Littérature scientifique sur le sujet « Repeated load triaxial test »
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Articles de revues sur le sujet "Repeated load triaxial test"
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Puppala, Anand J., Aravinda M. Ramakrishna et Laureano R. Hoyos. « Resilient Moduli of Treated Clays from Repeated Load Triaxial Test ». Transportation Research Record : Journal of the Transportation Research Board 1821, no 1 (janvier 2003) : 68–74. http://dx.doi.org/10.3141/1821-08.
Texte intégralRésumé :
Three chemical stabilization methods—sulfate resistant cement (Type V), low-calcium fly-ash (Class F) mixed with sulfate resistant cement (Type V), and ground granulated blast furnace slag—were used in a series of repeated load triaxial tests on clayey soil to assess the effectiveness of these three stabilizers in enhancing resilient modulus ( MR) properties of the soil. MR results were measured from repeated load triaxial tests conducted on both control and treated soils at optimum moisture content levels. Test results were analyzed to understand the potentials of each stabilizer on MR response of the soils and to study the effects of confining and deviatoric stresses on resilient response of the treated soils. Mechanisms for MR enhancements in treated soils were developed, and a series of flexible pavement design exercises was conducted to evaluate the impact of each stabilizer on the design thickness of the asphalt surface layer of pavements.
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Lekarp, Fredrick, et Ulf Isacsson. « The Effects of Grading Scale on Repeated Load Triaxial Test Results ». International Journal of Pavement Engineering 2, no 2 (juillet 2001) : 85–101. http://dx.doi.org/10.1080/10298430108901719.
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Ji, Jie, Meng Chen, Zhi Suo, Jianming Wei, Jiani Wang et Lei Chen. « Rutting Prediction Model of Asphalt Mixture Based on the Triaxial Repeated Load Test ». Advances in Civil Engineering 2021 (24 juin 2021) : 1–9. http://dx.doi.org/10.1155/2021/5238680.
Texte intégralRésumé :
This study establishes a more reasonable and effective rutting prediction model called the quadratic modified Burgers rheological model by considering dynamic loads. Use ABAQUS to simulate the rutting depths through the existing Burgers model and the quadratic modified model and compare with the measured values of the multitemperature and load rutting tests and triaxial repeated load tests. The real tests were conducted on four asphalt mixtures, including SK-90 asphalt mixture, styrene-butadiene-styrene (SBS) modified asphalt mixture, direct coal liquefaction residue (DCLR) modified asphalt mixture, and compound DCLR modified asphalt mixture. The results showed that the range of error ratio and residual sum of squares between simulated and measured rutting depth based on the two different models are 5–35%/5.0–8.74% and 3–15%/0.9–3.1%, respectively, which show that the quadratic modified Burgers rheological model has a more accurate prediction.
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Puppala, Anand J., Suppakit Chomtid et Venkat Bhadriraju. « Using Repeated-Load Triaxial Tests to Evaluate Plastic Strain Potentials in Subgrade Soils ». Transportation Research Record : Journal of the Transportation Research Board 1913, no 1 (janvier 2005) : 86–98. http://dx.doi.org/10.1177/0361198105191300109.
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The design and the analysis of flexible pavement systems depend on soil layer characterization, traffic loads, and number of passes. The current AASHTO design method for flexible pavements uses resilient characteristics of subsoils to characterize and determine the structural support of each layer and to design the thickness of the layers. This moduli property, however, does not fully account for the plastic strain or rutting potentials of subsoils, as in the cases in which silt and mixed soils undergo high plastic deformations but possess high resilient properties. A study was initiated to establish a test procedure to use a repeated load triaxial device to measure plastic strain potentials of subgrade soils. Laboratory-compacted soil specimens were subjected to a repeated deviatoric load, determined as a percentage of static deviatoric load at failure under un-consolidated undrained conditions. The plastic strains were monitored during 10,000 repeated load cycles, and the accumulated plastic deformations were determined. The test procedure and test results conducted on two types of soils, a coarse sand and silty sand, are presented. Effects of soil type, compaction moisture content, dry unit weight, confining pressure, and deviatoric stresses on the plastic strains were addressed.
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Xue, Guoqiang, et Xiaoming Huang. « Research on Permanent Deformation of Asphalt Mixture by Triaxial Repeated Load Test ». Journal of Highway and Transportation Research and Development (English Edition) 5, no 1 (mars 2011) : 13–18. http://dx.doi.org/10.1061/jhtrcq.0000035.
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Hussain, Jawad, Douglas J. Wilson, Theunis F. P. Henning et David Alabaster. « Comparing Results between the Repeated Load Triaxial Test and Accelerated Pavement Test on Unbound Aggregate ». Journal of Materials in Civil Engineering 26, no 3 (mars 2014) : 476–83. http://dx.doi.org/10.1061/(asce)mt.1943-5533.0000822.
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Tutumluer, Erol, Navneet Garg et Marshall R. Thompson. « Granular Material Radial Deformation Measurements with a Circumferential Extensometer in Repeated Load Triaxial Testing ». Transportation Research Record : Journal of the Transportation Research Board 1614, no 1 (janvier 1998) : 61–69. http://dx.doi.org/10.3141/1614-08.
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Determination of both axial and radial specimen strains in a repeated load triaxial test is essential for properly characterizing the directional dependency of resilient granular material behavior. Radial deformation measurement is not yet included in the standard AASHTO test procedure. The method of measuring radial strains adopted in this study emphasizes the use of a contact-type specimen instrumentation technique with a circumferential chain extensometer. The circumferential extensometer was successfully used in repeated load triaxial testing to measure radial strains of three aggregate samples with different material types and properties. The accuracy of the measuring system was within 10−5 (in strains) when the smallest strains recorded were on the order of 10−4. Nonlinear stress-dependent models for properly characterizing the anisotropic granular material stiffnesses were developed from measured axial and radial strains. The vertical/horizontal stiffness ratios in the triaxial sample consistently increased with increasing principal stress ratios, which often occurs in pavements under wheel loading. In general, the repeatability in radial strain measurements was deemed to be satisfactory and more reliable strains were measured at low confining pressures.
