considering their geometrical thickness and apertures, where an elasto-plastic constitutive model represented its behaviour. Soil-geogrid load transfer mechanisms due to interlocked soil in-between the apertures of the geogrid-layer were modelled. In unreinforced and reinforced cases, pipe burial depth increase contributed to decreasing deformations of the footing and pipe, and the crown pressure until reaching an optimum value of pipe burial depth. On the contrary, the geogrid-layers strain increased with increasing pipe burial depth. A flexible slab was formed due to the inclusion of two-geogrid-layers, leading to an increase in the strain in the lower geogrid-layer, despite its lower deformation. Inclusion of more than two geogrid-layers formed a heavily reinforced system of higher stiffness, and consequently, strain distribution in the geogrid-layers varied, where the upper layer experienced the maximum strain. In heavily reinforced systems, increasing the amplitude of cyclic loading resulted in a strain redistribution process in the reinforced zone, where the second layer experienced the maximum strain.

[pt] No presente trabalho foi estudado o comportamento de um muro de solo reforçado com 5m de altura e 1700m de extensão, construído como parte do dique que compõe o Depósito de Resíduos de Bauxita 7 da ALCOA Alumínio S.A. em Poços de Caldas, MG. Neste muro foram empregados um solo residual siltoargiloso obtido no local e geogrelhas. O muro foi instrumentado para medição de deslocamentos horizontais e verticais durante a construção. Na mesma área, também foi construído um aterro experimental de 2,6m de altura que permitiu a realização de 16 ensaios de arrancamento de grandes dimensões. Foram realizados ensaios de laboratório para definir os parâmetros de resistência e deformabilidade do solo. Os parâmetros obtidos foram empregados em simulações numéricas da construção do muro e dos ensaios de arrancamento pelo Método dos Elementos Finitos, utilizando-se o programa PLAXIS 2D v.8. Os resultados obtidos demonstraram que os deslocamentos ocorridos durante a construção do muro são comparáveis a valores reportados por outros autores. As previsões numéricas da construção do muro e dos ensaios de arrancamento apresentaram boa concordância com os resultados medido em campo. Constatou- se que a resistência ao arrancamento obtida foi superior às previsões baseadas em formulações tradicionais da literatura. / [en] The behavior of a 5m high and 1700m long reinforced soil wall was studied in this work. The wall constitutes the upper part of a dike constructed in Poços de Caldas-MG, Brazil, by Alcoa Aluminum S.A. to contain Bauxite residues. The wall was constructed using geogrids and a residual silty-clay. Two wall sections were instrumented. Horizontal and vertical displacements were monitored during construction. An 2.6m high experimental fill was constructed to conduct 16 large-scale pullout tests. Soil laboratory tests were conducted to define the strength and deformability parameters. The construction of the wall and the pullout tests were simulated using the PLAXIS 2D v.8 Finite Element Method code. The numeric predictions agree well with the field results. The measured horizontal displacements show good agreement with results reported by other authors and the pullout resistance was found to be greater than the values estimated by traditional methods.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-22T14:23:35Z No. of bitstreams: 1 KÊNIA ARAÚJO DE LIMA SCARIOT - DISSERTAÇÃO (PPGECA) 2018.pdf: 3614373 bytes, checksum: debef6a639457f042d11c7f1a33519ea (MD5) / Made available in DSpace on 2018-08-22T14:23:35Z (GMT). No. of bitstreams: 1 KÊNIA ARAÚJO DE LIMA SCARIOT - DISSERTAÇÃO (PPGECA) 2018.pdf: 3614373 bytes, checksum: debef6a639457f042d11c7f1a33519ea (MD5) Previous issue date: 2018-06-08 / Capes / Os movimentos de massa de solo em morros, taludes e encostas têm se intensificado nas últimas décadas. A região Nordeste lidera no Brasil o ranking de maior número de desabrigados afetados por problemas de instabilidade, uma vez que a ruptura de um maciço ocasiona danos materiais e perdas sociais e econômicas. Para mitigar os efeitos da instabilidade dos taludes são aplicadas técnicas de consolidação, melhoramento e reforços no intuito de gerar uma redistribuição global das tensões e deformações. Entre elas pode-se citar as técnicas como estabilização química e contenção com geossintéticos. A presente pesquisa teve por objetivo realizar um estudo paramétrico da resistência ao cisalhamento de um solo de baixa capacidade de suporte, no seu estado natural e após o emprego de técnica de estabilização química e da inserção de materiais de reforço (geotêxtil não-tecido e geogrelha). A