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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Modelagem num?rica de uma estrutura de conten??o de estacas espa?adas atirantadas em areia / Numerical modelling of an anchored contiguous bored pile wall in sand

Oliveira, Leonardo Henrique Borges de 17 October 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-15T18:06:09Z No. of bitstreams: 1 LeonardoHenriqueBorgesDeOliveira_DISSERT.pdf: 7126621 bytes, checksum: 718667a84d6f1efbe96c7b333ce46cec (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-30T17:33:43Z (GMT) No. of bitstreams: 1 LeonardoHenriqueBorgesDeOliveira_DISSERT.pdf: 7126621 bytes, checksum: 718667a84d6f1efbe96c7b333ce46cec (MD5) / Made available in DSpace on 2015-12-30T17:33:43Z (GMT). No. of bitstreams: 1 LeonardoHenriqueBorgesDeOliveira_DISSERT.pdf: 7126621 bytes, checksum: 718667a84d6f1efbe96c7b333ce46cec (MD5) Previous issue date: 2014-10-17 / Os projetos de estruturas de conten??o envolvem fatores de plastifica??o, carregamento e descarregamento de maci?os, protens?o, deslocamentos excessivos e empuxos de terra e ?gua. Al?m disso, a intera??o entre o solo contido e a estrutura executada ? bastante complexa e de dif?cil previs?o. Apesar do avan?o das t?cnicas de simula??o num?rica e monitoramento dos esfor?os e deslocamentos atrav?s de instrumenta??o, a formula??o dos projetos ainda se d? por m?todos cl?ssicos, cujas hip?teses simplificadoras podem superdimensionar os elementos constituintes. Neste trabalho, realizou-se um estudo num?rico tridimensional de uma estrutura de conten??o atrav?s do m?todo de elementos finitos (MEF). A estrutura de conten??o estudada ? composta por estacas espa?adas e tirantes. Os resultados num?ricos obtidos foram comparados a dados obtidos de uma instrumenta??o em campo. Avaliou-se a influ?ncia do posicionamento de uma ou duas linha de tirantes ao longo da profundidade e os efeitos causados pela execu??o de uma laje vinculada ? conten??o. Estudou-se, ainda, o fen?meno de arqueamento que ocorre entre as estacas, variando-se o espa?amento entre faces de estacas para estudar seus efeitos nas tens?es e deslocamentos horizontais. O estudo do posicionamento de uma linha de tirantes ativos indicou uma faixa compreendida entre 0,3 e 0,5 vezes a altura de escava??o como aquela que gera os menores deslocamentos horizontais da estrutura. O estudo com duas linhas de tirantes mostrou que a posi??o da linha superior no n?vel -2,05m e da linha inferior no n?vel -3,50m resulta nos menores deslocamentos horizontais. A laje vinculada ? conten??o diminuiu os deslocamentos horizontais em 0,14% vezes a profundidade de escava??o. Com rela??o ao arqueamento, as an?lises mostraram uma faixa ?tima de espa?amentos entre as faces das estacas compreendido entre e vezes o di?metro da estaca. / Retaining walls design involves factors such as plastification, loading and unloading, pre-stressing, excessive displacements and earth and water thrust. Furthermore, the interaction between the retained soil and the structure is rather complex and hard to predict. Despite the advances in numerical simulation techniques and monitoring of forces and displacements with field instrumentation, design projects are still based on classical methods, whose simplifying assumptions may overestimate structural elements of the retaining wall. This dissertation involves a three-dimensional numerical study on the behavior of a retaining wall using the finite element method (FEM). The retaining wall structure is a contiguous bored pile wall with tie-back anchors. The numerical results were compared to data obtained from field instrumentation. The influence of the position of one or two layers of anchors and the effects of the construction of a slab bounded at the top of the retaining wall was evaluated. Furthermore, this study aimed at investigating the phenomenon of arching in the soil behind the wall. Arching was evaluated by analyzing the effects of pile spacing on horizontal stresses and displacements. Parametric analysis with one layers of anchors showed that the smallest horizontal displacements of the structure were achieved for between 0.3 and 0.5 times the excavation depth. Parametric analyses with two anchor layers showed that the smallest horizontal displacements were achieve for anchors positioned in depths of 0.4H and 0.7H. The construction of a slab at the top of the retaining wall decreased the horizontal displacements by 0.14% times the excavation depth as compared to analyses without the slab. With regard to the arching , analyzes showed an optimal range of spacing between the faces of the piles between 0.4 and 0.6 times the diameter of the pile

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