Indiana University-Purdue University Indianapolis (IUPUI) / In this thesis, an explicit time integration code which integrates multibody dynamics (MBD) and the discrete element method (DEM) is validated using three previously published steady-state physical experiments for non-cohesive sand-type material, namely: shear-cell for measuring shear stress versus normal stress; penetroplate pressure-sinkage test; and wheel drawbar pull-torque-slip test. The test results are used to calibrate the material properties of the DEM soft soil model and validate the coupled MBD-DEM code. All three tests are important because each test measures specific mechanical characteristics of the soil under various loading conditions. Shear strength of the soil as a function of normal load help to understand shearing of the soil under a vehicle wheel contact patch causing loss of traction. Penetroplate pressure-sinkage test is used to calibrate and validate friction and shear strength characteristics of the soil. Finally the rigid wheel-soil interaction test is used to predict drawbar pull force and wheel torque vs. slip percentage and normal stress for a rigid wheel. Wheel-Soil interaction test is important because it plays the role of ultimate validation of the soil model tuned in the previous two experiments and also shows how the soil model behaves in vehicle mobility applications. All the aforementioned tests were modeled in the multibody dynamics software using rigid bodies and various joints and actuators. The sand-type material is modeled using discrete cubical particles. A penalty technique is used to impose normal contact constraints (including particle-particle and particle-wall contact). An asperity-based friction model is used to model friction. A Cartesian Eulerian grid contact search algorithm is used to allow fast contact detection between particles. A recursive bounding box contact search algorithm enabled fast contact detection between the particles and polygonal body surfaces (such as walls, penetrometer, and wheel). The governing equations of motion are solved along with contact constraint equations using a time-accurate explicit solution procedure. The results show very good agreement between the simulation and the experimental measurements. The model is then demonstrated in a full-scale application of high-speed off-road vehicle mobility on the sand-type soil.

Den finkorniga sulfidjorden som finns längs Norrlandskusten är känd för sin stora sättningsbenägenhet och utgör en potentiell miljörisk genom försurning och urlakning av metaller om den inte hanteras rätt. För att förebygga miljörisker och utveckla jordförstärknings- och grundläggningsmetoder måste en ökad kunskap om sulfidjordar tas fram. I ett pågående forskningsprojekt vid Statens Geotekniska Institut studeras sulfidjords kompressionsegenskaper och rekommendationer ska tas fram avseende underlag för sättningsberäkningar. I projektet omfattas ett antal provbankar där ett av dessa områden, Lampen ligger i Kalix i norra Sverige. I detta examensarbete har det utförts numeriska analyser i finita elementprogrammet PLAXIS 2D av sättningar och portryck under en av provbankarna i Lampen och jämförelser görs med tidigare rapporterade fältmätningar. Tre olika delar analyseras i FE-programmet PLAXIS 2D. I den första delen, som är huvuddelen, utvärderas materialmodellernas, Soft Soil (SS) respektive Soft Soil Creep (SSC), förmåga att simulera de uppmätta sättningarna och porövertrycken för en period av cirka ett års belastning av provbank. Den andra delen består av en analys av de två deformationstillstånden, axialsymmetriskt och plant. De två deformationstillståden jämförs med hänsyn till sättningar och portryck. I den tredje delen utvärderas påverkan på simulerade resultat av olika nivåer på grundvattenytan, en variation som har observerats i provområdet i Lampen. Vid en jämförelse av de konstitutiva modellerna noteras som förväntat större sättningar vid användning av SSC-modellen i jämförelse med SS-modellen. SSC-modellen visar även ett högre porövertryck. Vid jämförelse med i fält uppmätta värden noteras att de mest överensstämmande sättningarna erhålls från SS-modellen medan portrycksutvecklingen simuleras bättre, men ändå långt från bra, med SSC-modellen (för simulering med dubbelsidig dränering). Vid analys av deformationstillstånd (axialsymmetriskt kontra plant) noteras en jämnare fördelning av deformationer längs banken vid användandet av axialsymmetriskt tillstånd. Den potentiella brottrörelsen som uppvisas vid släntkrön vid tillämpning av plant deformationstillstånd är inte lika tydlig vid axialsymmetriskt tillstånd. Det axialsymmetriska tillståndet visar även ett lägre porövertryck. Numeriska simuleringar av den varierande nivån på grundvattenytan som observerats i fältmätningar visar vid fallet en lägre antagen grundvattennivå en marginellt mindre sättning.  Potentiella brottrörelser blir inte lika tydliga då den lägre nivån på grundvattenytan simuleras.