pesquisa foi dividida em três etapas para atingir os fins propostos: caracterização do solo, estabilização química do solo e avaliação do comportamento mecânico do solo. Na primeira etapa foram realizados ensaios de caracterização física, química e mineralógica do solo. Na segunda fase foram realizados ensaios de compressão simples com o propósito de determinar um teor ótimo para a estabilização química do solo. Posteriormente submeteu-se amostras de solo natural, solo estabilizado e solos reforçados a ensaios de compressão triaxial não adensado e não drenado (UU), a fim de analisar os parâmetros geotécnicos de cada modelo e os ganhos de resistência e de rigidez dos solos melhorados em comparação ao solo natural. Em geral, os resultados indicaram que as inserções do geotêxtil não-tecido e da geogrelha contribuem para o aumento da resistência ao cisalhamento. A técnica de estabilização química do solo, comparada as técnicas de reforço com geossintéticos proporcionou melhor comportamento resistente, visto que a inserção do cimento ao solo promoveu resultados superiores de resistência ao cisalhamento do solo pesquisado. Entretanto, a presente pesquisa não considerou as vantagens técnicas, econômicas e ambientais de cada tecnologia, visto que estes aspectos podem inviabilizar as construções com solo melhorado. / Soil mass movements in hills, slopes and slopes have intensified in recent decades. The Northeast Region is the leader in Brazil of the highest number of homeless people affected by instability problems, since the rupture of a massif causes material damages and social and economic losses. To mitigate the effects of slope instability are applied consolidation techniques, improvement and reinforcement in order to generate a global redistribution of stresses and deformations. Among these may be mentioned the techniques as chemical stabilization and containment with geosynthetics. The objective of this research was to perform a parametric study of the shear strength of a soil with low support capacity, in its natural state and after the use of chemical stabilization technique and the insertion of reinforcement materials (non-woven geotextile and geogrid). The research was divided in three stages to reach the proposed ends: soil characterization, soil chemical stabilization and evaluation of soil mechanical behavior. In the first stage, physical, chemical and mineralogical characterization of the soil were performed. In the second phase, simple compression tests were carried out with the purpose of determining an optimum content for soil chemical stabilization. Subsequently, samples of natural soil, stabilized soil and reinforced soils were submitted to non-densified and non-drained triaxial (UU) compression tests in order to analyze the geotechnical parameters of each model and the strength and stiffness gains of the improved soils in compared to natural soil. In general, the results indicated that the insertions of the non-woven geotextile and the geogrid contribute to the increase in shear strength. The soil chemical stabilization technique, compared to the geosynthetic reinforcement techniques provided better resistant behavior, since the cement insertion in the soil promoted superior results of shear strength of the studied soil. However, the present research did not consider the technical, economic and environmental advantages of each technology, since these aspects can make feasible the constructions with improved soil.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-07-27T13:47:11Z No. of bitstreams: 2 Dissertação - Mateus Porto Fleury - 2018.pdf: 9102583 bytes, checksum: 40d5daa4efc28f9073bc7aace7846d2a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-07-27T13:55:25Z (GMT) No. of bitstreams: 2 Dissertação - Mateus Porto Fleury - 2018.pdf: 9102583 bytes, checksum: 40d5daa4efc28f9073bc7aace7846d2a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-07-27T13:55:25Z (GMT). No. of bitstreams: 2 Dissertação - Mateus Porto Fleury - 2018.pdf: 9102583 bytes, checksum: 40d5daa4efc28f9073bc7aace7846d2a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-05-11 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The impacts caused by waste generation from construction industry stimulate the adoption of techniques that made the recycled construction and demolition wastes (RCDW) an attractive filling material for the geotechnical purpose. The utilization of this new construction material with geosynthetics in reinforced soil structure (RSS) shows a promising path related to environmental and technical aspects, once the utilization of both materials can afford similar behavior as structures with natural aggregates. Despite this favorable scenario, it is essential to assess the