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An?lise de estabilidade de fal?sias na zona costeira de Ba?a Formosa - RN / Analysis of cliffs stability at the coastal zone of Ba?a Formosa - RNSouza J?nior, Carlos de 20 December 2013 (has links)
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Previous issue date: 2013-12-20 / As mudan?as naturais e antr?picas que v?m ocorrendo na zona costeira em todo o mundo representam um dos maiores problemas para a sociedade neste s?culo. Essa import?ncia se torna mais evidente devido ? elevada densidade das cidades litor?neas, ? crescente especula??o tur?stico-imobili?ria dessas ?reas e ?s altera??es clim?ticas que tendem a desencadear e acelerar esses processos. Nesse contexto, percebe-se cada vez mais um aumento significativo dos problemas relacionados ? eros?o costeira e recuo de fal?sias no estado do Rio Grande do Norte. A ?rea de estudo desta pesquisa localiza-se na zona costeira do munic?pio de Ba?a Formosa/RN, no litoral oriental-sul do Rio Grande do Norte, e possui uma extens?o de cerca de 1200 m ao longo da praia do Porto. O objetivo principal deste trabalho ? analisar a estabilidade dessas fal?sias, atrav?s de investiga??es de campo, ensaios e an?lises computacionais utilizando o M?todo dos Elementos Finitos e o M?todo de Bishop. Para atender aos objetivos deste trabalho, a ?rea foi subdividida em quatro trechos, e foram aplicados checklists e tamb?m realizados ensaios de caracteriza??o e de cisalhamento direto com materiais obtidos ao longo desses trechos. Os segmentos de fal?sia nessa zona costeira possuem alturas variando em torno de 4 m e 14 m e inclina??es de aproximadamente 40? a 90?. Os solos constituintes das fal?sias foram classificados, em termos gerais, como areias argilosas ou siltosas e argilas arenosas, sendo os solos mais argilosos e variegados pertencentes ? base da fal?sia. As an?lises de estabilidade mostraram que os fatores de seguran?a variaram, no trecho 01, de 2,38 a 6,06, no trecho 02, de 1,01 a 1,62, no trecho 03, de 1,29 a 1,78, e no trecho 04, de 0,83 a 2,48. Assim, os trechos 02 e 03, foram considerados como mais inst?veis. Entretanto, pode-se considerar o trecho 03 como o mais cr?tico devido ? aus?ncia de estruturas de prote??o costeira e ? estreita faixa de praia. Fato que n?o ocorre no trecho 02, o qual possui uma extensa faixa de praia e ? protegido por um muro de arrimo que restringe o acesso dos banhistas ?s ?reas adjacentes do p? da fal?sia. / The natural and anthropogenic changes that are occurring at the coastal zone around the world represent the greatest problem to society in this century. This problem becomes more evident due to high density of coastal cities, to growing tourist-estate speculation of those areas and to climate change that tend to trigger and accelerate the erosive processes that operating in the littoral. In this context, it?s possible perceive ever more a significant increase of problems associated to the coastal erosion and retreat of cliffs in the state of Rio Grande do Norte, where this study area of this search is located. The area is located in the coastal zone of the city of Ba?a Formosa/RN, in south-eastern coast of Rio Grande do Norte, and has a extension of about 1200 meters along the Porto beach. The main objective of this study is to analyze the stability of these cliffs in this region. Through field investigations, testings and computational analysis using the Finite Element Method and Equilibrium Limit Methods. The area was divided into four sections, and were applied checklists, and also realized characterization tests and direct shear tests with materials obtained along these sections. In this manner, it was found that the segments of cliff in this coastal zone have heights around 4 meters to 14 meters and inclinations of approximately 40? to 90?.However the constituents soils of the cliffs were classified, in general terms in accordance to Unified Soil Classification System (USCS), as clayey sands or silty sands, clays of low plasticity, clayey gravels and poorly graduaded sands. The most variegated and clayey soils belong to base of the cliff. The stability analysis showed that the safety factors ranged in section 01, from 1.92 to 4.93, in the section 02, from 1.00 to 1.43, in the section 03, from 1.36 to 1.75 , and section 04, from 1.00 to 3.64. Thus, the sections 02 and 03 were considered more unstable. However, the section 03 can be considered as the most critical section due to the absence of coastal protection structures and the narrow strip of beach.