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Zhao, Yu, Jie Liu et Hong Juan Wu. « The Experimental Study on Engineering Characteristics of Improved Clay ». Advanced Materials Research 463-464 (février 2012) : 169–74. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.169.
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The rapid transit railway foundation bed bears the repeated dynamic load of train besides the static-load from upper structure. The engineering characteristics of improved clay, in especial the dynamic performance under repeated dynamic load or train, is the key factors to determine the improved clay can be used as roadbed fill material. In this paper, the dynamic triaxial test is adopted to imitate the repeated load of train, and the engineering characteristics of improved clay is studied such as dynamic stress plastic strain and elastic strain etc. which influence the running seriously.
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Tutumluer, Erol, et Umit Seyhan. « Neural Network Modeling of Anisotropic Aggregate Behavior from Repeated Load Triaxial Tests ». Transportation Research Record : Journal of the Transportation Research Board 1615, no 1 (janvier 1998) : 86–93. http://dx.doi.org/10.3141/1615-12.
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Determining horizontal specimen response in a repeated load triaxial test is essential to properly characterize the directional dependency of unbound aggregate resilient behavior under anisotropic loading conditions. Recent research has applied artificial neural networks (ANNs) for predicting, in the absence of lateral deformation data, the anisotropic stiffness properties of granular materials from standard AASHTO tests. Feed-forward backpropagation-type neural networks were successfully trained with two triaxial stresses (confining pressure and applied deviator stress), measured vertical deformation, and two aggregate properties (compacted dry density and crushed particle percentage) used as input variables. The output variables were the horizontal and shear moduli for which the actual (target) values were derived and computed from test results. The ANN models predicted the two moduli, with mean errors of less than 3 percent compared with those computed by using experimental stresses and strains. Both the applied stress state and the aggregate properties were found to affect the generalization and thus the prediction ability of the ANN models.
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Qiao, Yaning, Andrew Dawson, Anders Huvstig et Leena Korkiala-Tanttu. « Calculating rutting of some thin flexible pavements from repeated load triaxial test data ». International Journal of Pavement Engineering 16, no 6 (22 août 2014) : 467–76. http://dx.doi.org/10.1080/10298436.2014.943127.
Texte intégralThèses sur le sujet "Repeated load triaxial test"
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Borges, RÃmulo Luiz. « Permanent deformation in asphalt mixtures from viscoplastic shift model and triaxial repeated load test ». Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13192.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoPermanent deformation or rutting is a major distress in asphalt pavements. To predict permanent deformation of asphalt mixtures the dynamic creep test is often used in laboratory, with the result presented in terms of the so called flow number. However, for this work it was performed the triaxial repeated permanent deformation load test, a confined test that better represents field conditions. The models that incorporate the flow number do not represent the main zone of the dynamic creep test result, denoted secondary region, in which the permanent deformation rate of growth is constant. In this work the Shift Model was used, which is a viscoplastic model that accesses the permanent deformation from the superposition principles, i.e., time-temperature superposition and time-stress superposition. Thus, the asphalt mixtures were tested under different loading conditions, temperature, load time and rest period, in order to assess three parameters of the test: parameter C, which indicates where the secondary region begins (parameter that governs the primary region of the test); the parameter α (alpha) is the slope of the secondary region; and the parameter B represents the level of permanent deformation of the secondary region. The results show that the TRLPD test is more severe than the conventional dynamic creep test. Nevertheless, the use of TRLPD test represents an advance in the understanding of the behavior of asphalt mixtures with respect to rutting performance, and has the advantage of allowing the use of results in computational simulations.
A deformaÃÃo permanente à um dos principais defeitos em pavimentos asfÃlticos. Para prever esta falha em revestimentos, por meio de ensaios laboratoriais, à frequentemente utilizado o ensaio de creep dinÃmico cujo resultado final à apresentado em termos do chamado flow number. No entanto, para este trabalho foi realizado o triaxial repeated load permanent deformation (TRLPD) test, que à um ensaio sob condiÃÃes de confinamento, a fim de melhor se aproximar das condiÃÃes encontradas em campo. Os modelos que incorporam o flow number nÃo representam a principal regiÃo de ensaio de creep dinÃmico, denominada regiÃo secundÃria, na qual o incremento de deformaÃÃo permanente cresce em valor constante. No presente trabalho utilizou-se o Shift Model, o qual à um modelo viscoplÃstico que avalia a deformaÃÃo permanente a partir da superposiÃÃo dos efeitos tempo-temperatura e tempo-tensÃo. Dessa forma, as misturas asfÃlticas foram testadas sob diferentes condiÃÃes de carregamento, temperatura, tempo de aplicaÃÃo de carga e perÃodo de repouso. Foram avaliados trÃs parÃmetros do ensaio em questÃo: o parÃmetro C, que fornece os dados de onde a regiÃo secundÃria se inicia (parÃmetro que governa a regiÃo primÃria do ensaio); o parÃmetro α (alfa), que à o aclive da regiÃo secundÃria; e o parÃmetro B, que representa o nÃvel de deformaÃÃo permanente da regiÃo secundÃria. Os resultados obtidos mostram que o ensaio TRLPD à mais severo do que o ensaio convencional de creep dinÃmico, porÃm considera-se que a utilizaÃÃo de ensaios confinados representa um avanÃo para o entendimento do comportamento das misturas asfÃlticas quanto à resistÃncia à deformaÃÃo permanente das mesmas, e este traz a vantagem de poder ser usado em simulaÃÃes computacionais.
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Zhalehjoo, Negin. « Characterisation of the deformation behaviour of unbound granular materials using repeated load triaxial testing ». Thesis, Federation University of Australia, 2018. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/166953.
