Yuri Costa | UTFPR - UNIVERSIDADE TECNOLOGICA FEDERAL DO PARANÁ (original) (raw)
Papers by Yuri Costa
Revista Brasileira de Engenharia Agrícola e Ambiental
O objetivo deste trabalho foi avaliar a compressibilidade de um Argissolo Amarelo distrocoeso sub... more O objetivo deste trabalho foi avaliar a compressibilidade de um Argissolo Amarelo distrocoeso submetido a diferentes sistemas de manejo sob cultivo de cana-de-açúcar. O experimento foi realizado em áreas da Usina Triunfo Industrial, AL, onde se avaliaram os manejos: MA - mata nativa; MSI - manejo sem irrigação; MCI - manejo com irrigação e MCV - manejo com fertirrigação (vinhaça). Todas as áreas estudadas, exceto no MA, vêm utilizando o preparo convencional do solo com uso de grades pesadas. As amostras de solo foram coletadas nas profundidades de 0-20 e 20-40 cm. Trincheiras foram abertas nas quatro áreas de manejo em estudo, quando amostras de solo indeformadas foram retiradas com auxílio de aneis metálicos de 6,4 cm diâmetro e 2,5 cm de altura em cada profundidade. Após coletadas, as amostras foram saturadas e submetidas a sucções de 0,1 a 10 kPa; 50, 500 e 1500 kPa, levadas à prensa mecânica e realizado o ensaio de compressibilidade. A partir dos dados obtidos determinou-se a te...
Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering, 2017
The vast extension of a buried pipeline can lead to many specific situations involving longitudin... more The vast extension of a buried pipeline can lead to many specific situations involving longitudinal interactions with the surrounding soil, such as landslides, expansive soils, sinkholes, collapsible soils, just to name a few. In this study, three-dimensional numerical simulations were carried out to evaluate the mechanical behavior of a buried pipe undergoing a localized elevation. Parametric analyses were performed considering soil relative density, pipe-soil relative stiffness and vertical surcharge loading. The results of the parametric study are relevant to the design of buried pipes under the action of uplift forces.
This paper presents centrifuge tests performed to investigate the time-dependent deformations of ... more This paper presents centrifuge tests performed to investigate the time-dependent deformations of geotextile-reinforced soil walls. The models were built using nonwoven fabrics as reinforcement elements and a pure dry sand. Digital image analysis techniques were used to determine the displacement of sand markers placed along reinforcement layers in reduced-scale models. The instrumentation also included one LVDT to monitor the settlement at the top of the models and thermocouples to monitor the temperature inside the centrifuge. Two series of centrifuge tests were performed in this investigation. In some tests, designated herein as "short-term tests", the models were loaded until failure increasing the centrifugal acceleration. In the second series of tests, "long-term tests", the models were subjected to a constant acceleration and the wall deformations were observed with time. The results showed that the time-dependent behavior of reinforcement had an adverse effect on wall stability. RESUMO Este artigo apresenta ensaios em centrífuga realizados para investigar as deformações ao longo do tempo de muros de solo reforçado com geotêxteis. Os modelos foram construídos utilizando-se mantas não tecidas como elementos de reforço e uma areia pura. Técnicas para análise de imagens digitais foram usadas para determinar o deslocamento de marcos de areia dispostos ao longo das camadas de reforço nos modelos. A instrumentação foi ainda composta por um LVDT para monitorar os recalques no topo dos modelos e termopares para registrar a temperatura dentro da centrífuga. Duas séries de ensaios foram realizadas nesse estudo. Em alguns ensaios, designados como "ensaios de curto prazo", os modelos foram carregados até a ruptura, aumentando-se a aceleração centrífuga. Na segunda série, "ensaios de longa duração", os modelos foram submetidos a uma aceleração constante, observando-se a movimentação da estrutura ao longo do tempo. Os resultados mostraram que o comportamento dependente do tempo do reforço afetou a estabilidade do muro. 1.
Advanced Materials Research, Feb 6, 2014
The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engin... more The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engineering problems, namely low bearing capacity for shallow foundations and are not suitable as material for sub-base and road base. The use of this material in engineering practice needs improvement of their geotechnical properties. This paper investigates the effect of adding Portland cement to stabilize dune sand from the region of Natal, Brazil. Undrained triaxial tests were carried out to evaluate the effect of cement content on the geotechnical behaviour of dune sand-cement admixtures. Tests with admixtures with cement contents of 2.5, 5 and 10% of the dry mass of soil were carried out. Results showed that soil cohesion increased with increasing cement content. The friction angle of the admixtures was lower than that of the uncemented sand for cement content of 2.5 and 5% while It was larger than that of the uncemented sand for cement content of 10%.