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Estabilidade das fal?sias da Barreira do Inferno - RN / Analysis of the stability of the sea cliffs of Barreira do Inferno - RNBarbosa, Nathalia Marinho 31 March 2017 (has links)
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Previous issue date: 2017-03-31 / Esta Disserta??o trata da obten??o das propriedades geot?cnicas de sedimentos da Forma??o Barreiras e da an?lise da estabilidade das fal?sias localizadas no Centro de Lan?amentos da Barreira do Inferno, munic?pio de Parnamirim, no estado Rio Grande do Norte. ?reas costeiras despertam um grande interesse pela popula??o em geral e empreendimentos nessas regi?es s?o bastante comuns, fazendo com que os processos erosivos precisem ser estudados a fim de proporcionar um maior entendimento dos fatores que influenciam na estabilidade das fal?sias e consequentemente na sua seguran?a. O local de estudo em quest?o, por ser uma ?rea militar protegida, encontra-se completamente livre de interfer?ncias humanas e sem nenhuma edifica??o em seu topo, fazendo com que as an?lises sejam representativas de condi??es naturais impostas aos taludes estudados. As atividades desenvolvidas durante a elabora??o desta disserta??o est?o agrupadas em quatro etapas: revis?o bibliogr?fica, trabalhos de campo, ensaios de laborat?rio e an?lise da estabilidade das fal?sias. Atrav?s de visitas realizadas na ?rea de estudo, foram colhidas informa??es necess?rias para a posterior obten??o dos perfis cr?ticos das fal?sias para an?lise de estabilidade. Foram observados que os perfis em geral n?o s?o ?ngremes, com a presen?a de incis?o basal em alguns trechos. Verificou-se nas an?lises que as tens?es de tra??o atuantes apresentam valores baixos. O principal mecanismo respons?vel por deflagrar os processos de instabilidade ? o aumento parcial da satura??o dos solos ocasionado pelas precipita??es pluviom?tricas, o que diminui sua resist?ncia e gera movimentos de massa. Pelos ensaios realizados observou-se que o intercepto de coes?o dos solos saturados ? em torno de 26% do valor obtido para os solos no teor de umidade natural. Contudo, os ?ngulos de atrito em ambos os casos sofrem inexpressivas varia??es. Concluiu-se que a presen?a da incis?o basal n?o apresentou efeitos significativos na redu??o da estabilidade nas configura??es analisadas pelos m?todos por Equil?brio-Limite, enquanto que pela an?lise de tens?es observa-se um aumento de tens?es de tra??o na face da se??o. O estudo da an?lise de estabilidade realizado neste trabalho representou efetivamente os tipos de ruptura observados nas fal?sias do litoral do Rio Grande do Norte, sendo bem mais coerentes que os obtidos pelos m?todos tradicionais. / This Dissertation treat of obtaining geotechnical properties of sediments of Barreiras Formation and the stability analysis of the cliffs located at the Barreira do Inferno Launches Center, Parnamirim, Rio Grande do Norte State. Coastal areas attracts great interest for the population in general, and developments in these regions are quite common, causing erosive processes to be studied in order to provide a better understanding of the factors influencing the Stability of the cliffs and consequently their safety. The study site in question, being a protected military area, is completely free of human interference and without any edification at its top, making the analysis representative of natural conditions imposed on the slopes studied. The activities developed during the elaboration of this dissertation are grouped in four stages: bibliographic revision, fieldwork, laboratory tests and stability analysis of the cliffs. Based on visits accomplished in situ, information was collected for the subsequent retrieval of the critical profiles of the cliffs for stability analysis. It was observed that the profiles in general aren?t steep, with the presence of basal incision in some areas. It was verified in analyzes that the tensile tensions acting are low. The main mechanism responsible for triggering the instability processes is the partial increase of soil saturation caused by rainfall, which decreases its resistance and generates mass movements. From the tests carried out, it was observed that the cohesion intercept of the saturated soils is around 26% of the obtained value in the natural moisture content. However, the angles of friction in both cases suffer inexpressive variations It was concluded that the presence of the basal incision had no significant effect on the reduction of stability in the configurations analyzed by the limit equilibrium methods, while stress analysis showed an increase in tensile stresses on the face of the section. The study of the stability analysis performed in this work effectively represented the types of rupture observed in the cliffs of the coast of Rio Grande do Norte, being more coherent than those obtained by traditional methods.