Texte intégralRésumé :
Unbound Granular Materials (UGMs) are used in the base/subbase layers of flexible pavements for the majority of roads around the world. The deterioration of pavements increases with the increase of traffic loadings. To ensure the long-term performance and serviceability of pavement structures through a realistic design, the precise evaluation and comprehensive characterisation of the resilient and permanent deformation behaviour of pavement materials are essential. The present PhD study aims to investigate the characterisation of the resilient and permanent deformation behaviour of four road base UGMs sourced from quarries in Victoria, Australia, using Repeated Load Triaxial (RLT) testing. The triaxial system used in this study is instrumented with four axial deformation measurement transducers to achieve highly precise measurements and to evaluate the effect of instrumentation on the resilient modulus of UGMs. The resilient Poisson’s ratio of the studied UGMs is also determined using a radial Hall-Effect transducer. Moreover, a series of permanent deformation tests is performed to precisely characterise the axial and radial permanent deformation behaviour of UGMs and investigate the factors that may significantly influence the accumulated axial and radial permanent deformations. Finally, three permanent deformation models incorporated with a time-hardening procedure are employed to predict the magnitude of permanent strain for multiple stress levels of the RLT test. The predictions using the employed models are then compared against the measured values to evaluate the suitability of the models and to identify the model that best predicts the strain accumulation behaviour of the tested UGMs. While this study focuses on the resilient and permanent deformation behaviour of four Victorian UGMs under repeated loading, the knowledge generated from this comprehensive investigation will contribute towards the global development of more reliable methods for evaluating the long-term performance of pavement structures and minimising road maintenance and repair costs.Doctor of Philosophy
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Rahman, Mohammad Shafiqur. « Characterising the Deformation Behaviour of Unbound Granular Materials in Pavement Structures ». Doctoral thesis, KTH, Väg- och banteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-162277.
Texte intégralRésumé :
Unbound granular materials (UGMs) used in the base and sub-base layers of flexible pavements play a significant role in the overall performance of the structure. Proper understanding and characterization of the deformation behaviour of UGMs in pavement structures are, therefore, vital for the design and maintenance of flexible pavements. In this study, the resilient deformation (RD) and the permanent deformation (PD) behaviour of UGMs were investigated for the better understanding and improved modelling of these deformation characteristics. The study is based on a series of repeated-load triaxial (RLT) tests carried out on several UGMs commonly used in pavement structures. Here, the influences of stress level and moisture content - two of the most significant factors affecting the deformation behaviour of UGMs - were analysed. The effects of the grain size distribution and the degree of compaction were also considered. The study on the RD behaviour indicated that the resilient stiffness (MR)of UGMs increases with the increased bulk stress level, which can be satisfactorily described by the k-θ model. Moisture was found to negatively impact the MR as long as the deformation was mostly resilient with a negligible amount of accumulated PD. Analysis of the influence of moisture on the parameters k1 and k2 of the k-θ model showed that k1 decreases with increased moisture and k2 is relatively insensitive to moisture. Based on these observations, a simple model was developed for the impact of moisture on MR. The performance of this model was comparable to an existing moisture dependent MR model. In contrast, it was further observed that at the later stages of the RLT tests, after a relatively large number of load applications, the MR increased with increased moisture up to the optimum moisture content. This occurred when the RD was accompanied by a significant amount of PD. Further investigation suggested that moisture aided the post-compaction (PC) and possible particle rearrangement that resulted in the increased PD and increased MR. In this case k1 decreased, whereas k2 increased, with increased moisture. The existing MR-moisture model did not work for this behaviour. This suggests that the effect of PC on MRshould be considered in modelling. However, although not explored in this study, it may be possible to simulate this effect of increase in MR with increased moisture due to PC using the proposed model if k2 is expressed as a function of moisture. The PD characteristics of UGMs were investigated based on the multistage (MS) RLT test. In contrast with the single stage (SS) RLT test, the MS RLT test accounts for the effect of stress history and enables a comprehensive study of the material behaviour under cyclic stresses of various magnitudes. Since the existing PD models cannot be directly applied for the MS loading procedure, a general formulation based on the time hardening concept was derived that can be used to extend the models for the MS loading conditions. Based on this formulation, some of the current models were calibrated and their performance in predicting the PD behaviour in MS RLT tests was compared. The investigation regarding the impact of moisture on PD showed that moisture significantly increases the accumulation of PD. Generally, materials with finer grading showed more sensitivity to moisture with regards to both PD and RD. To characterize the impact of moisture, moisture sensitivity of different grain size distributions and the impact of the degree of compaction on PD with reduced effort, a simple model was proposed. Unlike some of the well-performing existing models, this model can be calibrated using a single MS RLT test without requiring any separate static failure triaxial tests. This model was validated using the MS RLT test data with satisfactory results. The sensitivity of the parameters of this model was studied with respect to moisture content, degree of compaction and grain size distribution. Some reasonable trends for the sensitivity of the parameters to these influential factors were obtained, which suggests that these may be further developed to incorporate into the model.QC 20150325
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Cunto, Flávio José Craveiro. « Determinação do módulo de resiliência através de ensaios triaxiais dinâmicos e a sua estimativa a partir de ensaios de compressão simples : estudo de três solos do nordeste brasileiro ». Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-28022018-142425/.