Cintra pela valiosa orientação durante o desenvolvimento do presente trabalho. Aos colegas Benedi... more Cintra pela valiosa orientação durante o desenvolvimento do presente trabalho. Aos colegas Benedito Carneiro, Floriano Medeiros, Jeselay Cordeiro dos Reis, Mauro Menegotto, Nilton Campelo e Sidnei Teixeira, pelo inestimável apoio, principalmente com respeito ao árduo trabalho dispensado durante a execução das provas de carga. Aos professores Orencio Monje Vilar e Nelson Aoki pelas importantes sugestões fornecidas no decorrer do trabalho e no Exame de Qualificação. À Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP, pelo auxílio financeiro e pela concessão da bolsa de estudo. A todos os colegas, professores e funcionários do departamento de Geotecnia da USP/São Carlos pela cooperação.
Advanced Materials Research, 2013
This paper presents the results of centrifuge tests performed to investigate the behavior of geot... more This paper presents the results of centrifuge tests performed to investigate the behavior of geotextile-reinforced soil walls beyond stress conditions. The models were built using nonwoven fabrics as reinforcement layers and dry sand as backfill. Digital image analysis techniques were used to determine the displacement of sand markers placed along the reinforcements. The models were loaded until failure by increasing centrifugal acceleration, and the movements of the sand markers were used to determine the strain distributions along the reinforcement layers. The results revealed that stresses redistribute among reinforcement layers as models approach failure. Current design methods for GRS walls were found to be conservative when applied to predict the behavior of the reduced-scale models.
An experimental testing program is being conducted to evaluate the failure mechanisms of pipeline... more An experimental testing program is being conducted to evaluate the failure mechanisms of pipelines subjected to a localized loss of support. The program involves a series of centrifuge tests conducted to evaluate the response of pipes embedded in sand backfill and placed over a rigid trapdoor base that is released during testing. The tests involve a pipe with prototype diameter
Revista Brasileira de Engenharia Agrícola e Ambiental, 2010
O objetivo deste trabalho foi de avaliar a susceptibilidade a influência do manejo da cana-de-açú... more O objetivo deste trabalho foi de avaliar a susceptibilidade a influência do manejo da cana-de-açúcar sobre a compactação de um Argissolo Amarelo distrocoeso, através da densidade máxima (Dsmax) e umidade crítica (Uc) pelo ensaio de Proctor normal, e o grau de compactação em diferentes manejos e uso. O estudo foi realizado na Usina Triunfo Agroindustrial, Alagoas, em região composta de quatro subáreas, sendo: Área de mata (MA), Área de sequeiro (MSI), Área irrigada (MCI) e Área com vinhaça (MCV). Para a realização dos ensaios foram coletadas amostras indeformadas para densidade do solo e deformadas para matéria orgânica e ensaio de Proctor normal para obtenção da Dsmax e Uc e determinação do grau de compactação (GC) nos locais sorteados, 50 × 50 m, nas quatro áreas de manejo, nas profundidades de 0-20, 20-40 e 40-60 cm, com três repetições. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey, a 5% de probabilidade. Os valores das Dsmax do solo ...
2004 International Pipeline Conference, Volumes 1, 2, and 3, 2004
ABSTRACT
Advanced Materials Research, 2013
The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engin... more The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engineering problems, namely low bearing capacity for shallow foundations and are not suitable as material for sub-base and road base. The use of this material in engineering practice needs improvement of their geotechnical properties. This paper investigates the effect of adding Portland cement to stabilize dune sand from the region of Natal, Brazil. Undrained triaxial tests were carried out to evaluate the effect of cement content on the geotechnical behaviour of dune sand-cement admixtures. Tests with admixtures with cement contents of 2.5, 5 and 10% of the dry mass of soil were carried out. Results showed that soil cohesion increased with increasing cement content. The friction angle of the admixtures was lower than that of the uncemented sand for cement content of 2.5 and 5% while It was larger than that of the uncemented sand for cement content of 10%.