mechanical damages on the reinforcement elements caused by the filling materials, which decrease its strength and compromise its behavior and functionality. In this way, this study aims to quantify the mechanical damages during installation caused by RCDW on geogrids by its reproduction in an experimental site plant. The site plant with precast concrete beams has been constructed to simulate constructive process of a RSS. Three different geogrids were adopted as reinforcement elements: one with polyvinyl alcohol (PVA) yarns and two with polyester (PET) yarns. Seven samples of RCDW were collected for laboratory technical characterization to assess the variability of the parameters relevant to the geotechnical application. It was investigated two installation damages mechanisms: i) launch height of the filling material, and ii) compaction procedures – with a vibratory roller and percussion equipment. Furthermore, it was evaluated the effects of a protection layer – with the same material (RCDW) – on the mechanical damages. The damages were quantified, with the adoption of statistical analysis, by reduction factors related to the ultimate tensile strength, as well as the modifications on the strain and stiffness (for 2% and 5% strains). The technical characterization of the RCDW samples revealed characteristics similar to gravels or sands, non-plastic behavior, and a considerable variability. The tensile strength reduction caused by compaction procedures prove to be more severe than the reductions caused by the launching height process. The abrasion damage can be considerate the major visual damage verified by the visual analysis of damaged specimens. It was concluded that the geogrids reduction factors caused by RCDW (related to installation damages) could be adopted to make feasible the utilization of these materials in RSS, taking in account the technical and environmental characteristics desired for this type of application. / Os impactos causados pelos resíduos da indústria da construção civil estimulam a adoção de técnicas de beneficiamento que tornam os resíduos de construção e demolição reciclados (RCD-R) atrativos como material de preenchimento em obras geotécnicas. Desse modo, a utilização conjunta desse novo material de construção com geossintéticos em estruturas de solo reforçado (ESR) mostra-se interessante quanto aos aspectos ambientais e técnicos, uma vez que o conjunto pode apresentar comportamento equivalentes aos de estruturas executadas com materiais convencionais. Contudo, apesar desse cenário positivo, faz-se fundamental investigar os danos mecânicos que o material de aterro pode causar ao elemento de reforço, o que pode contribuir para a diminuição de sua resistência e comprometer o seu desempenho e a sua funcionalidade. Nesse contexto, este estudo propôs quantificar os danos mecânicos de instalação gerados por RCD-R em geogrelhas por meio de sua reprodução em um experimento de campo. Para tanto, uma instalação experimental de peças pré-moldadas de concreto foi construída para simular os processos construtivos de uma estrutura de soloreforçado. Os elementos de reforço adotados consistiram de três diferentes tipos de geogrelhas – uma com fibra de álcool polivinílico (PVAL) e duas de poliéster (PET). Um total de sete amostras de RCD-R foram coletadas a fim de efetuar a sua caracterização em laboratório e verificar a variabilidade dos parâmetros de interesse para aplicação em obras geotécnicas. Buscou-se investigar a influência de dois condicionantes de dano de instalação: i) a altura de lançamento de material e ii) os processos de compactação – com rolo vibratório e à percussão. Investigou-se, também, o efeito do uso de uma camada de proteção – constituída do próprio RCD-R – nos danos mecânicos das geogrelhas. Os danos foram quantificados, com o auxílio de análise estatística, por meio de fatores de redução relacionados à resistência à tração de pico, assim como a alteração da deformação na ruptura e rigidezes (para deformações de 2% e 5%). A caracterização geotécnica das amostras de RCD-R revelou características semelhantes às observadas para solos pedregulhosos/arenosos, comportamento não plástico e variabilidade considerável. As reduções de resistência à tração decorrentes dos processos de compactação foram superiores em relação aos procedimentos de lançamento de material. As análises visuais das amostras danificadas revelaram que o dano de abrasão foi o principal dano visual observado. Conclui-se que os RCD-R apresentaram fatores de redução de resistência em geogrelhas, devido aos danos de instalação, que podem ser adotados de modo a viabilizar o uso destes materiais em ESR atendendo às caraterísticas técnicas e ambientais desejadas para esse tipo de obra.

