Dissertations / Theses on the topic 'Soil Stress'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Soil Stress.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Parathiras, Vasilis. "Stress-density relationships for an agricultural soil." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/40978.
Full textTriaxial tests under high loading rates and different confining pressures simulate the multi-pass effect of a tractor wheel loading on the soil. A volume measuring technique was developed to be used in triaxial tests conducted under high loading rates.
A sandy clay agricultural soil was tested under predetermined conditions using an INSTRON loading frame, a differential pressure transducer and an APPLE Il + microcomputer. A preliminary analysis indicated that the measuring technique that was developed, was capable of recording volume changes under high loading rates. Stress-density plots were created using the obtained data and a mathematical model was developed relating stress to density. Stress-strain data was used to evaluate the soil parameters under the Mohr-Coulomb failure criteria. Furthermore, the influence of the initial soil density on the soil behavior was evaluated and subsequently compared to the results of a similar study conducted under a different initial density.
Master of Science
Bones, Emma Jean. "Predicting critical shear stress and soil erodibility classes using soil properties." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52198.
Full textDu, Plessis Keith R. (Keith Roland). "Biological indicators of copper-induced stress in soil." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52719.
Full textENGLISH ABSTRACT: The concentrations of copper (Cu) in vineyard soils of the Western Cape range from 0.1 to 20 ppm. However, more than 160 tons of the fungicide copper oxychloride are annually being sprayed on these vineyards. This has raised concerns that Cu may accumulate in these soils, resulting in a negative impact on the soil biological processes, especially since the soils in the Western Cape are slightly acidic, making Cu more mobile and available for soil organisms than would have been the case in alkaline soils. The goal of the initial part of this study was therefore to identify those soil microbial communities indigenous to the Western Cape, which are most susceptible to Cu-induced stress as a result of the addition of copper oxychloride. These potential bioindicators of Cu-induced stress were first searched for in uncultivated agricultural soil from Nietvoorbij experimental farm. Consequently, a series of soil microcosms was prepared by adding various concentrations of Cu as a component of copper oxychloride, to each of eight aliquots of soil: 0 (control), 10, 20, 30, 40, 50, 100, 500 and 1000 ppm. The resulting concentrations of exchangeable Cu in these microcosms were found to be 2 (control), 12,23,34,42,59, 126,516 and 1112 ppm. Selected microbial communities in each microcosm were subsequently monitored over a period of 245 days. It was found that the culturable microbial numbers did not provide a reliable indication of the effect of Cu on community integrity. However, analyses of terminal-restriction fragment length polymorphism (T-RFLP) community fingerprints and especially analyses of the whole community metabolic profiles, revealed that shifts in the soil microbial communities took place as the Cu concentration increased. Direct counts of soil protozoa also revealed that the addition of Cu to the soil impacted negatively on the numbers of these eukaryotes. To confirm these findings in other soil ecosystems, the impact of copper oxychloride on whole community metabolic profiles and protozoan numbers were investigated in soils from Koopmanskloof commercial farm and Nietvoorbij experimental farm. These potential bioindicators were subsequently monitored in a series of soil microcosms prepared for each soil type by adding the estimated amounts of 0 (control), 30, 100 and 1000 ppm Cu as a component of copper oxychloride to the soil. The results confirmed the fmdings that elevated levels of copper impact negatively on the metabolic potential and protozoan numbers of soil. Consequently, it was decided to investigate a combination of protozoan counts and metabolic profiling as a potential bioindicator for Cu-induced stress in soil. Data collected from all the microcosms containing exchangeable Cu concentrations ranging from 1 ppm to 1112 ppm was used to construct a dendrogram using carbon source utilization profiles in combination with protozoan counts. It was found that the microcosms grouped into clusters, which correlated with the concentration of exchangeable Cu in the soil. Under the experimental conditions used in this study, the combination of protozoan counts and metabolic profiling seemed to be a reliable indicator of Cu-induced stress. However, this bioindicator must be further investigated in other soil types using other types of stress inducing pollutants. In addition to the above fmdings it was also found that the numbers of soil protozoa was particularly susceptible to Cu-induced stress in soils with a low soil pH. This is in agreement with the fmdings of others on the bio-availability of heavy metals in low pH soils. In these soils, nutrient cycling as a result of protozoan activity, may therefore be particularly susceptible to the negative impact of copper to the soil.