A significant number of studies address various aspects related to tire modeling; most are dedicated to the development of tire models for on-road conditions. Such models cover a wide range of resolutions and approaches, as required for specific applications. At one end of the spectrum are the very simple tire models, such as those employed in real-time vehicle dynamic simulations. At the other end of the spectrum are the very complex finite element models, such as those used in tire design. In between these extremes, various other models have been developed, at different levels of compromise between accuracy and computational efficiency. Existing tire models for off-road applications lag behind the on-road models. The main reason is the complexity added to the modeling due to the interaction with the soft soil. In such situations, one must account for the soil dynamics and its impact on the tire forces, in addition to those aspects considered for an on-road tire. The goal of this project is to develop an accurate and comprehensive, while also efficient, off-road tire model for soft soil applications. The types of applications we target are traction, handling, and vehicle durability, as needed to support current army mobility goals. Thus, the proposed approach is to develop a detailed semi-analytical tire model for soft soil that utilizes the tire construction details and parallels existing commercially available on-road tire models. The novelty of this project relies in developing a three-dimensional three-layer tire model employing discrete lumped masses and in improving the tire-soil interface model. This will be achieved by enhancing the resolution of the tire model at the contact patch and by accounting for effects and phenomena not considered in existing models. / Master of Science

The main goal of this study is to improve the understanding of the interaction between a pneumatic tire and deformable terrain. A design of experiments has been implemented, that gives insight into the effect of individual tire and soil parameters, specifically wheel slip, normal load, inflation pres-sure, and soil compaction, as well as into the effect of combinations of such parameters on the tire and soil behavior. The results of such test data is exceedingly relevant, providing significant infor-mation to tire design for tire manufacturers, to users for operating conditions selection, as well as providing modeling parameters for tire models. Moreover, experimental investigation of tire-soil interaction provides validation data for tire models operating under similar conditions. In support of the validation of a soft soil tire model currently being developed at Virginia Tech under the auspices of the Automotive Research Center, experimental work has been performed on a low-speed, indoor single-wheel tester built to investigate studies in terramechanics. The terramechanics rig provides a well-controlled environment to assure repeatable testing conditions and void vehicle component ef-fects. The test tire for the rig is instrumented with a wireless sensory system that measures tire de-flection at the contact patch; combining this system with other instruments of the rig allows accurate estimations of wheel sinkage. A methodical soil preparation procedure has rendered great data to analyze several relations, such as the drawbar pull and the sinkage dependency on slip. The data col-lected indicated that, when looking at the effect of individual parameters, by increasing the soil com-paction, the normal load, and by decreasing the inflation pressure will result in a higher normalized drawbar pull. A higher normal load under all conditions consistently lowered the max tire sinkage depth. The sinkage has increased dramatically with the slip ratio, growing threefold larger at high slip (70-90%) when compared to lower slip (0-5%) ratios. / Master of Science

A numerical formulation for two-dimensional electro-osmotic consolidation in soft clays was derived from the basic equations of fluid flow, current flow and virtual work law. And, a well known elasto-plastic soil model, Modified Cam Clay was embedded into the formulation and implemented into the finite element program AFENA. The formulation was evaluated by comparing the predicted settlement and pore water pressure response with the values obtained from laboratory tests. The tests were conducted in an electro-osmotic triaxial apparatus, which was modified from a standard triaxial apparatus to facilitate electro-osmotic consolidation and required measurements. A series of electro-osmotic consolidation tests under different initial stress conditions were conducted to evaluate the finite element model and very good agreements between the observed and predicted results were observed. Another set of electro-osmotic tests were conducted with the similar initial stress, but different boundary conditions to examine the effects of electrochemical changes during the electro-osmosis. The study showed an apparent increase in the preconsolidation pressure and alteration in the coefficient of consolidation as a result of the electrochemical changes. A one-dimensional electro-osmotic consolidation problem was simulated and analysed, and the settlement and pore water pressure responses were compared with the solutions obtained from Esrig's (1968) one-dimensional theory. Another problem involving combined electro-osmotic and direct loading consolidation was also analysed and the results were compared with the solutions obtained from Wan and Mitchell's (1976) theory. Excellent matches were observed in both cases mentioned above for constant values of electro-osmotic and hydraulic permeabilities. However, the effects of varying electro-osmotic and hydraulic permeabilities, which are practically far more significant and not adopted in the theories mentioned above, were also analysed and the results presented. An attempt was made to simulate and analyse one of the successful field trial of electro-osmotic stabilisation conducted by Bjerrum et al (1967) on Norwegian quick clay. Good agreement between the predicted and reported settlement was observed for the first 50days of the treatment period. However, the model over-predicted the settlement after this period and the possible causes for this variation are discussed.