La presente investigación tiene como objetivo el análisis del comportamiento de la geomalla biaxial extruida incorporada en un suelo granular a nivel de la sub-base para el pavimento que está ubicado en la av. Defensores de Morro en el distrito de Chorrillos, en el Departamento de Lima. Por ello, el procedimiento de esta investigación es realizar un programa experimental para el suelo en estudio e incluyendo la geomalla biaxial a nivel de la sub-base en dos diferentes posiciones una colocada en el medio y las dos capas en los extremos de la misma para encontrar la mejor alternativa que aumentara el valor del CBR del suelo para este tipo de suelo granular. La avenida en estudio presenta un tipo de suelo según clasificación SUCS de arena pobremente gradada con limo y grava. De acuerdo a los resultados obtenidos se observa que la geomalla incorporada en el medio mejora el CBR del suelo en un 6,5% y las colocadas en los extremos mejora el CBR del suelo en un 3,2%. La metodología utilizada para la investigación es del tipo de diseño experimental ya que se realizó un ensayo completo del suelo para determinar las características físicas y mecánicas necesarias, y conocer el valor del CBR de este suelo, cuyo valor fue muy importante para esta investigación, ya que con este se pudo saber si valor aumentaba favorablemente para una suelo granular. Teniendo como resultado que el valor de CBR ubicado en el medio de la capa sub-base mejora el valor del CBR en mayor porcentaje. / The present research aims to analyze the behavior of the extruded biaxial geogrid incorporated in a granular soil at the sub-base level for the pavement located in av. Defensores de Morro in the district of Chorrillos, in the Department of Lima. Therefore, the procedure of this research is to carry out an experimental program for the soil under study and including the biaxial geogrid at the sub-base level in two different positions, one placed in the middle and the two layers at the ends of it to find the best alternative that will increase the value of the soil CBR for this type of granular soil. The avenue under study presents a type of soil according to the SUCS classification of poorly graded sand with silt and gravel. According to the results obtained, it is observed that the geogrid incorporated in the middle improves the CBR of the soil by 6.5% and those placed at the ends improve the CBR of the soil by 3.2%. The methodology used for the research is of the type of experimental design since a complete test of the soil was carried out to determine the necessary physical and mechanical characteristics, and to know the value of the CBR of this soil, whose value was very important for this investigation, since that with this it was possible to know if the value increased favorably for a granular soil. As a result, the CBR value located in the middle of the sub-base layer improves the CBR value by a greater percentage. / Trabajo de investigación

En el presente estudio se determinó la capacidad portante que puede proporcionar la colocación de una geomalla de bambú en la interface de la base y subbase como estructura de reforzamiento. Seguidamente, se realizó una comparación de la capacidad portante del pavimento flexible convencional en estudio y el pavimento flexible con una geomalla biaxial y multiaxial de bambú. Para esto, se evaluó el pavimento flexible convencional actual de la avenida Bauzate y Meza en el Distrito de La Victoria y se tuvo que fabricar una geomalla con un material renovable como es el Bambú con las mismas dimensiones de las geomallas de polímeros de tipo Biaxial y Multiaxial. Entonces, para alcanzar los objetivos planteados, se realizaron ensayos en laboratorio que permitieron obtener los resultados con los que se generó las curvas esfuerzo/deformación para cada uno de los diseños de pavimentos analizados. Finalmente, las conclusiones del estudio demuestran un incremento en la capacidad portante del pavimento flexible convencional agregándole en el diseño una geomalla biaxial o multiaxial de bambú. Se presentan algunas recomendaciones a corto y mediano plazo para mejorar el desempeño de las geomallas de bambú en la construcción de pavimentos flexibles, así como incluir en la normativa peruana un método de diseño que permita sustentar el uso de estos elementos en los proyectos viales. / In the present study the bearing capacity that the placement of a bamboo geogrid at the interface of the base and subbase as reinforcement structure. Next, a comparison was made of the carrying capacity of the conventional flexible pavement under study and the flexible pavement with a biaxial and multiaxial bamboo geogrid. For this, the current conventional flexible pavement of Bauzate and Meza Avenue in the District of La Victoria was evaluated and