AFRIKAANSE OPSOMMING: Die konsentrasies van koper (Cu) in wingerdgronde van die Wes-Kaap wissel tussen 0.1 en 20 dpm. Meer as 160 ton van die fungisied koper-oksichloried word egter jaarliks op dié wingerde gespuit, wat kommer laat ontstaan het oor die moontlike akkumulasie van Cu in dié grond en die gevaar van 'n negatiewe impak op die biologiese prosesse in die grond. Die gevaar word vererger deur die feit dat die Wes-Kaapse grond effens suur is, wat Cu meer mobiel en beskikbaar maak vir grondorganismes as wat die geval sou wees in alkaliese grond. Die eerste doelstelling van hierdie studie was dus om die mikrobiese gemeenskappe in die grond, wat inheems is aan die Wes-Kaap, te identifiseer wat die meeste vatbaar is vir Cu-geïnduseerde stres as gevolg van die toevoeging van koper-oksichloried. Hierdie potensiële bioindikatore van Cu-geïnduseerde stres is eerstens gesoek in onbewerkte landbougrond van die Nietvoorbij-proefplaas. 'n Reeks grondmikrokosmosse is gevolglik berei deur verskillende konsentrasies Cu, as 'n komponent van koperoksichloried, by elk van agt hoeveelhede grond te voeg naamlik 0 (kontrole), 10,20, 30, 40, 50, 100, 500 en 1000 dpm. Die gevolglike konsentrasies van uitruilbare Cu in hierdie mikrokosmosse was 2 (kontrole), 12, 23, 34, 42, 59, 126, 516 en 1112 dpm. Geselekteerde mikrobiese gemeenskappe in elke mikrokosmos is vervolgens oor 'n tydperk van 245 dae bestudeer. Daar is gevind dat die kweekbare mikrobiese tellings nie 'n betroubare aanduiding kon gee van die uitwerking van Cu op gemeenskapsintegriteit nie. Die ontledings van terminale-restriksie fragment lengte polymorfisme (T-RFLP) gemeenskapsvingerafdrukke en veral van die metaboliese profiele van die totale gemeenskap, het getoon dat verskuiwings in die grondmikrobiese gemeenskappe plaasgevind het met 'n toename in Cu-konsentrasies. Direkte tellings van grondprotosoë het ook aangedui dat die toevoeging van Cu tot die grond 'n negatiewe uitwerking op die getalle van hierdie eukariote gehad het. Om dié resultate te bevestig, is die impak van koper-oksichloried op die metaboliese profiele van totale gemeenskappe en protosoë-getalle in ander grond-ekosisteme vervolgens bestudeer deur grond van die kommersiële plaas Koopmanskloof en die Nietvoorbij-proefplaas te gebruik. Dié potensiële bioindikatore is vervolgens bestudeer in 'n reeks grondmikrokosmosse, wat vir elke grondtipe voorberei is deur die toevoeging van beraamde hoeveelhede van 0 (kontrole), 30, 100 en 1000 dpm Cu as 'n komponent van koper-oksichloried. Die resultate het die bevindings bevestig dat verhoogde vlakke van Cu 'n negatiewe uitwerking het op die metaboliese potensiaal en op die protosoëgetalle in die grond. Daar is gevolglik besluit om 'n kombinasie van protosoë-tellings en metaboliese profiele te ondersoek as 'n potensiële bioindikator van Cu-geïnduseerde stres in grond. Data van al die mikrokosmosse wat uitruilbare Cu bevat, wisselend van 1 dpm tot 1112 dpm, is gebruik om 'n dendrogram te konstrueer wat koolstofbronbenuttingsprofiele in kombinasie met protosoë tellings gebruik. Daar is gevind dat die mikrokosmosse groepe vorm wat korrelleer met die konsentrasie uitruilbare Cu in die grond. Onder die eksperimentele kondisies wat in dié studie gebruik is, wil dit voorkom of die kombinasie van protosoë-tellings en metaboliese profiele 'n betroubare indikator van Cugeïnduseerde stres is. Hierdie bioindikator moet egter verder in ander grondtipes en met ander tipes stres-induserende besoedeling ondersoek word. By bogenoemde bevindings is daar ook gevind dat die getalle grondprotosoë besonder gevoelig is vir Cu-geïnduseerde stres in grond met In lae pH. Dit is in ooreenstemming met die bevindings van andere met betrekking tot die bio-beskikbaarheid van swaar metale in grond met 'n lae pH. In dié tipe grond mag nutriëntsiklering as gevolg van protosoë aktiwiteit besonder gevoelig wees vir die negatiewe uitwerking van koper in die grond.