Texte intégralRésumé :
O módulo de resiliência é um parâmetro de crucial importância nas análises mecanísticas que envolvem a estimativa das tensões e deformações na estrutura do pavimento e no seu subleito, quando da ação do tráfego. Embora ensaios de campo possam ser empregados para se determinar o MR, a grande maioria das pesquisas nesse sentido são desenvolvidas em laboratório, onde é possível um maior controle das condições da amostra, dos sistemas de aplicação de carregamento e de medida dos deslocamentos. Entretanto, os ensaios em laboratório que visam à determinação do MR ainda são considerados especiais e exigem equipamentos relativamente complexos, ensejando portanto, pesquisas com a finalidade de se obter expressões que estimem o MR a partir de parâmetros advindos de ensaios mais simples e rotineiros. Neste trabalho foram realizados ensaios triaxiais dinâmicos para a determinação do módulo de resiliência de três solos empregados em rodovias do nordeste brasileiro. Através dos resultados de laboratório, verificou-se o desempenho dos modelos mais comumente empregados para se representar a variação do módulo de resiliência em função do estado de tensão. Observou-se para os três solos desta pesquisa, que o MR foi mais influenciado, quanto ao estado de tensão, pela tensão de confinamento e pela tensão principal maior. Analisou-se, por fim, a existência de uma expressão matemática entre o módulo de resiliência obtido a partir dos ensaios triaxiais dinâmicos e o módulo tangente inicial proveniente de ensaios de compressão simples, sob diversos níveis de tensão. Os resultados mostram que este tipo de associação é promissora, mas exige-se que o universo de solos estudados seja ampliado para que se estabeleça uma inferência decisiva.Resilient modulus is a crucial parameter in mechanistic analysis involving the estimation of stress and strains under the pavement structure subjected to traffic loading. While field tests can be used to determine the dynamic behavior of soils, most researches favor laboratory tests. Such preference is based on the fact that laboratory tests are less constrained because of their carefully controlled conditions. Unfortunately these tests are still unusual due to relative complex equipment, therefore researches involving the correlation of resilient modulus from repeated load triaxial tests with other test results is needed. In this work, repeated load triaxial tests were performed on three soils used in northeastern Brazilian roadways to estimate the resilient modulus. The performance of the models most commonly adopted to represent resilient modulus as a function of state of stress were verified. lt was observed for the three soils in this research, that confining stress and principal major stress influenced resilient moduli values. Predictive equations correlating the resilient modulus from repeated load triaxial tests and parameters from compressive strength tests, considering different states of stress were investigated. lt was shown that this type of empirical correlation presented satisfactory results, although incisive conclusions can\'t be drawn without a wider number and variety of soils.
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Carmo, Cássio Alberto Teoro do. « A avaliação do módulo de resiliência através de ensaios triaxiais dinâmicos de dois solos compactados e a sua estimativa a partir de ensaios rotineiros ». Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-14032018-111408/.
Texte intégralRésumé :
O conhecimento do módulo de resiliência dos materiais constituintes do pavimento e do seu subleito é indispensável quando o objetivo é projetá-lo, ou analisar o seu comportamento frente à solicitação das cargas rodoviárias. O módulo de resiliência é determinado, na maioria das vezes, a partir de resultados de ensaios triaxiais dinâmicos, que exigem equipamentos complexos para a sua realização. Assim, é desejável que se disponha de métodos que possibilitem a sua avaliação a partir de resultados de ensaios mais simples. Neste trabalho, foram realizados ensaios triaxiais dinâmicos para a determinação do módulo de resiliência de dois solos, um argiloso e outro arenoso fino, compactados nas energias normal e intermediária. A partir dos resultados dos ensaios cíclicos foi possível modelar a variação do módulo de resiliência com a variação do carregamento aplicado e identificar, entre as variáveis de tensão, aquelas que exercem maior influência no valor deste módulo. A existência de discrepâncias significativas entre os valores de módulo de resiliência obtidos a partir de sucessivos ensaios de um mesmo corpo-de-prova foi também investigada. Finalmente, analisou-se a existência de uma relação entre o módulo de resiliência obtido nos ensaios dinâmicos e o módulo tangente inicial proveniente de ensaios de compressão simples, sob diversos níveis de tensão. Os resultados mostram que este tipo de associação é promissora, mas exige-se que o universo dos solos estudados seja ampliado para que se estabeleça uma conclusão definitiva.The knowledge about the resilient modulus of the pavement constituent materials and subgrade is essential in order to design or to analyze theirs behavior subjected to traffic loading. Often, the resilient modulus is obtained from repeated load triaxial tests demanding complex equipment for their execution. Thus, is desirable to develop methods to permit its evaluation from more simple tests. In this work, repeated load triaxial tests are carried out to the determination of the resilient modulus of two soils, a clay and a fine sand, compacted in the normal and intermediate AASHTO compretion efforts. From the repeated load triaxial test data it was possible to model the variation of resilient modulus with the variation of applied loading as wellos to identify, among the stress parameters, those of more influence on the value of this modulus. The significant discrepancy among the resilient modulus values obtained from successive tests in the same sample was also investigated. Finally, equations were developed in order to correlata the resilient modulus from repeated load triaxial tests to parameters from compressive strength tests, considering different states of stress. lt was shown that this type of empirical correlation presented satisfactory results, although incisiva conclusions could not be drawn without using a lager number and variety of soils.
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Santos, Adriana Goulart dos. « Estudo do comportamento resiliente de três solos da região de Campo Grande-MS e de relações entre o módulo de resiliência e resultados de ensaios de compressão simples ». Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-06102009-093939/.
Texte intégralRésumé :
O conhecimento do módulo de resiliência (MR) é fundamental ao se projetar um pavimento, pois ele é necessário para o cálculo de tensões, deformações e deflexões nas suas camadas e subleito, bem como, a análise do desempenho do sistema. Embora ensaios de campo possam ser empregados para se determinar o MR, a grande maioria das pesquisas nesse sentido são desenvolvidas em laboratório, onde é possível um maior controle das condições da amostra, da aplicação de carregamento e medida dos deslocamentos. Porém, pela complexidade e alto custo dos ensaios de laboratório, há a necessidade de pesquisas que disponibilizem expressões que permitam estimar o MR a partir de resultados de ensaios mais simples que o triaxial cíclico e usuais na pavimentação. Nesta pesquisa, foram realizados ensaios triaxiais cíclicos para a determinação do MR de três solos empregados em rodovias de Campo Grande - MS. A partir dos resultados dos ensaios triaxiais cíclicos, verificou-se o desempenho dos modelos mais comumente empregados para se representar a variação do módulo de resiliência em função do estado de tensão. Foram propostas e analisadas expressões matemáticas entre o MR obtido a partir dos ensaios triaxiais cíclicos e o módulo tangente inicial proveniente de ensaios de compressão simples, sob diversos níveis de tensão. Finalmente, analisou-se a existência de relações que englobem, além dos solos estudados nesta pesquisa, os solos estudados anteriormente em outras pesquisas desenvolvidas na EESC-USP. Os resultados mostram que este tipo de associação é promissora, mas exige-se que o universo de solos estudados seja ampliado para que se estabeleça uma inferência decisiva.The resilient modulus knowledge (MR) is fundamental for pavement design, once it is necessary for stresses, strains and deflections calculus in its layers and subgrade, as well as, the analysis of system performance. Although field tests may be used to determine the dynamic behavior of soils, most of researchers favor laboratory tests, based on the fact that such tests are less constrained because of their carefully controlled conditions. Because laboratory procedures are considered complex and highly expensive, it is desirable to establish relationships among MR and other index properties that are relatively simple and usual in pavement construction. In this research, cyclic triaxial tests were performed to determine MR of three soils used in Campo Grande-MS roads. The performance of the models most commonly adopted to represent resilient modulus as a function of state of stress were verified. A mathematical expression among MR, obtained from the cyclic triaxial tests, and the initial tangent modulus, obtained from unconfined compression strength tests, were developed considering different states of stress. Finally, were analyzed the existence of relationships among soils studied in this research, and soils used in previous studies developed at EESC-USP. Results show that this type of empirical correlation presents a satisfactory results, however incisive conclusions cannot be taken without a large number and variety of soils.