a geogrid with a renewable material such as Bamboo with the same dimensions as the Biaxial-type polymer geogrids had to be manufactured. Multiaxial Then, to achieve the objectives set, laboratory tests were carried out that allowed to obtain the results with which the stress / strain curves were generated for each of the pavement designs analyzed. Finally, the conclusions of the study show an increase in the bearing capacity of the conventional flexible pavement by adding a biaxial or multiaxial bamboo geogrid to the design. Some short and medium term recommendations are presented to improve the performance of bamboo geogrids in the construction of flexible pavements, as well as to include in the Peruvian regulations a design method that allows to support the use of these elements in road projects. / Tesis

El presente proyecto de investigación tuvo por finalidad evaluar el uso del geocompuesto (geomalla Triaxial y geomembrana HDPE), como refuerzo en la interfaz subrasante-subbase de una estructura de pavimento flexible. Para ello, se propone un diseño de estructura de pavimento reforzado con geocompuesto en un tramo de la Av. Prolongación Defensores del Morro-Chorrillos que permita aumentar la capacidad de soporte de la subrasante, optimizar los espesores en las capas granulares, y prolongar la vida útil del pavimento. Con este propósito se planteó el diseño de una estructura de pavimento convencional y otra reforzada con geocompuesto para comparar y elegir el diseño más óptimo. La recolección de datos se realizó utilizando los formatos de clasificación vehicular del MTC, inspección visual de la vía, estudio de mecánica de suelos y análisis experimental. Luego del análisis de los datos recolectados se determinó que el PCI del tramo en estudio es de 21%, esto significa que el nivel de servicio de la vía es malo y necesita intervención. Por ello se realizó el diseño de tres alternativas de pavimento flexible: la primera alternativa es una sección convencional no reforzada, mientras que las otras dos alternativas consisten en secciones reforzadas con geomalla triaxial y geomembrana HDPE. Los resultados obtenidos muestran que el pavimento reforzado con geocompuesto y diseñado por el método Giroud-Han obtuvo un 47.62% de reducción en el espesor de la estructura del pavimento flexible con respecto al pavimento diseñado por el método AASHTO 93. Finalmente, luego de un análisis económico de las alternativas de diseño de pavimento flexible se concluye que el costo del pavimento reforzado con geocompuesto es 5.07% menor que el del pavimento tradicional (AASHTO 93). / The purpose of this research project was to evaluate the use of the geocomposite (Triaxial geogrid and HDPE geomembrane), as reinforcement in the subgrade-subbase interface of a flexible pavement structure. To do this, a design of a pavement structure reinforced with geocomposite is proposed in a section of Av. Prolongación Defensores del Morro-Chorrillos that allows increasing the support capacity of the subgrade, optimizing the thicknesses in the granular layers, and prolonging the life useful of the pavement. For this purpose, the design of a conventional pavement structure and another reinforced with geocomposite were proposed to compare and choose the most optimal design. Data collection was carried out using the MTC vehicle classification formats, visual inspection of the road, soil mechanics study and experimental analysis. After analyzing the data collected, it was determined that the PCI of the section under study is 21%, this means that the level of service of the road is bad and needs intervention. Therefore, the design of three flexible pavement alternatives was carried out: the first alternative is a conventional unreinforced section, while the other two alternatives consist of sections reinforced with triaxial geogrid and HDPE geomembrane. The results obtained show that the pavement reinforced with geocomposite and designed by the Giroud-Han method obtained a 47.62% reduction in the thickness of the flexible pavement structure with respect to the pavement designed by the AASHTO 93 method. Finally, after an economic analysis of the flexible pavement design alternatives, it is concluded that the cost of pavement reinforced with geocomposite is 5.07% lower than that of traditional pavement (AASHTO 93). / Tesis