Keller, Thomas. "Soil compaction and soil tillage - studies in agricultural soil mechanics /." Uppsala : Dept. of Soil Sciences, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a489.pdf.
Full textChing, Peter. "Creep in sands a study of time dependent deformation of reclamation sand fill under constant effective stress /." Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B43894598.
Full textGavel-Solberg, Vegard. "Development and Implementation of Effective Stress Soil Models." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bygg, anlegg og transport, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26552.
Full textFernandez, Americo Leon. "Tomographic imaging the state of stress." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/20698.
Full textHo, Mei Yung. "Governing parameters for stress-dependent soil-water characteristics, conjunctive flow and slope stability /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202007%20HO.
Full textHoyos, Laureano R. Jr. "Experimental and computational modeling of unsaturated soil behavior under true triaxial stress states." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/32773.
Full textMun, Byoung-Jae. "Unsaturated soil behavior under monotonic and cyclic stress states." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1361.
Full textCopeland, Stephen Mark 1955. "Soil water potential as related to the Crop Water Stress Index of irrigated cotton." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276940.
Full textBloomer, S. T. "Stress-strain behaviour of soils containing electrolytes." Thesis, University of Sunderland, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381589.
Full textCunningham, Mark Robert. "The mechanical behaviour of a reconstituted, unsaturated soil." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/8699.
Full textSze, Hon-yue, and 施漢裕. "Initial shear and confining stress effects on cyclic behaviour and liquefaction resistance of sands." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45700837.
Full textLai, Chun Hon. "Experimental study of stress-dependent soil-water characteristics and their applications on numerical analysis of slope stability /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20LAIC.
Full textAl-Tabbaa, A. "Permeability and stress-strain response of speswhite kaolin." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382516.
Full textMaswoswe, Justice. "Stress paths for compacted soil during collapse due to wetting." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/8265.
Full textMohammad, Vali Samani Abbas. "Travel-time tomography for stress reconstruction in granular soil media." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22221.pdf.
Full textElder, Donald McGillivray. "Stress strain and strength behaviour of very soft soil sediment." Thesis, University of Oxford, 1985. http://ora.ox.ac.uk/objects/uuid:48050e2f-832d-47f4-9e3b-b922176f451b.
Full textManuel, Theodore Llewellyn. "Effect of soil nutrient status on stress tolerance in Proteaceae." Bachelor's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/25615.
Full textNguyen, Gia Huynh Truong. "Evaluating soil erodibility parameters with mini-JET under various soil moisture conditions." Kansas State University, 2016. http://hdl.handle.net/2097/34526.
Full textDepartment of Biological & Agricultural Engineering
Aleksey Y. Sheshukov
Soil erosion is one of the main reasons for agricultural land degradation in the world. Losses of land because of high soil erosion rates and rapidly expanding population result in significant reduction of cultivated land area per capita, and shortage of food on the global scale. Soil erosion can be a major source of sediment in the aquatic systems leading to reduction of organism population and poor water quality. Many factors affect soil erodibility, such as, soil properties, rainfall, topographic features, land use, and management practices, among others. The impacts of soil moisture content, however, are not well understood and. therefore, the primary goal of this study was to quantify two soil erodibility parameters, the erodibility coefficient and critical shear stress, under different soil moisture conditions using the jet erosion test (JET). The JET test uses the apparatus (called mini-JET) that creates an impinging jet of water into the soil and records the resulting scour depth over time. The scour depth time series are then fitted into a non-linear soil erosion equation, yielding the sought values of erodibility parameters. For this study, more than 40 soil samples were collected from several sites in Kansas, processed, and prepared to conduct JET tests in the lab setting. The effects of tillage and soil moisture content were of interest to this study. The results showed varied effects of soil type and sample soil moisture condition on the scour depth development and parameters sensitivity. The critical shear stress decreased and the erodibility coefficient increased with the increase of initial moisture content for clay loam soil, while critical shear stress did not change for sandy loam soil. The study also revealed higher erosive properties of soil collected from the tilled field compared to the no-till field.