De nombreux tremblements de terre ont provoqué l’effondrement de structures importantes. La conception des structures résistant aux séismes dépend fortement de l’interaction sol-fondation-structure. Cette interaction implique la prise en compte simultanée des mouvements relatifs et des mécanismes de transfert de charge. En ce qui concerne les sols liquéfiables, la génération des pressions interstitielles doit également être prise en compte.Le renforcement des sols compressibles par des pieux est une solution très utilisée pour supporter les structures dans des zones sismiques. Plus récemment, la technique de renforcement par inclusions rigides a été utilisée. La différence entre les deux techniques réside dans le fait que, dans la technique du renforcement par inclusions rigides, un matelas de transfert de charge est intercalé entre la structure et les têtes des inclusions rigides. L’utilisation du matelas permet la dissipation d’énergie liée au séisme.Ce travail de thèse étudie le comportement sismique des sols compressibles renforcés par des pieux (système sol-pieux-structure) et des inclusions rigides (système sol-inclusions-matelas-structure). L’étude est effectuée à l’aide d’une modélisation numérique tridimensionnelle par différences finies avec le code Flac3D. Plusieurs types de sol ont été considérés en prenant en compte des états drainés et non drainés. Pour les cas non drainés, les analyses ont été réalisées à l'aide de simulations hydro-mécaniques couplées. Des modèles constitutifs simples et complexes ont été utilisés pour représenter le comportement du sol. Un amortissement de type Rayleigh a été appliqué pour fournir un amortissement supplémentaire à la partie élastique lorsque des modèles constitutifs élastoplastiques simples ont été considérés.L’objectif de ce travail est d’identifier l’impact des facteurs importants sur la réponse des systèmes analysés. Des nombreux paramètres comme le type de fondation, la fréquence du chargement, les caractéristiques dynamiques de la structure, le profil de sol et la densité relative ont été étudiés. En tenant compte des fondations sur pieux et des inclusions rigides, les conditions aux extrémités des pieux, la configuration du groupe de pieux, la longueur des pieux et l'encastrement des fondations ont également été investigués.Des aspects importants relatifs aux modèles numériques ont également été explorés tels que la géométrie du modèle, les frontières absorbantes, la taille des éléments du maillage, les éléments d'interface, les éléments structurels et le chargement dynamique.Les mouvements et contraintes dans le sol, les structures et les éléments rigides de renforcement ont été analysés et ont permis de mettre en évidence l’influence des divers paramètres étudiés. Cette étude a permis de mettre en évidence l’influence de certains paramètres dans la réponse (accélérations, déplacements, efforts, contraintes, pression interstitielle) des systèmes évalués. Le type de rupture dans les éléments des systèmes étudiés ont également été mis en évidence.Mots-clés: pieux; inclusion rigide; modélisation numérique; analyse dynamique; interaction de la structure du sol; liquéfaction / A great amount of earthquakes have caused the collapse of important structures along the history. The design of earthquake-resistant structures depends greatly of the soil-structure interaction. This interaction implies the consideration of relative movements and load transfer mechanism simultaneously. Dealing with liquefiable soils the generation of pore pressure should also be considered.Pile system constitutes a common foundation of structures resting on soil layers of low stiffness and strength in seismic zones. More recently rigid inclusion systems were utilized. The difference is that in the rigid inclusion systems, the rigid elements are separated from the foundation slab by an earth platform that is able to transfer the surface loads and dissipate energy coming from the seismic loading.This manuscript studies the behavior, through numerical models, of inclusions systems (soil-inclusion-platform-structure) and pile systems (soil-pile-structure) considering soft soils under seismic loadings. Finite difference numerical models were developed using Flac3D. Several types of soils were utilized in drained and undrained conditions. For the undrained cases, the analyses were carrying out using dynamic coupled fluid-mechanical simulations with accuracy the behavior of soils. The Rayleigh damping approach was applied to provide additional damping in the elastic part when simple elasto-plastic constitutive models were considered.The objective of the investigation is the identification of the impact of important factors in the response of the analyzed systems. Factor such as the foundation type, the frequency of the input motion, the dynamic characteristics of the structure, the soil profile and the relative density were investigated. Considering the pile and rigid inclusion foundations, the support conditions, the pile group configuration, the pile length, the embedment of the foundation were also examined.Additional and important aspects of numerical model were also explored like the model geometry, dynamic boundary conditions, element size, interface elements, structural element types, dynamic loading.Results in terms of movements and stresses in the soil, superstructure and rigid elements were obtained. They show the great influence of some parameters in the response (accelerations, displacements, efforts, strains, pore pressure) of the evaluated systems. Others highlight the importance of a type of failure in the elements of the system.Keywords: pile; rigid inclusion; numerical modelling; dynamic analysis; soil structure interaction; liquefaction