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Gunasekara, Jayalath Chamara Prasad. « Performance of geogrid-reinforced unpaved pavements under cyclic loading ». Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/208419/1/Chamara%20Prasad_Gunasekara%20Jayalath_Thesis.pdf.
Texte intégralRésumé :
Composite geogrids can successfully be used as a pavement-reinforcement material to increase the performance of pavement structures. This thesis presents a comprehensive study that has investigated the effectiveness of composite geogrids as subgrade reinforcement in unpaved granular pavements that are subjected to cyclic loading and constructed with local materials available in Queensland, Australia. The research outcomes suggest guidelines to design and construct unpaved granular pavements with the composite geogrid reinforcement at the base-subgrade interface. These guidelines benefit the industry by reducing construction and maintenance costs, and environmental pollution.
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Zago, João Paulo. « Estudo da deformação permanente de três solos típicos de subleitos rodoviários de Santa Maria - RS ». Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/12036.
Texte intégralRésumé :
Studies conducted in 2016 show that 58% of the highways in Brazil presents any
deficiency in the pavement, signaling or in its geometry. These deficiencies are, on
average, the cause for about 6% of the accidents and for the increase of the
operational cust by 91,6%. Among them we can stress the permanent deformation,
the so called wheel tracks, which is harmful to the dynamic of the loads, to the
comfort provided by the pavement, increasing its risk. To the correct design of the
pavement it is very important to better know the characteristics of the materials to be
used. In this context, stands out the subgrade, the foundation for the whole structure
of the pavement, which one is studied in the present reseach by considering three
typical soils used as highway subgrade in Santa Maria, Rio Grande do Sul State, and
having the permanent deformations as the main focus. The metodology aplied in this
work consisted in the location, sampling and characterization of the soil fields, lab
tests and empirical machanistic design. Besides the physical, chemical and
mechanical characterizations, it was performed the repeated triaxial load test aiming
to obtain the resilient modulus and the permanent deformation parameters, according
to the Brazilian Petroleum Corporation Manual (PETROBRAS). The Resilient
Modulus model presented the better results with frequencies of 1 Hz and 2 Hz, and
the presence of silt in one of the soils affected its resilient behaviour. The permanent
deformation tests were performed with the frequency of 2 Hz and 150.000 load
cicles. The average statistic correlation, according to Guimaraes (2009)´s
methodology, was 0.91, bigger than the one provided by the Monismith and
Barksdale´s models. However, the dominance of fine grained soils, along with low
compactation energy, lead to a higher deformation rates, motivating the use of
intermediate energy. With this new approach the permanent deformation was
reduced 40% and the resilient modulus increased 78,8%. However, the numerical
simulation according to the mechanistic approach, and using the layer thickness
obtained from the Departamento Nacional de Infraestrutura de Transportes (DNIT)
method, under 8,2 ton standard axle load, showed that the wheel tracks deeping
would be small, based on the low stresses observed in the subgrade. On the other
hand, the fatigue behaviour presented an inferior performance, reducing the project´s
useful life. It was observed the presence of shakedown in the ranges A, B and C.Pesquisas realizadas no ano de 2016 mostram que 58,2 % das rodovias de todo o país apresentam alguma deficiência no pavimento, na sinalização ou na geometria da via. Em média, esses defeitos são responsáveis por cerca de 6% do número de acidentes, além de aumentar o custo operacional das vias em até 91,6%. Dentre essas anomalias, destaca-se a deformação permanente denominada de afundamento na trilha de roda (ATR), que prejudica a dinâmica das cargas, afeta o conforto ao rolamento e causa risco à segurança. Para o adequado dimensionamento de um pavimento, é fundamental o conhecimento dos materiais que o compõem. Neste contexto, destaca-se o subleito, por ser a fundação sobre a qual são assentes todas as camadas, motivo pelo qual o objetivo geral desta pesquisa é analisar três solos típicos de subleitos rodoviários de Santa Maria, estado do Rio Grande do Sul, em especial quanto aos parâmetros de deformação permanente. A metodologia aplicada neste trabalho consistiu na localização, coleta e caracterização das jazidas de solos, realização de ensaios laboratoriais e dimensionamento mecanístico - empírico. Assim, além da caracterização física, química e mecânica, foram realizados ensaios triaxiais de cargas repetidas para obtenção do módulo de resiliência e dos parâmetros de deformação permanente, segundo recomendações do manual de execução de trechos monitorados da empresa Petróleo Brasileiro Sociedade Anônima (PETROBRAS). O modelo composto do módulo de resiliência apresentou os melhores resultados, a partir de ensaios com frequência de 1 Hz e 2 Hz, sendo que a presença de silte em um dos solos afetou seu comportamento resiliente. Os ensaios de deformação permanente foram conduzidos a 2 Hz, com 150.000 ciclos de aplicação de carga, cuja correlação estatística média, empregando a metodologia de Guimarães (2009), foi de 0,91 – superior a dos modelos de Monismith e Barksdale. Entretanto, a predominância de materiais finos, aliada à baixa energia de compactação (normal), resultaram em elevadas taxas de deformação, o que motivou o estudo de um dos solos também com uso da energia intermediária. Esse procedimento reduziu a deformação permanente em 40% e elevou o módulo de resiliência em 78,8%. Entretanto, a simulação numérica do pavimento sob a ótica mecanicista, a partir das espessuras calculadas pelo método do Departamento Nacional de Infraestrutura de Transportes (DNIT), aplicando-se a carga padrão de 8,2 toneladas, mostrou que o ATR seria pequeno, em face das baixas tensões atuantes no subleito, em contraposição ao desempenho à fadiga, que reduziu sensivelmente a vida útil de projeto. Constatouse a ocorrência de shakedown nos domínios A, B e C.