Shibuya, Satoru. "Undrained behaviour of granular materials under principal stress rotation." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/7979.
Full textGriffiths, Robert Iwan. "Soil bacteria and carbon flux : the correlation with diversity and perturbation." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289179.
Full textUnutmaz, Berna. "Assessment Of Soil." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610285/index.pdf.
Full textJetchick, Elizabeth. "Stress, deformation and micromorphological aspects of soil freezing under laboratory conditions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0001/NQ32336.pdf.
Full textClinton, D. B. "The determination of soil parameters for design from stress path tests." Thesis, City University London, 1987. http://openaccess.city.ac.uk/8330/.
Full textMa, Qifu. "Soil salinity and water stress modify crop sensitivity to SO2 exposure." Thesis, Ma, Qifu (1993) Soil salinity and water stress modify crop sensitivity to SO2 exposure. PhD thesis, Murdoch University, 1993. https://researchrepository.murdoch.edu.au/id/eprint/42300/.
Full textAria, Shadi. "Load-settlement and stress-strain behaviour of geotextile-reinforced sandy soil." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2018. https://ro.ecu.edu.au/theses/2167.
Full textNaesgaard, Ernest. "A hybrid effective stress – total stress procedure for analyzing soil embankments subjected to potential liquefaction and flow." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/34004.
Full textChen, Rui. "Experimental study and constitutive modelling of stress-dependent coupled hydraulic hysteresis and mechanical behaviour of an unsaturated soil /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202007%20CHEN.
Full textWu, Dan Hua. "The effect of water potential on soil microbial biomass." Thesis, University of Aberdeen, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290290.
Full textZeywar, Nadim Shukry 1959. "Effect of sensor placement on the relationships of crop water stress index, soil moisture tension and soil moisture content." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/191981.
Full textIbarra, Sandra. "A model of stress distribution and cracking in cohesive soils produced by simple tillage implements /." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38205.
Full textThe problem was solved using fundamental principles of soil mechanics and force equilibrium analyzis. As a result, a mathematical model was developed which describes three failure zones within the cut soil volume. The model can be programmed into a computer to generate maps of normal and shear stresses to visualize the three failure zones.
The failure zones are the shear failure zone, the tensile fracturing zone and the no failure zone. The tensile fracturing zone is delimited by the tensile stress reaching the tensile strength of the soil at the given soil moisture content and soil density. The tensile strength of the soil was measured using an apparatus and method designed in this research.
The mathematical model gives an explanation of the mechanics of crumbling and the shape of the failed volume, but it does not give information concerning soil aggregate quality and arrangement within the soil furrow. Then, a method of analyzing the formed aggregates was developed which considers some soil physical properties of aggregates.
The study concluded that the smaller tool width and the smaller tool rake angle, among the ones used in this research, produced the most efficient geometry in producing the largest amount of soil break up, the most uniform aggregate formation and the most stable aggregate arrangement. The same tool geometry requires less energy per unit volume of soil disturbed. The best performance is produced at the lowest soil water content among those tested.
Tse, Man Kit. "Influence of stress states on soil-water characteristics, conjunctive surface-subsurface flow modelling and stability analysis /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202007%20TSE.
Full textLiao, Chung-Lon. "Applications of cone, vane and vane-cone to predict stress-strain behaviour of unsaturated cohesive soil." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72788.
Full textMellander, Per-Erik. "Spring water stress in Scots pine : interaction of snow and soil temperature /." Uppsala : Dept. of Environmental Assessment, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s287.pdf.