O presente trabalho detalha o conceito de Projeto Interativo aplicado à obra de ampliação dos Molhes da Barra do Rio Grande-RS, uma das maiores obras de infraestrutura portuária do Brasil, a qual se desenvolve em substrato argiloso de baixa capacidade de suporte e elevada compressibilidade, com espessura média de 10m. A obra de ampliação dos molhes e sua estratigrafia são detalhados após a revisão de critérios de alerta aplicados à aterros sobre solos moles. Posteriormente com o intuito de aferir modelos, fez-se uma análise da sensibilidade dos parâmetros de projeto, através da aplicação dos conceitos de segurança segundo o Método dos Volumes Deslocados, a qual definiu que a relação de volumes deslocados (dVv/dVh - razão de volume vertical deslocado, dVv, por volume horizontal deslocado, dVh) é suscetível às condições de drenagem, aos parâmetros de resistência e compressibilidade do solo de fundação, da geometria da área carregada e dos locais onde as leituras são realizadas. A dependência das leituras a este conjunto de fatores reforça a necessidade de análises numéricas específicas para definição de níveis de alerta. A análise paramétrica observou também que a aferição de parâmetros deve ser feita distintamente entre parâmetros de resistência e compressibilidade. De posse destas observações foram aferidos os parâmetros de projeto. Sequencialmente fez-se a reavaliação das seções de simulação numérica através de uma retroanálise quando do alteamento dos molhes à cota +2m. Observou-se que as simulações conseguiram capturar o comportamento em campo, em termos de deslocamentos horizontais e verticais, distorções e poro pressão. Este procedimento foi repetido até a fase de fechamento dos molhes, retroanalisando-se etapas anteriores de construção para refinar a estimativa das etapas subsequentes, garantindo-se as condições de segurança da obra. Com base neste estudo apresenta-se uma discussão quanto à postulação de critérios de segurança em obras geotécnicas, observando que estes devem ser abrangentes, de acordo com as características da obra, definindo deformações máximas e controle de taxas de deformação e, em particular, a taxa de distorção que cresce linearmente próximo à ruptura e diminui quando do aumento da estabilidade durante o período de adensamento. / The concept of Interactive Design applied to a marine breakwater in Rio Grande-RS, southern Brazil, is described in the present paper. Besides a literature review concerning constructions control methods applied in soft soil embankments, the characteristics of the site and construction work are presented and, the stratigraphy is detailed, which is characterized by a soft foundation substrate of low capacity and high compressibility, with a thickness about 10m. Based on the need to postulate security levels in geotechnical projects, according the soft layer that support the current construction, the first steep was to perform a parametric evaluation of the breakwater using the Displaced Volume Method, a field stability control for embankments on soft soil. This parametric analyses shows that dVv/dVh (ratio of vertical volume displaced, dVv, per horizontal volume displaced, dVh) is a function of drainage conditions, strength and compressibility parameters, loaded area geometry, and location of measured points. The analysis is shown to be particularly sensitive to friction angle and compressibility .Given the sensitivity of the security analysis to several different parameters and geometrical conditions, it has been stressed that specific numerical analysis should be performed for every geotechnical problem. Using these observations, soil foundation parameters, obtained in the breakwater region, were checked, and recalibrated. After that, some back analysis to verify the models was made in all instrumentation sections. It was observed that the simulations were able to capture the measured behavior of horizontal and vertical displacements, distortions, and pore pressures. The analysis was repeated for different construction phases, so that a back-analysis of a previous stage could refine the predictions of the following stage. Finally, a field control is presented according to acceptable ranges of displacements, distortion and specially distortions rates, which increases linearly near the failure and decreases when increasing stability due to consolidation effects.