Polímeros, 2008
A utilização de materiais poliméricos designados por geossintéticos tem aumentando significativam... more A utilização de materiais poliméricos designados por geossintéticos tem aumentando significativamente nos últimos anos na Engenharia Civil. Para desempenhar adequadamente a função para a qual foram projetados, os geossintéticos devem ser submetidos a um rigoroso processo de controle de qualidade durante a fabricação. Discussões sobre a freqüência e os principais tipos de ensaios de laboratório utilizados nesse processo de controle para dois tipos de geossintéticos, os geotêxteis e as geomembranas, os materiais mais utilizados da famíla dos geossintéticos, são abordados no presente trabalho. As análises efetuadas com base em normas disponíveis no Brasil, nos EUA e na Europa mostram que no cenário nacional não há recomendações normativas sobre o controle de qualidade para a maioria das aplicações de geotêxteis e geomembranas, sendo o assunto pouco discutido na literatura técnica. No cenário internacional, as normas Européias se destacam como o conjunto de práticas mais completo para e...
Revista Brasileira de Ciência do Solo, 2010
O potencial produtivo da cana-de-açúcar decorre de fatores relacionados ao clima, ao solo e à var... more O potencial produtivo da cana-de-açúcar decorre de fatores relacionados ao clima, ao solo e à variedade cultivada. Sistemas de manejo que proporcionem a adição de resíduos orgânicos ao solo podem provocar alterações em seus atributos físicos, favorecendo o crescimento do sistema radicular e a produtividade da canade-açúcar. O objetivo deste trabalho foi avaliar os efeitos de diferentes sistemas de manejo com cana-de-açúcar com diversos níveis de adição de resíduos orgânicos sobre a distribuição e os índices de estabilidade de agregados de um Latossolo Amarelo distrocoeso dos tabuleiros costeiros de Alagoas. Foram selecionadas áreas em talhões de produção com a cultura da cana-de-açúcar: uma área cultivada sob sistema de manejo irrigado (SMI), uma área sob sistema de manejo de fertirrigação com vinhaça (SMV) e uma área sob sistema de manejo com aplicação de vinhaça + torta de filtro (SMVT). Esses sistemas de manejo foram comparados entre si e em relação a uma testemunha-padrão, repre...
Transportation Research Record, 2004
The tire shreds used in this research were produced with a hammer mill. The prototype embankment ... more The tire shreds used in this research were produced with a hammer mill. The prototype embankment was constructed within the premises of Front Range Tire Recycle, Inc., a recycling and storage facility located in Sedalia, Colorado. The typical dimensions of the tire shreds ranged from ...
Journal of Geotechnical and Geoenvironmental Engineering, 2009
An experimental testing program was undertaken to investigate failure mechanisms induced by the a... more An experimental testing program was undertaken to investigate failure mechanisms induced by the active movement of a deep rectangular trapdoor underlying a granular soil. Reduced-scale models were tested under normal gravity as well as under an increased gravitational field using a centrifuge facility. Some models were used to evaluate the performance of both flexible and rigid pipes undergoing a localized loss of support. Failure mechanisms in the longitudinal direction of the models were characterized by a single, well-defined failure surface that developed within the limits of the trapdoor. However, failure mechanisms in the transverse direction of the models were characterized by multiple failure surfaces extending outside the limits of the trapdoor. Significant dilation of the soil located immediately above the trapdoor was identified in the failure of the models. The pattern of the failure mechanisms was found to be affected by the stress level and backfill density. Higher stress levels were found to lead to well-developed failure zones. The influence of backfill density was found to be more relevant in models involving flexible pipes. Pipes embedded within loose backfill were severely damaged after loss of support, while pipes embedded in dense backfill experienced negligible deformations. These results indicate that damage to pipelines caused by ground loss of support can be significantly minimized by controlling the compaction of the fill.
Applied Mechanics and Materials, 2013
This paper investigates the behavior of a 15-m high multi-anchored bored pile wall built in a dun... more This paper investigates the behavior of a 15-m high multi-anchored bored pile wall built in a dune sand overlying a naturally occurring lateritic soil layer. A parametric study using the finite element method was carried out to model wall deflections and ground movements during construction phases. Deflection results from the numerical simulations were compared to data collected in the field. The maximum horizontal wall deflection shows a non-linear decreasing trend with increasing system stiffness. Embedment length was found to play a secondary role on wall deflections. Predicted horizontal wall deflections after preloading of second and third anchor layers were on average 30% smaller than the corresponding field values.