Full textFidelibus, Matthew, Chris Martin, and Jean Stutz. "Contributions of Beneficial Soil Fungi to Drought Stress Tolerance of Young Citrus." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/220566.
Full textEmam, Taraneh Megan. "The Role of Soil Biota, Abiotic Stress, and Provenance in Plant Interactions and Restoration." Thesis, University of California, Davis, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3706585.
Full textIn this dissertation, I asked how soil biota, abiotic stress, and plant provenance influence plant communities and interactions between plants. Soil biota can have positive or negative effects on individual plants, and also influence the diversity and productivity of plant communities through their net effects on individuals and by mediating plant-plant interactions. However, the level of abiotic stress experienced by plants is likely to drive plant responses to soil mutualists and antagonists. Additionally, plant provenance (e.g. population origin) can influence responses to abiotic soil conditions as well as to soil organisms. Understanding how these three interacting components shape plant interactions may improve success of restoration and invasive plant management. During restoration, the goal is typically to create conditions conducive to native plant reestablishment. However, amelioration of disturbed areas by reducing abiotic stress or by adding beneficial soil organisms may unintentionally increase colonization and growth of non-native plants. Using the applied context of mine restoration, I examined how soil biota, abiotic stress, and plant provenance affected plant communities and interactions in four studies.
In Chapter 1, I found that both a native grass (Bouteloua gracilis ) and an invasive grass (Bromus tectorum) responded positively to soil biota when grown alone in the greenhouse. However, when grown together, the presence of soil biota increased the competitive ability of Bromus, while the removal of soil biota increased competition by Bouteloua. Results supported the hypothesis that invasive species such as Bromus often have positive responses to soil biota in the invaded range, but I also found that Bromus response to soil biota removal varied considerably by site.
In Chapters 2 and 3, I examined how methods used during restoration (application of stockpiled soil and inoculation with soil biota) affected native and non-native plant growth in field plots. I found that native plant biomass and non-native plant biomass both tended to increase when soil abiotic stress was ameliorated through the addition of deeper stockpiled soil. In addition, both native and non-native grasses responded positively to the use of local soil an as inoculant, while non-native forbs responded negatively to local soil inoculum. However, native plants only received significant benefits from inoculation when targeted application to native seedling transplants was used. Commercial mycorrhizal fungal inoculum did not affect plant growth. In studies of both stockpiled soil addition and soil inoculation, year was an important factor in determining plant responses. Variation in effects by year may reflect differences in precipitation timing or amount, or changes associated with plant and soil biota growth over time.
In Chapter 4, I used a greenhouse experiment to examine how one type of soil biota, arbuscular mycorrhizal fungi (AMF), influenced plant-plant interactions. I also manipulated abiotic stress (soil phosphorus availability) and plant provenance (stress-tolerant ecotype versus competitive ecotype) to assess whether these factors influenced AMF-mediated interactions among plants. I found that allowing or denying AMF hyphal access between neighboring pots altered plant reproduction. Inflorescence production was substantially decreased when hyphal access was allowed between two stress-tolerant plants. In addition, when hyphal access was permitted from a stress-tolerant plant to a competitive plant, the competitive plant flowered slightly sooner, whereas allowing hyphal access between two stress-tolerant plants led to slightly slower flowering. These results did not appear to be driven by abiotic stress or plant nutrition. It is possible that AMF transmission of infochemicals may play a role in regulating plant phenology and reproduction; however, further research in this area is needed.
Salman, Talib H. "Triaxial behaviour of partially saturated granular soils at low stress levels." Thesis, University of Sheffield, 1995. http://etheses.whiterose.ac.uk/10232/.
Full textHenderson, Marc Bryson. "Changes in Streambank Erodibility and Critical Shear Stress Due to Surface Subaerial Processes." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33114.
Full textMaster of Science
Khan, Muhammad Umer Arif. "Experimental and mathematical investigations of soil-conduit interaction within a loaded soil slope." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2021. https://ro.ecu.edu.au/theses/2458.
Full textHermle, Sandra. "Reactions of a young forest ecosystem to heavy metal stress in the soil /." Zürich, 2004. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15723.