Num mundo obcecado pelas inovações e sedento pela velocidade, percebe-se a necessidade da constante busca por soluções em todas as áreas do conhecimento. Dentro da Geotecnia isso pode ser obtido com propostas geotécnicas que proporcionem custo reduzido, incluindo preservação dos recursos naturais. Promover o aproveitamento de solos que não apresentam características geotécnicas adequadas é um dos pontos observados nas pesquisas de inovações geotécnicas. Adequar o solo a características de resistência à compressão simples e valores de módulo de cisalhamento inicial, melhorando-o com o uso de cimentos já firmados no mercado nacional, e cimentos alternativos obtidos com a adição de resíduos é a linha que conduz esta pesquisa, que possui como objetivo principal verificar a influência da adição de cimentos em um solo mole orgânico do município de Porto Alegre – RS, Brasil. As misturas eram compostas por um único solo matriz e vários tipos de atente cimentante, sendo eles: cimento Portland CP V-ARI mais escória de alto forno moída (grossa); cimento Portland CP V-ARI mais escória de alto forno moída (fina); cimento Portland CP V-ARI mais fosfogesso (dihidratado); cimento Portland CP V-ARI mais fosfogesso (hemihidratado); cimento Portland CP V-ARI mais cal viva; e cimento Portland CP V-ARI. Os teores de tais agente cimentantes foram fixados em 75 kg/m³, 125 kg/m³, 175 kg/m³, 225 kg/m³ e 275 kg/m³, em massa de cimento por volume de solo, e com teor de umidade da mistura final determinado em 120%. Além da variação dos teores e do tipo de agente cimentante, também foram estipulados três tempos de cura 7, 28 e 90 dias. fim de avaliar qual mistura se comporta de maneira mais adequada, realizaram-se ensaios de resistência à compressão simples e medidas de módulo de cisalhamento inicial. Para que seja possível uma previsão de comportamento dessas misturas é proposta uma equação que leva em consideração a porosidade da mistura (h) e o teor volumétrico de agente cimentante (Civ), e também o fator de água/agente cimentante (a/c). Os resultados indicaram que o aumento no teor dos agentes cimentantes leva ao crescimento na resistência à compressão simples e também nos valores do módulo cisalhante inicial, para os três tempos de cura estudados. A tentativa de estabelecer uma metodologia de previsão de comportamento se apresentou de forma consistente através do método que leva em consideração a relação porosidade/teor volumétrico de agente cimentante e também pelo fator água/cimento (a/c), sendo que a resistência à compressão simples e os valores do módulo cisalhante inicial aumentam com o decréscimo do valores de “h/Civ” e “a/c”. A técnica de melhoramento do solo mole orgânico estudado se mostrou eficaz e capaz de ser realizada com vários tipos de agentes cimentantes, obtendo-se características distintas em função do tempo de cura, do teor e do tipo de agente cimentante adicionado ao solo. / In a world obsessed by innovation and thirsty for speed, it can be seen the need for constant search for solutions in all areas of knowledge. Within Geotechnical Engineering, it can be obtained with geotechnical proposals that provide reduced cost, including preservation of natural resources. Promoting the use of soils that do not have adequate geotechnical characteristics is one of the points observed in geotechnical research innovations. Adjusting the soil strength characteristics and initial shear modulus values, improving it with the use of standard cements and alternative cements obtained with the addition of waste is the line that leads this research, which has as main objective the verification of the influence of the addition of distinct binders in an organic soft soil of Porto Alegre - RS, Brazil. The mixtures were composed of a single soil matrix and various types of binders, namely: early strength Portland cement, early strength Portland cement mixed with ground furnace slag (coarse particles), early strength Portland cement mixed with ground furnace slag (fine particles), early strength Portland cement mixed with gypsum (di-hydrate), early strength Portland cement mixed with gypsum (hemi-hydrate) and early strength Portland cement mixed with quicklime. The binder amounts were set at 75 kg/m³, 125 kg/m³, 175 kg/m³, 225 kg/m³ and 275 kg/m³ in mass of binder per volume of soil, and moisture content of 120% regarding final mixture. In addition to changes in the amount and type of binders, three cure times were also stipulated 7, 28 and 90 days. In order to assess which mixture behaves more adequately, strength tests and initial shear modulus measures were