9
Ho, Xuan Nam. « Comportement hydromécanique des matériaux granulaires compactés non saturés ». Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAD032/document.
Texte intégralRésumé :
Les matériaux granulaires sont souvent utilisés les chaussées à faible et moyen trafic, pour la réalisation des couches d’assise, des couches de forme et de la couche de sol support. Les sollicitations dues au trafic sont les principales causes d’endommagement de ces chaussées qui conduisent à deux modes de dégradation: l’orniérage à grand rayon et la fissuration par fatigue de la couverture bitumineuse. L’influence de la non saturation et de la teneur en fines sur la capacité portante des sols granulaires joue un rôle très important sur la rigidité mécanique ainsi que l’endommagement des structures de chaussées soumises aux chargements répétés du trafic. En plus, le phénomène d’hystérésis produit par les conditions environnementales, notamment les conditions hydriques a également une influence importante sur la rigidité de ces matériaux non liés. Cependant, la méthode de dimensionnement des chaussées neuves en France ne permet pas de prendre en compte correctement l’effet de teneur en fines et l’effet de l’hystérésis hydrique. L’objectif de la thèse est d’étudier l’effet de la non-saturation, de la teneur en fines et de l’hystérésis hydrique sur le comportement mécanique des matériaux granulaires de chaussées soumis aux chargements répétés du trafic. Nous avons réalisé une campagne d’essais à différentes teneurs en eau sur deux chemins d’humidification et de séchage, avec mesure de la succion, de la résistance au cisaillement et du comportement résilient (essais triaxiaux à chargements répétés). Finalement, à l’aide de ces résultats expérimentaux, nous avons déterminé les paramètres des modèles classiques d’élasticité non linéaire. Ces modèles sont implantés dans le code de calcul aux éléments finis CAST3M pour déterminer la déflexion de chaussées souples lorsqu’elles sont soumises à des sollicitations mécaniques de trafic et des sollicitations hydriques environnementalesGranular materials are often used in low traffic pavement structures, with unbound granular base and sub-base layers. The load due to traffic is one of the principal damage modes for these pavements. The main design criteria for these pavements are a rutting criterion for the subgrade, a fatigue criterion for the asphalt layer. The variation of the unsaturated state and the clay content in granular materials have a significant influence on their mechanical behavior. In addition, the hysteresis phenomenon produced by the environmental conditions, including water conditions also has a very important influence on the rigidity of the unbound material. Whereas, the French design method is based on linear elastic calculations. It does not take into account theinfluence of clay content of pavement materials and the influence of the hysteresis phenomenon. Then, the objective of this thesis is to study the unsaturated state, the clay content and the hysteresis phenomenon on mechanical behavior of unbound granular materials for roads subjected to traffic loading. A series of tests for different water contents on both wetting and drying paths have been carried out with matrix suction measurements, shear tests and repeated load triaxial tests for the resilient behavior. Finally, the experimental results were simulated using the nonlinear elastic model (modified Boyce model) generally used for the resilient behavior of granular soils. These models are implemented in the finite element code and calculations have been performed with CAST3M to determine the deflection of full scale pavements at different environmental conditions
10
Salour, Farhad. « Moisture Influence on Structural Behaviour of Pavements : Field and Laboratory Investigations ». Doctoral thesis, KTH, Väg- och banteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-162076.
Texte intégralRésumé :
The structural behaviour of pavements in cold regions can considerably be affected by seasonal variation in environmental factors such as temperature and moisture content. Along with the destructive effect of heavy traffic loads, climatic and environmental factors can considerably contribute to pavement deterioration. These factors can influence the structural and functional capacity of the pavement structures which, as a result, can trigger and accelerate pavement deterioration mechanisms. Studies on the influence of variation of the environmental factors on the response and behaviour of pavement materials have shown that proper consideration to these factors must be given in realistic pavement design and analysis. In flexible pavement structures, particularly with a thin hot mix asphalt (HMA) layer, unbound materials and subgrade soil largely contribute to the overall structural behaviour of the pavement system. In unbound materials, moisture content and its variation can significantly affect pavement layer stiffness and permanent deformation characteristics. Therefore, the moisture condition of pavements and its influence on the mechanical behaviour of pavement materials has been of interest among the pavement research community. A proper understanding of moisture transformation in pavement systems and its effects on pavement performance are important for mechanistic pavement design. The present summary of this doctoral thesis is based on four main parts. The first part of the thesis covers field measurements and findings from a test section along county road 126 in southern Sweden and consists of two journal papers (paper I and II) tackling different aspects of the research topic. This test section is located in a relatively wet ground condition and consists of a thin flexible pavement structure with a deep drainage system. It is instrumented with subsurface temperature, volumetric moisture content and groundwater probes. The mechanical response of the pavement structure was investigated using Falling Weight Deflectometer (FWD) measurements. The second part of the thesis (paper III and IV) are based on laboratory experiments and investigates different recent approaches that have been proposed to apply principles of unsaturated soil mechanics for incorporating seasonal variation of moisture content into the resilient modulus models using matric suction. The third part of the thesis (paper V) builds a bridge that spans between the laboratory and field investigations with an attempt to evaluate one of the predictive models presented in Paper III. The fourth part of the thesis (paper VI) mainly focuses on the laboratory-based investigation