Revista Brasileira de Engenharia Agrícola e Ambiental
O objetivo deste trabalho foi avaliar a compressibilidade de um Argissolo Amarelo distrocoeso sub... more O objetivo deste trabalho foi avaliar a compressibilidade de um Argissolo Amarelo distrocoeso submetido a diferentes sistemas de manejo sob cultivo de cana-de-açúcar. O experimento foi realizado em áreas da Usina Triunfo Industrial, AL, onde se avaliaram os manejos: MA - mata nativa; MSI - manejo sem irrigação; MCI - manejo com irrigação e MCV - manejo com fertirrigação (vinhaça). Todas as áreas estudadas, exceto no MA, vêm utilizando o preparo convencional do solo com uso de grades pesadas. As amostras de solo foram coletadas nas profundidades de 0-20 e 20-40 cm. Trincheiras foram abertas nas quatro áreas de manejo em estudo, quando amostras de solo indeformadas foram retiradas com auxílio de aneis metálicos de 6,4 cm diâmetro e 2,5 cm de altura em cada profundidade. Após coletadas, as amostras foram saturadas e submetidas a sucções de 0,1 a 10 kPa; 50, 500 e 1500 kPa, levadas à prensa mecânica e realizado o ensaio de compressibilidade. A partir dos dados obtidos determinou-se a te...
Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering, 2017
The vast extension of a buried pipeline can lead to many specific situations involving longitudin... more The vast extension of a buried pipeline can lead to many specific situations involving longitudinal interactions with the surrounding soil, such as landslides, expansive soils, sinkholes, collapsible soils, just to name a few. In this study, three-dimensional numerical simulations were carried out to evaluate the mechanical behavior of a buried pipe undergoing a localized elevation. Parametric analyses were performed considering soil relative density, pipe-soil relative stiffness and vertical surcharge loading. The results of the parametric study are relevant to the design of buried pipes under the action of uplift forces.
This paper presents centrifuge tests performed to investigate the time-dependent deformations of ... more This paper presents centrifuge tests performed to investigate the time-dependent deformations of geotextile-reinforced soil walls. The models were built using nonwoven fabrics as reinforcement elements and a pure dry sand. Digital image analysis techniques were used to determine the displacement of sand markers placed along reinforcement layers in reduced-scale models. The instrumentation also included one LVDT to monitor the settlement at the top of the models and thermocouples to monitor the temperature inside the centrifuge. Two series of centrifuge tests were performed in this investigation. In some tests, designated herein as "short-term tests", the models were loaded until failure increasing the centrifugal acceleration. In the second series of tests, "long-term tests", the models were subjected to a constant acceleration and the wall deformations were observed with time. The results showed that the time-dependent behavior of reinforcement had an adverse effect on wall stability. RESUMO Este artigo apresenta ensaios em centrífuga realizados para investigar as deformações ao longo do tempo de muros de solo reforçado com geotêxteis. Os modelos foram construídos utilizando-se mantas não tecidas como elementos de reforço e uma areia pura. Técnicas para análise de imagens digitais foram usadas para determinar o deslocamento de marcos de areia dispostos ao longo das camadas de reforço nos modelos. A instrumentação foi ainda composta por um LVDT para monitorar os recalques no topo dos modelos e termopares para registrar a temperatura dentro da centrífuga. Duas séries de ensaios foram realizadas nesse estudo. Em alguns ensaios, designados como "ensaios de curto prazo", os modelos foram carregados até a ruptura, aumentando-se a aceleração centrífuga. Na segunda série, "ensaios de longa duração", os modelos foram submetidos a uma aceleração constante, observando-se a movimentação da estrutura ao longo do tempo. Os resultados mostraram que o comportamento dependente do tempo do reforço afetou a estabilidade do muro. 1.
Advanced Materials Research, Feb 6, 2014
The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engin... more The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engineering problems, namely low bearing capacity for shallow foundations and are not suitable as material for sub-base and road base. The use of this material in engineering practice needs improvement of their geotechnical properties. This paper investigates the effect of adding Portland cement to stabilize dune sand from the region of Natal, Brazil. Undrained triaxial tests were carried out to evaluate the effect of cement content on the geotechnical behaviour of dune sand-cement admixtures. Tests with admixtures with cement contents of 2.5, 5 and 10% of the dry mass of soil were carried out. Results showed that soil cohesion increased with increasing cement content. The friction angle of the admixtures was lower than that of the uncemented sand for cement content of 2.5 and 5% while It was larger than that of the uncemented sand for cement content of 10%.
