Two different concepts and design procedures namely settlement reducing piles and piled raft foundations have been studied independently in this thesis. A laboratory study is conducted on model rafts with differing number of model settlement reducing piles. Pile length, pile diameter, type of soil and size of raft are kept constant and settlements are measured under sustained loading. Remolded kaolin is consolidated under controlled stresses before tests are performed in model boxes. The tests are conducted under two sustained loadings of 75 kPa and 40 kPa. 0(raft), 16 and 49 number of piles are used. During the tests, all of the skin friction is mobilized. Several tests are conducted for each combination to see the variability. It is concluded that increasing the pile number beyond an optimum value is inefficient as far as the amount of settlement is considered. Also an analytical procedure has been followed to calculate settlements with increasing number of piles. In the second part of this thesis, finite element analyse have been performed on a piled raft foundation model, using Plaxis 3D Foundation Engineering software. This analyse are supported with analytical methods. The piled raft model is loaded with 450 kPa raft pressure. The studies are conducted in two sets in which different pile lengths are used / 25 m and 30 m respectively. The numbers of piles are increased from 63 to 143. All other parameters are kept constant. The results showed that again an optimum number of piles will be sufficient to reduce the settlement to the acceptable level. The analytical methods indicate a similar behavior. The comparison and results are presented in the study.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-20T11:13:08Z No. of bitstreams: 2 Dissertação - Tallyta da Silva Curado - 2015.pdf: 5629918 bytes, checksum: 52dabea4c56416cc72708f0af09a3640 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-20T11:16:53Z (GMT) No. of bitstreams: 2 Dissertação - Tallyta da Silva Curado - 2015.pdf: 5629918 bytes, checksum: 52dabea4c56416cc72708f0af09a3640 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-04-20T11:16:53Z (GMT). No. of bitstreams: 2 Dissertação - Tallyta da Silva Curado - 2015.pdf: 5629918 bytes, checksum: 52dabea4c56416cc72708f0af09a3640 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-08-27 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / With the expansion of urban areas, there is a tendency to vertical structures, with these being increasingly slim and constructed into smaller areas. In these cases, for it is often necessary to measure deep foundations, as piled foundations in order to resist high internal forces and with little available space, resulting in caps with many piles and next to each other, or even forming piled rafts. The influence of this high amount and proximity of piles cannot be neglected. To consider the effect of a pile in another, several theories have been formulated to better represent the interaction between piles, but there is not yet an established theory which results in factors that best represent the reality. In this way, this work aims to study existing methods in predicting the interaction factor between piles comparing results of analytical methods with numerical solutions. For this comparison was used the program of finite element method DIANA as a reference the values considered closer to the exact solution. The various theories are compared in accordance with the cases already reported in the literature, through the factors interaction between piles. Thus, it can be seen that the theories of Cao and Chen (2008) and Mylonakis Gazetas (1998) showed good agreement with the results of DIANA, but not in all cases of combination relative length (L/d) and relative stiffness (K), as Poulos and Davis (1980). And when one considers the possibility of having end-bearing piles, both Poulos and Davis (1980) and El Sharnouby and Novak (1990) overestimate, largely, the values from the finite element solution. However, this last is more precise in the condition of layered soil than the first theory. Furthermore, analyzes were performed by modeling with varying amounts of piles, in order to evaluate the influence of the presence of intermediate piles in the interaction between the piles. Thus, it was noted that there was increasing variation of factors interaction between piles with increasing amount of piles, such as when the piles are arranged concentrically and not more in line manner. Finally, settlements of pile groups are analyzed, in order to verify the difference between the settlements obtained via modeling by DIANA and through prediction method of settlement of pile groups. The latter analysis showed that small differences between the interaction factors between two piles could change the forecast of settlements by theoretical methods, causing representing differences. / Com a expansão dos centros urbanos, verifica-se a tendência de verticalização das estruturas, com estas sendo cada vez mais esbeltas e construídas em áreas menores. Com isso, por muitas vezes é necessário dimensionar fundações profundas, como as estaqueadas, de modo a resistir a altos esforços solicitantes e com pequena disponibilidade de espaço, implicando em blocos com muitas estacas, e próximos uns aos outros, ou mesmo formando radiers estaqueados. A influência dessa elevada quantidade e proximidade de estacas não pode ser desprezada. Para considerar o efeito de uma estaca em outra, várias teorias vêm sendo formuladas para representar melhor a interação entre estacas, mas ainda não há uma teoria estabelecida como a que resulta em fatores que representam melhor a realidade. Neste caminho, esse trabalho tem por objetivo estudar as metodologias existentes na previsão do fator de interação entre estacas comparando resultados de métodos analíticos com soluções numéricas. Para essa comparação foi utilizado o programa de Método dos Elementos Finitos DIANA como uma referência dos valores considerados mais próximos da solução exata. As diversas teorias são comparadas, de acordo, com os casos já apresentados na literatura, por meio dos fatores de interação entre estacas. Com isso, pode-se verificar que as teorias de Cao e Chen (2008) e Mylonakis e Gazetas (1998) tiveram boa concordância com os resultados do DIANA, mas não em todos os casos de combinação de comprimento relativo (L/d) e rigidez relativa (K), assim como Poulos e Davis (1980). E quando se considera a possibilidade de se ter estacas de ponta, tanto Poulos e Davis (1980) quanto El Sharnouby e Novak (1990) superestimam, em grande parte, os valores provenientes da solução de elementos finitos. Entretanto, esta última é mais precisa na condição de solo estratificado do que a primeira teoria. Ainda, foram realizadas análises por meio de modelagens com variadas quantidades de estacas, de modo a avaliar a influência da presença de estacas intermediárias na interação entre as estacas. Com isso, percebeu-se que há variação crescente dos fatores de interação entre estacas com o aumento da quantidade destas, assim como quando as estacas são dispostas de maneira mais concêntrica e não em linha. Por fim, recalques de grupos de estacas são analisados, visando verificar a diferença entre os recalques obtidos via modelagem pelo DIANA e por meio de método de previsão de recalque de grupos de estacas. Esta última análise demonstrou que diferenças pequenas entre fatores de interação entre duas estacas, podem alterar a previsão de recalques por métodos teóricos, provocando diferenças representativas.