of the permanent deformation characteristic of subgrade soils. In this part, the permanent deformation characteristics of two different silty sand subgrade soils were investigated and modelled using the data obtained from repeated load traxial tests. Paper I mainly focuses on the spring-thaw weakening of the pavement structure. The environmental data collected using different sensors and the FWD tests were used to investigate variations in moisture content with thaw penetration and its influence on the stiffness of unbound layers and the pavement’s overall bearing capacity. Using the backcalculated layer stiffness and corresponding in situ moisture measurements in the unbound layers, a degree of saturation-based moisture-stiffness model was developed for the granular material and the subgrade. In Paper II, the drainage system of the structure was manually clogged during a three month period in summer to raise the groundwater level and increase the moisture content of the layers. Along with the subsurface groundwater level and moisture content monitoring, the structural response of the pavement was studied. In this research work, the FWD tests were conducted at three different load levels. The stress dependent behaviour of the unbound granular layer and the subgrade soil were further studied using the multilevel loads FWD test data. Additionally, parameters of a nonlinear stress-dependent stiffness model were backcalculated and their sensitivity to in situ moisture content was studied. In Paper III and IV, series of suction-controlled repeated load triaxial (RLT) tests were conducted on two silty sand (SM) subgrade materials. Several resilient modulus prediction models that account for seasonal moisture content variation through matric suction were summarized and after optimizing the model parameters, the capability of the prediction models in capturing the material response were evaluated. In Paper V, an attempt was made to evaluate the proficiency of one of the suction-resilient modulus models using the field moisture content and FWD measurements from the Torpsbruk test site. The backcalculated subgrade stiffness dataset at different moisture contents were compared with resilient modulus models obtained from the suction-resilient modulus predictive model. Paper VI presents an evaluation of several permanent deformation models for unbound pavement materials that incorporate the time-hardening concept using a series of multistage repeated load triaxial (RLT) tests conducted on silty sand subgrade materials. The permanent deformation tests were conducted at four different moisture contents with pore suctions measurement throughout the test. The effect of moisture content (matric suction) on the permanent deformation characteristics of the materials and the predictive model parameters were further investigated.QC 20150324
Chapitres de livres sur le sujet "Repeated load triaxial test"
1
Frost, M. W., P. R. Fleming et C. D. F. Rogers. « Threshold Stress and Asymptotic Stiffness of UK Clays in the Repeated Load Triaxial Test ». Dans Bearing Capacity of Roads, Railways and Airfields, 1099–108. CRC Press, 2020. http://dx.doi.org/10.1201/9781003078821-31.
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2
Yang, Yong, Jianping Zhu et Haonan Ding. « Effect of Maximum Particle Size on Resilient Modulus of Unbound Granule Materials by Repeated Load Triaxial Test ». Dans Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220427.
Texte intégralRésumé :
The unbound granule material (UGM) is widely applied as the base/subbase layer in pavement engineering. The poor quality of UGMs mainly result in differential settlement and fatigue failure of UGMs. This paper presents a laboratory investigation on the influence of the maximum particle size (MPS) of aggregates on the resilient modulus (MR) of UGMs. The repeated load triaxial tests were performed under different stress levels. Three nonlinear models were compared to describe the mechanical behavior of UGMs. The results show that the particle size plays a significant role in the MR of UGMs. When the MPS of UGMs increases from 19mm to 26.5mm, its dynamic MR increases by 6.8% on average. When the particle size increases from 26.5mm to 31.5mm, the dynamic MR increases by 13.3% on average. Meanwhile, the MR is also dependent on the deviatory stress and the confining pressure. The N37A model has a better goodness of fit than the others. In a word, it effects of the MPS should be taken into account in the pavement design, to make sure that the loading and deformation of pavement structure more uniform.
3
Brown, S. F., M. P. O'Reilly et J. W. Pappin. « A repeated load triaxial apparatus for granular materials ». Dans Unbound Aggregates in Roads, 143–58. Elsevier, 1989. http://dx.doi.org/10.1016/b978-0-408-04355-7.50025-x.
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4
Zhalehjoo, N., A. Tolooiyan, R. Mackay et D. Bodin. « Characterisation of permanent deformation behaviour of unbound granular materials using repeated load triaxial testing ». Dans Bearing Capacity of Roads, Railways and Airfields, 159–66. CRC Press, 2017. http://dx.doi.org/10.1201/9781315100333-21.
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5
Sparsha, Nagula, R. G. Robinson et J. Murali Krishnan. « Use of repeated load CBR test to characterize pavement granular materials ». Dans Functional Pavement Design, 965–74. CRC Press, 2016. http://dx.doi.org/10.1201/9781315643274-105.
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6
Salmi, Abdelaziz, Lahbib Bousshine et Khaled Lahlou. « Study on Two Unbound Granular Materials Stiffness Analysis with Staged Repeated Load CBR Test ». Dans Advanced Aspects of Engineering Research Vol. 1, 142–48. Book Publisher International (a part of SCIENCEDOMAIN International), 2021. http://dx.doi.org/10.9734/bpi/aaer/v1/7098d.
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7
« Rut depth prediction of granular pavements using the repeated load triaxial apparatus and application in New Zealand specifications for granular materials ». Dans Advances in Transportation Geotechnics, 79–86. CRC Press, 2008. http://dx.doi.org/10.1201/9780203885949-12.
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Ellis, J., D. Robinson, S.Werkmeister, A. Dawson, D. Arnold, J. Lowe, D. Hughes, D. Alabaster, R. Ashby et G. Arnold. « Rut depth prediction of granular pavements using the repeated load triaxial apparatus and application in New Zealand specifications for granular materials ». Dans Advances in Transportation Geotechnics, 65–71. CRC Press, 2008. http://dx.doi.org/10.1201/9780203885949.ch7.