Cintra pela valiosa orientação durante o desenvolvimento do presente trabalho. Aos colegas Benedi... more Cintra pela valiosa orientação durante o desenvolvimento do presente trabalho. Aos colegas Benedito Carneiro, Floriano Medeiros, Jeselay Cordeiro dos Reis, Mauro Menegotto, Nilton Campelo e Sidnei Teixeira, pelo inestimável apoio, principalmente com respeito ao árduo trabalho dispensado durante a execução das provas de carga. Aos professores Orencio Monje Vilar e Nelson Aoki pelas importantes sugestões fornecidas no decorrer do trabalho e no Exame de Qualificação. À Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP, pelo auxílio financeiro e pela concessão da bolsa de estudo. A todos os colegas, professores e funcionários do departamento de Geotecnia da USP/São Carlos pela cooperação.
Advanced Materials Research, 2013
This paper presents the results of centrifuge tests performed to investigate the behavior of geot... more This paper presents the results of centrifuge tests performed to investigate the behavior of geotextile-reinforced soil walls beyond stress conditions. The models were built using nonwoven fabrics as reinforcement layers and dry sand as backfill. Digital image analysis techniques were used to determine the displacement of sand markers placed along the reinforcements. The models were loaded until failure by increasing centrifugal acceleration, and the movements of the sand markers were used to determine the strain distributions along the reinforcement layers. The results revealed that stresses redistribute among reinforcement layers as models approach failure. Current design methods for GRS walls were found to be conservative when applied to predict the behavior of the reduced-scale models.
An experimental testing program is being conducted to evaluate the failure mechanisms of pipeline... more An experimental testing program is being conducted to evaluate the failure mechanisms of pipelines subjected to a localized loss of support. The program involves a series of centrifuge tests conducted to evaluate the response of pipes embedded in sand backfill and placed over a rigid trapdoor base that is released during testing. The tests involve a pipe with prototype diameter
Revista Brasileira de Engenharia Agrícola e Ambiental, 2010
O objetivo deste trabalho foi de avaliar a susceptibilidade a influência do manejo da cana-de-açú... more O objetivo deste trabalho foi de avaliar a susceptibilidade a influência do manejo da cana-de-açúcar sobre a compactação de um Argissolo Amarelo distrocoeso, através da densidade máxima (Dsmax) e umidade crítica (Uc) pelo ensaio de Proctor normal, e o grau de compactação em diferentes manejos e uso. O estudo foi realizado na Usina Triunfo Agroindustrial, Alagoas, em região composta de quatro subáreas, sendo: Área de mata (MA), Área de sequeiro (MSI), Área irrigada (MCI) e Área com vinhaça (MCV). Para a realização dos ensaios foram coletadas amostras indeformadas para densidade do solo e deformadas para matéria orgânica e ensaio de Proctor normal para obtenção da Dsmax e Uc e determinação do grau de compactação (GC) nos locais sorteados, 50 × 50 m, nas quatro áreas de manejo, nas profundidades de 0-20, 20-40 e 40-60 cm, com três repetições. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey, a 5% de probabilidade. Os valores das Dsmax do solo ...
2004 International Pipeline Conference, Volumes 1, 2, and 3, 2004
ABSTRACT
Advanced Materials Research, 2013
The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engin... more The dune sands of the coast of Rio Grande do Norte State, northeastern Brazil, have serious engineering problems, namely low bearing capacity for shallow foundations and are not suitable as material for sub-base and road base. The use of this material in engineering practice needs improvement of their geotechnical properties. This paper investigates the effect of adding Portland cement to stabilize dune sand from the region of Natal, Brazil. Undrained triaxial tests were carried out to evaluate the effect of cement content on the geotechnical behaviour of dune sand-cement admixtures. Tests with admixtures with cement contents of 2.5, 5 and 10% of the dry mass of soil were carried out. Results showed that soil cohesion increased with increasing cement content. The friction angle of the admixtures was lower than that of the uncemented sand for cement content of 2.5 and 5% while It was larger than that of the uncemented sand for cement content of 10%.