Full textDyer, M. R. "Observation of the stress distribution in crushed glass with applications to soil reinforcement." Thesis, University of Oxford, 1985. http://ora.ox.ac.uk/objects/uuid:98dee0c7-5e27-45b7-aef8-01bd56240671.
Full textALEIXO, MARCONI SOARES. "STRESS - STRAIN BEHAVIOR OF A GNEISS RESIDUAL SOIL USING THE CUBIC TRIAXIAL CELL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1998. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1526@1.
Full textO conhecimento do comportamento de solos residuais é de grande importância para projetos geotécnicos no Brasil e, em particular, na região do Rio de Janeiro, tendo em vista que o clima tropical e as características geológicas favorecem a ocorrência de mantos residuais de grande espessura. O presente trabalho trata do estudo do comportamento tensão-deformação de um solo residual proveniente de um perfil de alteração de rocha gnáissica do maciço da Tijuca, Rio de Janeiro. Como os solos residuais gnáissicos preservam as foliações herdadas da rocha matriz, investigou-se em particular a relevância de se considerar a ocorrência de anisotropia nas características de resistência e deformabilidade destes solos. No estudo foi utilizado o equipamento triaxial cúbico desenvolvido na PUC-Rio. Este equipamento possibilita o controle independente das três tensões principais, sendo mais adequado para a reprodução das trajetórias de tensões tridimensionais, usualmente associadas com obras geotécnicas no campo, e em particular, para estudos sobre as características de anisotropia de solos. O programa experimental constou de ensaios de compressão axial e hidrostática, sob condições drenadas de carregamento, utilizando o equipamento triaxial cúbico. Foram realizados também ensaios oedométricos convencionais, de modo a se obter as características de compressibilidade do solo. Foram moldados corpos de prova a partir de blocos indeformados, paralelos e perpendiculares à foliação observada no solo, o que possibilitou a análise dos resultados para direções distintas de carregamento. Para efeito de comparação sobre a relevância do arranjo estrutural dos grãos do solo, foram ensaiados também corpos de prova compactados dos mesmos materiais. A análise dos resultados permitiu a obtenção dos módulos de deformabilidade e dos parâmetros de resistência do solo residual. Em particular, foram verificados os efeitos da direção de carregamento dos corpos de prova, do nível das tensões de confinamento, do grau de intemperismo, do arranjo estrutural dos grãos e dos efeitos do grau de saturação. Pode-se concluir que os solos estudados não apresentaram efeitos marcantes de anisotropia nas características de resistência. No entanto, quanto à deformabilidade, pode-se considerar que o solo residual jovem apresentou características anisotrópicas.
The knowledge of the mechanical behaviour of residual soils is of great importance in geotechnical projects, because of its abundance in tropical regions, such as Brazil and particularly in the area of Rio de Janeiro. The present work presents a study on the fundamental stress-strain behaviour of a residual soil resulting from a profile of a gneiss rock in Rio de Janeiro. As the gneiss residual soils preservethe bedding planes from the parent rock, the relevance of considering anisotropy in the stress- strain characteristics of these soils was investigated. The cubic triaxial equipment developed at PUC-Rio was used in this research. This equipment allows the independent control of the three principal stresses, allowing the reprodution of three-dimensional stress paths, usually associated with geotechnical works in the field. The experimental program consisted of axial and hidrostatic tests, under drained loading conditions, using the cubic triaxial equipment. One- dimensional oedometer tests were also performed, in order to obtain the compressibility characteristics of the residual soil. Undisturbed specimens were prepared with the bedding planes parallel or perpendicular to the loading direction. Analysis of the test results showed the effects of load direction, confining stress level, weathering degree, structural soil fabric and saturation degree. It may be concluded that the gneiss residual soils which were selected for this research do not present significant effects of anisotropy in the strength characteristics. In the stress- strain characteristics, however, it may be concluded that the young residual soil showed effects of anisotropy.