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Susceptibilidade ? ocorr?ncia de movimentos de massa e avalia??o da estabilidade de fal?sias sob condi??o n?o saturada: estudo de caso no centro de lan?amentos da barreira do inferno - Brasil / Susceptibility to the ocurrence of mass movements and evaluation of the stability of cliffs under unsa turated condition: case estudy in the center of launches from Barreira do Inferno ? BrazilTaquez, David Esteban Diaz 30 March 2017 (has links)
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Previous issue date: 2017-03-30 / Este trabalho tem por objetivo avaliar as condi??es de susceptibilidade a
ocorr?ncia de movimentos de massas e a estabilidade de encostas do Centro de
Lan?amentos da Barreira do Inferno (CLBI), mediante o m?todo da redu??o da
resist?ncia ou SRM (Strength Reduction Method), sob condi??es n?o saturadas no
Nordeste de Brasil. Para a an?lise da susceptibilidade a ocorr?ncia de movimentos de
massas foi utilizada a metodologia de processo de an?lise hier?rquica ou AHP
(Analytic Hierarchy Process) em combina??o com o uso dos sistemas de informa??o
geogr?fica SIG. A determina??o dos par?metros de resist?ncia dos solos, foi realizado
atrav?s de ensaios de compress?o triaxial tipo CU em condi??es saturadas, e ensaios
de compress?o triaxial tipo CW para a condi??o de umidade residual. Para a
determina??o das curvas de reten??o dos solos foi usado o m?todo do papel filtro, e
as equa??es de Chandler et al. (1992) e posteriormente foi realizado o ajuste das
curvas de reten??o pelo m?todo de Van Genuchten (1980). A partir dos resultados de
ensaios triaxiais, foi ent?o, realizada a previs?o da resist?ncia ao cisalhamento dos
solos n?o saturados a partir do modelo hiperb?lico proposto por Vilar (2007). A partir
das se??es suscept?veis ? ocorr?ncia dos movimentos de massa e dos par?metros de resist?ncia dos solos estudados, foram realizadas an?lises da estabilidade das
encostas a fim de quantificar o fator de seguran?a das mesmas. O m?todo utilizado
nas an?lises de estabilidade foi o SRM, implementado no Software OPTUM,
considerando diferentes condi??es de satura??o, a saber: solos sob condi??o natural
de campo, solo com 50% do grau de satura??o e, por fim, considerando o solo
completamente saturado. Nas an?lises foram consideradas tamb?m a presen?a de
camadas de solo cimentado e fendas de tra??o presentes no topo da fal?sia. Ao todo
a encosta foi subdividida em tr?s solos predominantes, os quais est?o posicionados
na base, na se??o intermedi?ria e no topo da fal?sia, denominados solo-1, solo-2 e
solo-3, respectivamente. Estes solos foram caracterizados como areia argilosa (SC),
areia Silto-Argilosa (SM), areia mal graduada (SP). Quanto as curvas de reten??o, os
tr?s solos apresentam comportamento bimodal, t?picas de solos com granulometrias
de material com macroporos e microporos. Finalmente os resultados obtidos destas
an?lises num?ricas, foram relacionados inicialmente com o modelo de
susceptibilidade produzido a partir da metodologia AHP-SIG, concluindo que este
modelo encontra-se em boa concord?ncia, evidenciado pelos resultados das an?lises
num?ricas e pelos vest?gios de movimentos vistos em campo. Os resultados das
an?lises tamb?m foram relacionados com os tipos de movimentos de massa,
concluindo que tanto os fatores geomorfol?gicos, quanto os graus de satura??o
resultam em diferentes tipos de movimentos para se??es caracter?sticas pr?prias
destas geomorfologias (fal?sias), verificando desta forma os movimentos sugeridos
nos estudos de Santos Jr et al.(2004) e Souza J?nior (2013), onde foram relacionados
tr?s tipos de perfis com diferentes morfologias e seus poss?veis movimentos de
massa, tombamentos, quedas de blocos e escorregamentos. / The aim of this research is to evaluate the susceptibility conditions to the
occurrence of mass movements and slope stability of the Center of Launches from
Barreira do Inferno (CLBI) using the method of Strength Reduction Method ou SRM,
on unsaturated conditions in the Northeast of Brazil. The analysis of the susceptibility
to the occurrence of mass movements, the methodology called the Analytic Hierarchy
Process was used along with the GIS geographic information systems. In order to
determine the resistance parameters of the soils, triaxial compression tests were
carried out under saturated conditions CU and triaxial compression tests CW were
performed for the residual moisture condition. The determination of soil retention
curves, the filter paper method was considered, equations by Chandler et al. (1992),
and the adjustment of the retention curves developed by Van Genuchten (1980). From
the results of the triaxial tests, the prediction of the shear strength of the unsaturated
soils was performed using the hyperbolic model proposed by Vilar (2007). Then, from
the susceptible sections to the occurrence of mass movements and the resistance
parameters of the studied soils, analyzes of slope stability were applied with the
intention of quantify the safety factor of the same. The method used in the stability analyzes was the SRM, implemented in the OPTUM Software, considering different
saturation conditions, as follows: soil under natural field saturation condition, soil with
50% degree of saturation, and finally Completely saturated soil. The analysis also took
into account the presence of layers of cemented soil and traction cracks present in the
upper part of the cliff. The slope was divided into three sections with predominant soils,
which were positioned at the base of the intermediate section, and at the top of the
cliff, called soil-1, soil-2, and soil-3 respectively. These soils were characterized as
clayey sand (SC), silty sand (SM) and poorly graded sand (SP). As for the retention
curves, the three soils present bimodal behavior, typical of soils with granulometry of
material with micropores and macropores. Finally, the results obtained from these
numerical analyzes were initially related to the model of susceptibility produced from
the AHP-GIS methodology, concluding that this model is in good agreement,
evidenced by the results of the numerical analysis and by the vestiges of Movements
observed in the field. The results of the numerical analyzes were also related to the
types of mass movements, presenting as an outcome that both geomorphological
factors and degrees of saturation result in different types of movements for the
characteristic sections of these geomorphologies (cliffs). Verifying in this way the
movements suggested in the studies of Santos Jr et al. (2004) and Souza Junior
(2013), where three types of profiles with different morphologies and their possible
mass movements, toppling, fall of blocks and landslides were related.
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