Polímeros, 2008
A utilização de materiais poliméricos designados por geossintéticos tem aumentando significativam... more A utilização de materiais poliméricos designados por geossintéticos tem aumentando significativamente nos últimos anos na Engenharia Civil. Para desempenhar adequadamente a função para a qual foram projetados, os geossintéticos devem ser submetidos a um rigoroso processo de controle de qualidade durante a fabricação. Discussões sobre a freqüência e os principais tipos de ensaios de laboratório utilizados nesse processo de controle para dois tipos de geossintéticos, os geotêxteis e as geomembranas, os materiais mais utilizados da famíla dos geossintéticos, são abordados no presente trabalho. As análises efetuadas com base em normas disponíveis no Brasil, nos EUA e na Europa mostram que no cenário nacional não há recomendações normativas sobre o controle de qualidade para a maioria das aplicações de geotêxteis e geomembranas, sendo o assunto pouco discutido na literatura técnica. No cenário internacional, as normas Européias se destacam como o conjunto de práticas mais completo para e...
Revista Brasileira de Ciência do Solo, 2010
O potencial produtivo da cana-de-açúcar decorre de fatores relacionados ao clima, ao solo e à var... more O potencial produtivo da cana-de-açúcar decorre de fatores relacionados ao clima, ao solo e à variedade cultivada. Sistemas de manejo que proporcionem a adição de resíduos orgânicos ao solo podem provocar alterações em seus atributos físicos, favorecendo o crescimento do sistema radicular e a produtividade da canade-açúcar. O objetivo deste trabalho foi avaliar os efeitos de diferentes sistemas de manejo com cana-de-açúcar com diversos níveis de adição de resíduos orgânicos sobre a distribuição e os índices de estabilidade de agregados de um Latossolo Amarelo distrocoeso dos tabuleiros costeiros de Alagoas. Foram selecionadas áreas em talhões de produção com a cultura da cana-de-açúcar: uma área cultivada sob sistema de manejo irrigado (SMI), uma área sob sistema de manejo de fertirrigação com vinhaça (SMV) e uma área sob sistema de manejo com aplicação de vinhaça + torta de filtro (SMVT). Esses sistemas de manejo foram comparados entre si e em relação a uma testemunha-padrão, repre...
Transportation Research Record, 2004
The tire shreds used in this research were produced with a hammer mill. The prototype embankment ... more The tire shreds used in this research were produced with a hammer mill. The prototype embankment was constructed within the premises of Front Range Tire Recycle, Inc., a recycling and storage facility located in Sedalia, Colorado. The typical dimensions of the tire shreds ranged from ...
Journal of Geotechnical and Geoenvironmental Engineering, 2009
An experimental testing program was undertaken to investigate failure mechanisms induced by the a... more An experimental testing program was undertaken to investigate failure mechanisms induced by the active movement of a deep rectangular trapdoor underlying a granular soil. Reduced-scale models were tested under normal gravity as well as under an increased gravitational field using a centrifuge facility. Some models were used to evaluate the performance of both flexible and rigid pipes undergoing a localized loss of support. Failure mechanisms in the longitudinal direction of the models were characterized by a single, well-defined failure surface that developed within the limits of the trapdoor. However, failure mechanisms in the transverse direction of the models were characterized by multiple failure surfaces extending outside the limits of the trapdoor. Significant dilation of the soil located immediately above the trapdoor was identified in the failure of the models. The pattern of the failure mechanisms was found to be affected by the stress level and backfill density. Higher stress levels were found to lead to well-developed failure zones. The influence of backfill density was found to be more relevant in models involving flexible pipes. Pipes embedded within loose backfill were severely damaged after loss of support, while pipes embedded in dense backfill experienced negligible deformations. These results indicate that damage to pipelines caused by ground loss of support can be significantly minimized by controlling the compaction of the fill.
Applied Mechanics and Materials, 2013
This paper investigates the behavior of a 15-m high multi-anchored bored pile wall built in a dun... more This paper investigates the behavior of a 15-m high multi-anchored bored pile wall built in a dune sand overlying a naturally occurring lateritic soil layer. A parametric study using the finite element method was carried out to model wall deflections and ground movements during construction phases. Deflection results from the numerical simulations were compared to data collected in the field. The maximum horizontal wall deflection shows a non-linear decreasing trend with increasing system stiffness. Embedment length was found to play a secondary role on wall deflections. Predicted horizontal wall deflections after preloading of second and third anchor layers were on average 30% smaller than the corresponding field values.