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Caracterização da resistência de um solo tropical a partir do ensaio de penetração dinâmica de cone com energia variável (panda) / Resistance characteristics of a tropical soil from a dynamic cone penetration test with variable power (panda)Diemer, Francielle 08 August 2014 (has links)
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Previous issue date: 2014-08-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Get soil resistance is critical to making any geotechnical design with confidence, thus,
laboratory tests are used to determine the strength and deformability of the ground in discrete
points involved in the volume of soil mass. Due to heterogeneity of soil formation is that field
trials are needed to supplement this determination and enrich the bank information. Field trials
were able to identify and estimate the mechanical parameters of the soil, an adequate prediction
of the behavior of retaining structures, excavation, foundation, floor sizing, etc., and determine
the characteristics of the soil profile, and have was used to estimate the mass of strength
parameters involved ground. In this sense a new tool for the characterization of the soil profile
from dynamic penetration of a metal cone with variable energy (PANDA) has been studied to
find a relationship with the strength parameters of a tropical soil obtained in a vertical slope of
about 4, 0 m high, located in Alexânia - GO with sandy visual tactile characteristics. Therefore,
we performed PANDA tests up to 4.0 meters and determining the moisture profile through a
survey to auger up to 3.70 meters and laboratory characterization tests were performed,
determining the strength parameters in natural moisture condition and flooded , deformation
parameters and determination of soil water characteristic curve (CCSA). PANDA the results
were compared with the laboratory tests for this ground and found a range of variation between
them always considering the trials of natural moisture condition. With the results it was possible
to see the influence of suction in the PANDA test. In terms of resistance parameters was
possible to find a friction angle of the relationship with the penetration of energy (qd) for this
soil. Overall the strength parameters showed the same trend as the qd values obtained by
PANDA compared with respect to depth. Finally, with the results it is recommended to carry
out further testing on different soil types in different humidity conditions to improve relations
found and increase the database. / Obter a resistência do solo é fundamental para elaborar qualquer projeto geotécnico com
confiança, sendo assim, ensaios de laboratório são usados para determinar a resistência e
deformabilidade do solo, em pontos discretos no volume da massa de solo envolvido. Devido
a heterogeneidade da formação do solo é que são necessários ensaios de campo para
complementar essa determinação e enriquecer o banco de informações. Os ensaios de campo
são capazes de identificar e estimar os parâmetros mecânicos do solo, para uma adequada
previsão do comportamento de estruturas de contenção, escavações, fundações,
dimensionamento de pavimentos, entre outros, além de determinar as características do perfil
do solo, e têm sido utilizados para estimar parâmetros de resistência do maciço de solo
envolvido. Nesse sentido uma nova ferramenta para caracterização do perfil do solo a partir de
penetração dinâmica de um cone metálico com energia varíavel (PANDA) foi estudado para
encontrar uma relação com os parâmetros de resistência de um solo tropical obtido em um
talude vertical de aproximadamente 4,0 m de altura, localizado em Alexânia – GO, com
características tatil visuais arenosas. Para tanto foram realizados ensaios de PANDA até 4,0
metros e determinação do perfil de umidade através de uma sondagem à trado até 3,70 metros
e em laboratório foram realizados ensaios de caracterização, determinação dos parâmetros de
resistência na condição de umidade natural e inundado, parâmetros de deformação e
determinação da curva característica solo água (CCSA). Foram comparados os resultados do
PANDA com os ensaios de laboratório para este solo e encontrou-se uma faixa de variação
entre eles sempre considerando os ensaios da condição de umidade natural. Com os resultados
encontrados foi possível ver a influência da sucção no ensaio PANDA. Em relação aos
parâmetros de resistência foi possível encontrar uma relação do ângulo de atrito com a energia
de penetração (qd) para este solo. No geral os parâmetros de resistência apresentaram a mesma
tendência que os valores de qd obtidos pelo PANDA quando comparados em relação a
profundidade. Por fim, com os resultados encontrados recomenda-se realizar mais ensaios com
diferentes tipos de solo em diferentes condições de umidade para melhorar as relações
encontradas e aumentar o banco de dados.
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Dynamic Cone Penetration Tests for Liquefaction Evaluation of Gravelly SoilsTalbot, Michael H 01 August 2018 (has links)
Dynamic Cone Penetration Tests for LiquefactionEvaluation of Gravelly SoilsMichael H. TalbotDepartment of Civil and Environmental Engineering, BYUDoctor of PhilosophyIn North American practice, the Becker Penetration Test (BPT) has become the primary field test used to measure penetration resistance of gravelly soils. However, this test is expensive and uncertainties exist regarding correlations and corrections for rod friction. As an alternative, the dynamic penetration test (DPT) developed in China has recently been correlated with liquefaction resistance in gravelly soils. The DPT equipment consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of 100 cm using 60 mm drill rod to reduce friction. The DPT is a very rugged, economical device, capable of penetrating dense gravel layers. During DPT field investigations following the 2008 Wenchuan earthquake in China, liquefaction resistance was correlated with DPT blow count.Dynamic Cone Penetration tests (DPT) tests were also performed adjacent to Becker Penetration test (BPT) sites at Pence Ranch, Whiskey Springs, and Larter Ranch in Idaho where gravel liquefaction was observed during the 1983 Mw6.9 Borah Peak earthquake. Companion DPT tests were performed using an automatic hammer at two energy levels, namely the energy specified in the original Chinese standard and the energy typical of SPT testing which would be easier to use in practice. Companion testing was undertaken to determine if the cone could be driven in gravelly soil with more standard drilling equipment available to geo-professionals. The second energy level also offers the potential to provide more resolution on the soil layering. PDA measurements were made to determine the energy transferred to the cone rods and the statistical variation in the energy transferred.Additionally, companion DPT tests were undertaken at the downstream toe of Millsite Dam near Ferron, Utah, where gravelly soils are predicted to liquefy in an earthquake. Two energy levels were used, one using an automatic hammer and the other a manual donut hammer. The blow counts from the BPT and DPT correlated reasonably well for gravels using the automatic hammer, but poor correlation was obtained with the donut hammer. Liquefaction resistance for the BPT and DPT soundings were also in reasonable agreement for gravel layers suggesting that the DPT can provide liquefaction hazard evaluations more economically than the BPT using direct correlations with field performance.Correlations suggest that the standard energy corrections developed for the SPT can be used for the DPT. In general, the liquefaction resistance from the BPT and DPT correlated reasonably well when using the 30% probability of liquefaction resistance curve developed for the DPT.Keywords: Michael H Talbot, liquefaction, Chinese dynamic penetration test, gravelly soils.
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