As civil engineering projects become increasingly ambitious, the earthworks that form a significant part of these projects become increasingly critical. Geotechnical engineering is concerned with the measurement , modelling and simulation of soil under various conditions for the application within civil engineering. In triaxial testing, an actuator applies a force or displacement to a soil sample. Dynamic triaxial testing is concerned with applying forces conforming to a rapidly changing pattern. The simplest case is concerned with applying a force in a sinusoidal pattern. The accuracy of models produced during triaxial testing depends largely on the accuracy of the equipment used for testing. As such, the control of the applied force is of great importance. The response of the soil sample directly influences the closed loop behaviour of the system. The soil sample response is unknown at the start of the test , can vary throughout a test and depends on various parameters, many of which are unobservable. This research investigates the issues faced in developing accurate control of dynamic triaxial testing equipment. Models of the load frame and various nonlinear soil sample responses are built for the purpose of simulation and controller design. Various control strategies are developed, implemented and tested, including the use of PID control, adaptive repetitive control and sliding mode control techniques. The recursive least squares algorithm is investigated and used for online identification in order to compensate for unknown and time varying plant parameters. Simulation and testing methods are investigated and several control methods are tested in simulation, on the target triaxial load frame using and finally using embedded processing hardware. Development and implementation techniques are also used including rapid prototyping and hardware-in-the-loop testing.

Orientador: Alberto Pio Fiori / Co-orientador: Ney Augusto Nascimento / Anexo: Mapa Geológico de Porto Alegre / Dissertação(mestrado)- Universidade Federal do Paraná. Setor de Ciências da Terra. Curso de Pós-Graduação em Geologia / Inclui bibliografia / Resumo: Este trabalho realizou estudos comparativos para testar a influencia de algumas variáveis geologico-ambientais na determinação da estimativa da capacidade de carga dos solos, através da aplicação de Standard Penetration Test (SPT) e Cone Penetration Test (CPT) na investigação geotécnica. Os estudos foram realizados em cálculos geotécnicos de capacidade de carga dos terrenos. As comparações utilizaram métodos de calculo recomendados por autores, e de uso intensivo e disseminado, de forma que se tornaram padrões na avaliação da capacidade de carga dos terrenos, e as clássicas comparações entre K (resistência de ponta do cone(qc)/numero de golpes das sondagens a percussão(N)) x profundidade e qc x N. Parâmetros de solos residuais e aluvionares de Porto Alegre e de Passo Fundo, no Rio Grande do Sul, foram utilizados. As metodologias utilizadas e os resultados obtidos indicaram que as razoes entre as resistências explicitadas pelas capacidades de carga calculadas por SPT e CPT são afetadas por variáveis geologico-ambientais, alem dos critérios granulométricos considerados nas interpretações. A natureza geológica dos terrenos apresentou maiores variações nas razoes K para os granitos tipo Morrinhos e menores variações para os granitos tipo Cerro Grande. Nas co-variáveis maturidade, condições geomorfológicas e influencia de uma zona de falha, testadas em solos derivados dos granitos tipo Cerro Grande, nos solos residuais de Porto Alegre, as variações de estimativa de capacidade de carga e dos diagramas K x profundidade e qc x N mostraram-se significativas, com variações estatisticamente relevantes em todos os cálculos e indicadores testados. Mesmo nos solos aluvionares em Porto Alegre, em terrenos para os quais o CPT foi originalmente projetado, as variações na aferição da resistência dos solos por SPT e CPT foram relevantes em diferentes tipos de aluvião, e ocorreram diferenças no dimensionamento das capacidades de carga; nos diagramas K x profundidade e nas razoes entre resistência de ponta do cone e numero de golpes das sondagens a percussão. Nos solos de Passo Fundo, os estudos demonstraram que o estagio de maturidade dos solos e as condições geomorfológicas foram fatores relevantes, para o mesmo tipo de solo, derivado da decomposição das rochas basálticas. As conclusões do trabalho indicaram que, para os terrenos considerados, as variáveis geologico-ambientais estudadas e, possivelmente, outras causas, precisam ser consideradas e monitoradas nos trabalhos para determinação mais adequada dos coeficientes de correlação e correção, responsáveis pelas interpretações geotécnicas. / Abstract: The objective of this study is to test the influence of some geological and environmental variables in the determination of load capacity of the soils, by the application of Standard Penetration Test (SPT) and Cone Penetration Test (CPT) in geotechnical investigation. The studies was realized in geotechnical data, and the comparison used calculation methods recommended and of intensive and disseminated use, that was standardized, for analysis of bearing capacity of piles, and the classical comparison between point resistance of cone penetration test and number of blows of standard penetration test. Residual and alluvial soils of Porto Alegre and Passo Fundo, in the Rio Grande of South were used. Comparision between K (point resistance of cone(qc)/number of blows of standard penetration test(N)) X profundity and qc X N. The methodologies followed and the results obtained indicate that the ratio between the bearing capacity of the piles analyzed, based on SPT and CPT borings, are affected by some geological and environmental variables, beyond grained criteria used in interpretations. Geological nature of terrains show better variations in K for soils derived from Morrinhos type granite, than soils derived from Cerro Grande type granites. In the co-variables maturity degree, geomorphological conditions e failed zone influence, tested in soils derived from Cerro Grande type granites, the variation of load capacity and of the K X profundity and qc X N diagrams are significative, with statistical relevant variation in all indicators tested and calculated. In the alluvial terrains, for that CPT was originally projected and developed, the variations on measure of soils by SPT and CPT are relevant and big differences occurred in the measure of resistance On the Passo Fundo soils, studies show that the degree of maturity of soils and geomorphologie conditions are a relevant factors, on the measure of soil resistance for pile load dimension, in soils derived from basaltic rocks. The results obtained indicate that factors such as geological fabric texture, maturity degree, geomorphological and alluvial soil conditions, among other, may influence, and must be considered for the determinations of the correlation and correction coefficients, used for geotechnical interpretations.