carried out. In order to foreseen the mechanical behavior of the blends, a methodology that takes into account the porosity/volumetric cement content ratio ( /Civ), as well as the well-known water/cement ratio (a/c) are used. Results indicated that the increase in the binder content leads to an increase in compressive strength and also in the initial shear modulus, for all curing times. Both /Civ and a/c are capable to predict the unconfined compressive strength and the initial shear modulus. The studied technique of improving organic soft soils with various types of binders was successful, thus obtaining different characteristics in terms of curing time, binder content and type of binder added to the soil.

A estabilização de solos é uma técnica através da qual se busca a melhoria das características de comportamento do solo, especialmente em termos de resistência, deformabilidade, durabilidade e permeabilidade (Ingles & Metcalf, 1972). A ágil e rápida determinação do ganho de resistência de solos artificialmente cimentados ainda não é precisa, e necessita de grande aprimoramento. Com esse objetivo se desenvolveu um equipamento para previsão da resistência de solos moles orgânicos artificialmente cimentados que oferece rapidez nos ensaios e precisão nos resultados. O equipamento basicamente funciona com a cravação de uma haste com base circular alargada adaptada em um anel dinamométrico de nylon que penetra no solo e cujos resultados têm relação linear com a resistência à tração por compressão diametral e resistência à compressão simples independente do tipo de solo, adição de agente cimentante, tipo de agente cimentante, teor de umidade da mistura e tempo de cura. Neste estudo também são mostrados resultados do melhoramento de solo com diferentes teores de cimento e cal, bem como os efeitos dos teores de turfa e resíduo de folhas de eucalipto moídas. Além disso, são avaliados os efeitos do pH baixo através da acidificação das amostras com ácido clorídrico e sulfúrico. O teor de umidade do solo apresenta grande influência nos resultados, pois quanto maior a umidade menor a resistência ou maior o consumo de cimento. A adição de ácido húmico em teores de 0,5%, 2,1% e 4,0% apresentou redução de resistência à compressão simples. As misturas com resíduo de folha de eucalipto moídas e turfa apresentaram redução de resistência e também retardo na atuação dos agentes cimentantes. As misturas com adições de cimento atingiram de uma forma geral resultados superiores comparados com adições de cal virgem. No entanto a combinação de cimento e cal virgem apresentou ótimo desempenho até mesmo superior às misturas com adição de cimento. / Soil stabilization is a technique which seeks to improve the performance characteristics of the soil, especially in terms of strength, deformability, durability and permeability (Ingles & Metcalf, 1972). The agile and rapid determination of the resistance gain of artificially cemented soils is still not accurate and needs major improvement. The main objective of present research was the development and testing, as well as the correlation with standard equipments results, of an apparatus for predicting the resistance of artificially cemented organic soft soils in a fast and accurate testing procedure. The equipment developed in present research basically works with the penetration of a rod with a circular base (adapted in the tip of a dynamometer ring made of nylon) into cement treated soft soils whose results have linear relationship with the tensile strength and compression strength regardless of soil type, addition of cementing agent, type of cementing agent, moisture content of the mixture and curing time. In this study are also shown results of soil improvement due to insertion of different amounts of cement and/or lime, and the effects of the amounts of peat and crushed eucalyptus leaves into soil strength. Furthermore, the effects are evaluated from low pH by acidifying the sample with specific acids. The moisture content of the soil has a major influence on the results, the higher the humidity the lower resistance or higher cement consumption. The addition of humic acid at levels of 0.5%, 2.1% and 4.0% showed a reduction of the compressive strength. Mixtures with waste ground eucalyptus leaf and peat showed a delayed action on cementing agents. Some combinations of cements (cement, lime and ash) showed excellent performance. Combinations of cements generally obtained higher results compared to lime addition. However combinations of cement and lime came up with results better than mixtures with only cement.