Recent developments in constructions have heightened the need for protecting existing buried infrastructure. New roads and buildings may be constructed over already existing buried infrastructures e.g. buried utility pipes, leading to excessive loads threatening their stability and longevity. Additionally applied loads over water mains led to catastrophic damage, which result in severe damage to the infrastructure surrounding these mains. Therefore, providing protection to these existing buried infrastructure against increased loads due to new constructions is important and necessary. In this research, a solution was proposed and assessed, where the protection concept would be achieved through the inclusion process of geogrid-reinforcing layers in the soil cover above the buried infrastructure. The controlling parameters for the inclusion of geogrid-reinforcing layers was assessed experimentally and numerically. Twenty-three laboratory tests were conducted on buried flexible and rigid pipes under unreinforced and geogrid-reinforced sand beds. All the investigated systems were subjected to incrementally increasing cyclic loading, where the contribution of varying the burial depth of the pipe and the number of the geogrid-reinforcing layers on the overall behaviour of the systems was investigated. To further investigate the contribution of the controlling parameters in the pipe-soil systems performance, thirty-five numerical models were performed using Abaqus software. The contribution of increasing the amplitude of the applied cyclic loading, the number of the geogrid-reinforcing layers, the burial depth of the pipe and the unit-weight of the backfill soil was investigated numerically. The inclusion of the geogrid-reinforcing layers in the investigated pipe-soil systems had a significant influence on decreasing the transferred pressure to the crown of the pipe, generated strains along its crown, invert and spring-line, and its deformation, where reinforcing-layers sustained tensile strains. Concerning rigid pipes, the inclusion of the reinforcing-layers controlled the rebound that occurred in their invert deformation. With respect to the numerical investigation, increasing the number of the reinforcing-layers, the burial depth of the pipe and the unit-weight of the backfill soil had positive effect in decreasing the generated deformations, stresses and strains in the system, until reaching an optimum value for each parameter. Increasing the amplitude of the applied loading profile resulted in remarkable increase in the deformations, stresses and strains generated in the system. Moreover, the location of the maximum tensile strain generated in the soil was varied, as well as the reinforcing-layer, which suffered the maximum tensile strain. / Government of Egypt

Protection of buried pipes is a serious issue that concerns countries around the world. Therefore, there is a need for new soil improvement techniques such as geosynthetic materials installation to protect these pipes from damage. This study used large-scale laboratory tests to study the behaviour of buried pipes. A total of 22 large-scale tests were performed to study the behaviour of buried flexible HDPE pipes with and without void presence under the protection of the geogrid reinforcing layers subjected to incrementally increasing cyclic loading. The presence of voids located at the spring-line of the flexible buried pipes, led to a considerable increase in the soil surface settlement, pressure recorded at the pipe crown, spring-line and invert, pipe deformation and strain recorded in the pipe wall. Increasing the pipe burial depth contributed to significant reductions in the soil surface settlement, pressure recorded at the pipe crown and invert, pipe deformation and strain recorded in the pipe wall. However, the void presence limited the contribution of increasing the pipe burial depth. The inclusion of a geogrid reinforcing layer contributed to a considerable reduction in the soil surface settlement, pressure recorded at the pipe crown, spring-line and invert, pipe deformation and strain recorded in the pipe wall. The use of a combination of geogrid reinforcing layers and increasing the pipe burial depth contributed in diminishing the ground void presence effect, where better pressure distribution inside the system was achieved. Consequently, more protection was provided to the buried pipe.

The diploma thesis deals with using of reinforcing composite materials in asphalt layers. These geosynthetic materials are in road construction used especially to reduce spreading cracks and extend the service life of the construction. As par of this work, test specimens of different types of asphalt layers were produced. These samples were subjected to laboratory testing, where the results of different reinforced asphalt slabs were compared. Within the diploma thesis primarily deals with the testing of the shear bond strength between asphalt layers in order to determine what are the other influencing factors of the test. Another part of the thesis is the 4-point bending test, during which a special technology in the form of a DIC camera was used to monitor the behavior of the asphalt layer over time.