EL conocimiento sobre el comportamiento de suelos residuales resulta de gran importancia para los proyectos geotécnicos en Brasil y, en particular, en la región de Rio de Janeiro, considerando que el clima tropical y las características geológicas favorecen la existencia de mantos residuales de gran espesor. El presente trabajo estudia el comportamiento tensión-deformación de un suelo residual proveniente de un perfil de alteración de roca gnáisica del macizo de la Tijuca, Rio de Janeiro. Como los suelos residuales gnáisicos preservan las foliaciones heredadas de la roca matriz, fue necesario estudiar si resultaba relevante considerar la aparición de anisotropía en las características de resistencia y deformabilidad de estos suelos. En el estudio se utilizó el equipo triaxial cúbico desarrollado en la PUC-Rio. Este equipo permite el control independente de las tres tensiones principales, siendo más adecuado para la reproducción de las trayectorias de tensiones tridimensionales, usualmente asociadas a obras geotécnicas en el campo, y en particular, para estudios sobre las características de anisotropía de suelos. El programa experimental incluyó ensayos de compresión axial e hidrostática, sobre condiciones drenadas de carga, utilizando el equipo triaxial cúbico. Fueron realizados también ensayos oedométricos convencionales, con el objetivo de obtener las características de compresibilidad del suelo. Fueron moldados cuerpos de prueba a partir de bloques no deformados, paralelos y perpendiculares a la foliación observada en el suelo, lo que permitió el análisis de los resultados para distintas direcciones de carga. Para efecto de comparación sobre la relevancia del arreglo extructural de los granos del suelo, se realizaron ensayos con cuerpos de prueba compactados de los mismos materiales. El análisis de los resultados permitió la obtención de los módulos de deformabilidad y de los parámetros de resistencia del suelo residual. En particular, se verificaron los efectos de la dirección de carga de los cuerpos de prueba, del nível de las tensiones de contensión, del grado de intemperización, de la disposición extructural de los granos y de los efectos del grado de saturación. Se puede concluir que los suelos estudiados no presentaran efectos marcantes de anisotropía en las características de resistencia. Sin embargo, con respecto a la deformabilidad, se puede considerar que el suelo residual joven presentó características anisotrópicas.
Corral, Jofré Gonzalo Andrés. "Re-analysis of deep excavation collapse using a generalized effective stress soil model." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60759.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 137-138).
This thesis re-analyzes the well-documented failure of a 30m deep braced excavation underconsolidated marine clay. Prior analyses of the collapse of the Nicoll Highway have relied on simplified soil models with undrained strength parameters based on empirical correlations and piezocone penetration data. In contrast, the current research simulates the engineering properties of the key Upper and Lower Marine Clay units using a generalized effective stress soil model, MIT-E3, with input parameters calibrated using laboratory test data obtained as part of the post-failure site investigation. The model predictions are evaluated through comparisons with monitoring data and through comparisons with results of prior analyses using the Mohr-Coulomb (MC) model. The MIT-E3 analyses provide a modest improvement in predictions of the measured wall deflections compared to prior MC calculations and give a consistent explanation of the bending failure in the south diaphragm wall and the overloading of the strut-waler connection at the 9th level of strutting. The current analyses do not resolve uncertainties associated with performance of the JGP rafts, movements at the toe of the north-side diaphragm wall or discrepancies with the measured strut loads at level 9. However, they represent a significant advance in predicting excavation performance based directly on results of laboratory tests compared to prior analyses that used generic (i.e., non site-specific) design isotropic strength profiles.
by Gonzalo Andrés Corral Jofré.
Civ.E.
Panwar, Anurag. "Determining the Effectiveness of Soil Treatment on Plant Stress using Smart-phone Cameras." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6346.
Full textMahaman, Sabiou 1957. "Nitrogen requirements of grain sorghum (Sorghum bicolor (L.) Moench) under soil moisture stress." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277251.
Full textWongareonwanakij, Sathaporn. "Effects of water stress and partial soil-drying on senescence of sunflower plants." Title page, contents and summary only, 1995. http://web4.library.adelaide.edu.au/theses/09A/09aw872.pdf.
Full textJessett, Clifford Alan. "Investigation of the liquefaction of a soil profile using in situ tests." Thesis, City University London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316399.
Full textMenkiti, Ogugua Christopher. "Behaviour of clay and clayey-sand, with particular reference to principal stress rotation." Thesis, Imperial College London, 1995. http://hdl.handle.net/10044/1/8035.
Full text