Texte intégralActes de conférences sur le sujet "Repeated load triaxial test"
1
Puppala, Anand J., Suppakit Chomtid et Ekarin Wattanasanticharoen. « Plastic Deformation Potentials of Sandy Clay from Repeated Load Triaxial Test ». Dans GeoTrans 2004. Reston, VA : American Society of Civil Engineers, 2004. http://dx.doi.org/10.1061/40744(154)81.
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2
Nazzal, Munir D., Murad Abu-Farsakh et Louay N. Mohammad. « Evaluation of Geogrid Benefits Using Monotonic and Repeated Load Triaxial Tests ». Dans Geo-Denver 2007. Reston, VA : American Society of Civil Engineers, 2007. http://dx.doi.org/10.1061/40924(308)12.
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3
Rahman, Md Mostaqur, et Sarah L. Gassman. « Permanent Deformation Characteristics of Coarse Grained Subgrade Soils Using Repeated Load Triaxial Tests ». Dans Eighth International Conference on Case Histories in Geotechnical Engineering. Reston, VA : American Society of Civil Engineers, 2019. http://dx.doi.org/10.1061/9780784482124.061.
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4
Qian, Yu, Erol Tutumluer, Youssef M. A. Hashash et Jamshid Ghaboussi. « Effects of Ballast Degradation on Permanent Deformation Behavior From Large-Scale Triaxial Tests ». Dans 2014 Joint Rail Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/jrc2014-3806.
Texte intégralRésumé :
Consisting of large sized aggregate particles with uniform size distribution, ballast is an essential component of the track substructure to facilitate load distribution and drainage. As freight tonnage accumulates with traffic, ballast will get fouled increasingly due to either aggregate breakdown and degradation or contamination by other materials such as coal dust and subgrade soil intrusion. Fouling affects shear strength and load carrying ability of ballast layer especially under wet conditions. According to Selig and Waters [1], ballast fouling is often due to aggregate degradation, which covers up to 76% of all the fouling cases. To investigate the effects of ballast aggregate breakdown and degradation on the mechanical behavior of fouled ballast, a series of Los Angeles abrasion tests were performed in this study to generate fouled ballast materials caused by particle breakage and abrasion under a well-controlled laboratory environment. The change of particle shape properties during the Los Angeles abrasion tests was quantified and studied through image analysis technology. Large-scale triaxial tests were performed on specimens of new ballast, degraded ballast coarse particle fraction (without fines), and full gradation of degraded ballast (with fines) under repeated load application using a triaxial test device recently developed at the University of Illinois specifically for ballast size aggregate materials. The large-scale triaxial results indicated that the specimen having those degraded coarse particles yielded higher permanent deformation trends from repeated load triaxial testing when compared to the specimen with the new ballast gradation. As expected, the highest permanent deformation was obtained from the degraded ballast specimen having fine particles and the Fouling Index (FI) value of approximately 40.
5
Sobhan, Khaled, D. V. Reddy et Michael J. Genduso. « Permanent Strain Characterization in Granular Materials Using Repeated Load Triaxial Tests and Digital Image Correlation (DIC) Technique ». Dans GeoCongress 2008. Reston, VA : American Society of Civil Engineers, 2008. http://dx.doi.org/10.1061/40972(311)23.
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Qian, Yu, Debakanta Mishra, Erol Tutumluer, Youssef M. A. Hashash et Jamshid Ghaboussi. « Moisture Effects on Degraded Ballast Shear Strength Behavior ». Dans 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5840.
Texte intégralRésumé :
Ballast consisting of large sized aggregate particles with uniform size distribution is an essential component of the track substructure, to facilitate load distribution and drainage. As freight tonnage accumulates with traffic, ballast will accumulate an increasing percentage of fines due to either aggregate breakdown or outside contamination such as subgrade soil intrusion and coal dust collection. According to the classical text by Selig and Waters [1], ballast degradation from traffic involves up to 76% of all fouling cases; voids will be occupied by fines from the bottom of ballast layer gradually causing ballast clogging and losing its drainage ability. When moisture is trapped within ballast, especially fouled ballast, ballast layer stability is compromised. In the recent studies at the University of Illinois, the focus has been to evaluate behavior of fouled ballast due to aggregate degradation using large scale triaxial testing. To investigate the effects of moisture on degraded ballast, fouled ballast was generated in the laboratory through controlled Los Angeles (LA) abrasion tests intended to mimic aggregate abrasion and breakdown and generate fouled ballast at compositions similar to those observed in the field due to repeated train loadings. Triaxial shear strength tests were performed on the fouled ballast at different moisture contents. Important findings of this preliminary study on characterizing wet fouled ballast are presented in this paper. Moisture was found to have a significant effect on the fouled ballast strength behavior. Adding a small amount of 3% moisture (by weight of particles smaller than 3/8 in. size or smaller than 9.5 mm) caused test specimens to indicate approximately 50% decrease in shear strength of the dry fouled ballast. Wet fouled ballast samples peaked at significantly lower maximum deviator stress values at relatively smaller axial strains and remained at these low levels as the axial strain was increased.
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Xiao, Jun-hua, et Yan-bin Guan. « Resilient Behavior of Compacted Silt under the Repeated Triaxial Test ». Dans Tenth International Conference of Chinese Transportation Professionals (ICCTP). Reston, VA : American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41127(382)324.
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Araya, Alemgena, Andre Molenaar et Lambert Houben. « Characterization of Unbound Granular Materials Using Repeated Load CBR and Triaxial Testing ». Dans GeoShanghai International Conference 2010. Reston, VA : American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41104(377)44.
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Kang, Mingu, Han Wang, Issam I. A. Qamhia et Erol Tutumluer. « Modulus Properties of Granular Materials at Various Strain Levels from Repeated Load Triaxial Testing with Bender Elements ». Dans Geo-Congress 2022. Reston, VA : American Society of Civil Engineers, 2022. http://dx.doi.org/10.1061/9780784484067.042.
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Pi, Yuhui, et Xiaoming Huang. « Research on Permanent Deformation of an Asphalt Mixture by Uniaxial Repeated Load Test ». Dans Tenth International Conference of Chinese Transportation Professionals (ICCTP). Reston, VA : American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41127(382)378.
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