O presente trabalho detalha o conceito de Projeto Interativo aplicado à obra de ampliação dos Molhes da Barra do Rio Grande-RS, uma das maiores obras de infraestrutura portuária do Brasil, a qual se desenvolve em substrato argiloso de baixa capacidade de suporte e elevada compressibilidade, com espessura média de 10m. A obra de ampliação dos molhes e sua estratigrafia são detalhados após a revisão de critérios de alerta aplicados à aterros sobre solos moles. Posteriormente com o intuito de aferir modelos, fez-se uma análise da sensibilidade dos parâmetros de projeto, através da aplicação dos conceitos de segurança segundo o Método dos Volumes Deslocados, a qual definiu que a relação de volumes deslocados (dVv/dVh - razão de volume vertical deslocado, dVv, por volume horizontal deslocado, dVh) é suscetível às condições de drenagem, aos parâmetros de resistência e compressibilidade do solo de fundação, da geometria da área carregada e dos locais onde as leituras são realizadas. A dependência das leituras a este conjunto de fatores reforça a necessidade de análises numéricas específicas para definição de níveis de alerta. A análise paramétrica observou também que a aferição de parâmetros deve ser feita distintamente entre parâmetros de resistência e compressibilidade. De posse destas observações foram aferidos os parâmetros de projeto. Sequencialmente fez-se a reavaliação das seções de simulação numérica através de uma retroanálise quando do alteamento dos molhes à cota +2m. Observou-se que as simulações conseguiram capturar o comportamento em campo, em termos de deslocamentos horizontais e verticais, distorções e poro pressão. Este procedimento foi repetido até a fase de fechamento dos molhes, retroanalisando-se etapas anteriores de construção para refinar a estimativa das etapas subsequentes, garantindo-se as condições de segurança da obra. Com base neste estudo apresenta-se uma discussão quanto à postulação de critérios de segurança em obras geotécnicas, observando que estes devem ser abrangentes, de acordo com as características da obra, definindo deformações máximas e controle de taxas de deformação e, em particular, a taxa de distorção que cresce linearmente próximo à ruptura e diminui quando do aumento da estabilidade durante o período de adensamento. / The concept of Interactive Design applied to a marine breakwater in Rio Grande-RS, southern Brazil, is described in the present paper. Besides a literature review concerning constructions control methods applied in soft soil embankments, the characteristics of the site and construction work are presented and, the stratigraphy is detailed, which is characterized by a soft foundation substrate of low capacity and high compressibility, with a thickness about 10m. Based on the need to postulate security levels in geotechnical projects, according the soft layer that support the current construction, the first steep was to perform a parametric evaluation of the breakwater using the Displaced Volume Method, a field stability control for embankments on soft soil. This parametric analyses shows that dVv/dVh (ratio of vertical volume displaced, dVv, per horizontal volume displaced, dVh) is a function of drainage conditions, strength and compressibility parameters, loaded area geometry, and location of measured points. The analysis is shown to be particularly sensitive to friction angle and compressibility .Given the sensitivity of the security analysis to several different parameters and geometrical conditions, it has been stressed that specific numerical analysis should be performed for every geotechnical problem. Using these observations, soil foundation parameters, obtained in the breakwater region, were checked, and recalibrated. After that, some back analysis to verify the models was made in all instrumentation sections. It was observed that the simulations were able to capture the measured behavior of horizontal and vertical displacements, distortions, and pore pressures. The analysis was repeated for different construction phases, so that a back-analysis of a previous stage could refine the predictions of the following stage. Finally, a field control is presented according to acceptable ranges of displacements, distortion and specially distortions rates, which increases linearly near the failure and decreases when increasing stability due to consolidation effects.