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1
Pearson, William W. "Residual soil nitrogen and nitrogen response of corn after alfalfa on sandy loam soil /." View abstract (PDF format), 2002. http://epapers.uwsp.edu/abstracts/2002/Pearson.pdf.
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Yiannakakis, Alexandros Emmanuel 1959. "Adsorption/desorption of phenols on the Pima clay loam soil." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276709.
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A linear distribution isotherm described the sorption/desorption of four phenols on the Pima clay loam soil. The linear distribution coefficients for 2,4-dichlorophenol, 2-chlorophenol, phenol and 2,4,6-trichlorophenol were 3.61, 2.93, 0.87, and 0.79. Ionization of the phenols affected their relative distribution order. Hydrogen bonding of phenols to exposed mineral sites accounted for the greater measured sorption than was predicted. The effect of solid concentration on the distribution of phenols was tested over a 10-fold soil/solution range. When a log transformation was performed on the data, a highly significant inverse relationship existed between the distribution of phenols and the soil/solution ratio. A 3-fold increase in the dissolved organic carbon in solution was associated with the decrease in the distribution coefficient. A 3-fold increase in the fraction organic carbon in the soil occurred when dry sludge solids were added to the Pima soil. A substantial increase in the dissolved organic carbon in solution was associated with the addition of sludge solids to the soil. (Abstract shortened with permission of author.)
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Mobbs, Tamara Leah. "Effects of four soil surfactants on four soil-water properties in sand and silt loam." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/t_mobbs_050110.pdf.
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Thesis (M.S. in biological and agricultural engineering)--Washington State University, May 2010.Title from PDF title page (viewed on June 23, 2010). "Department of Biological Systems Engineering." Includes bibliographical references (p. 16-22).
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Harper, Bruce. "An experimental and numerical modelling investigation of soil vapour extraction in a silt loam soil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/NQ40373.pdf.
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Hamelin, Joseph Paul Michel. "An experimental and numerical modelling investigation of soil vapour extraction in a silt loam soil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ39658.pdf.
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Teets, Paul D. "Analysis of macro-, micro-, and trace elements of soil samples from Sanborn field /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418071.
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Bardhan, Sougata. "BACTERIAL COMMUNITIES CAPABLE OF ENHANCED EPTC AND ATRAZINE DEGRADATION IN OHIO SILT LOAM AND SILTY CLAY LOAM SOILS." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276270673.
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Halpern, Moshe. "Tillage and residue management effects on soil organic matter dynamics in a sandy-loam." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32591.
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The accumulation and mineralization of soil organic matter is of great interest to both farmers and policy makers, because of its important functions in soil structure and in the global carbon cycle. The purpose of this study was to determine the long term effects of tillage practices and residue management on (1) the yield of Zea mays L. grown for corn grain or corn silage, (2) the size of the total soil organic carbon pool, (3) the relative sizes of the labile soil organic carbon and nitrogen pools, and (4) the size and structure of the microbial biomass. The experimental plots in Ste. Anne de Bellevue, Quebec, Canada were established on a sandy-loam soil in 1991 with a factorial design that includes three levels of tillage (no-till, reduced tillage, and conventional tillage), and two levels of residue input (corn roots and stover, corn roots only). At harvest in 2007, the corn grain yield was between 11.2 and 11.7 Mg dry matter ha-1, but not affected by tillage or residue treatments. Soils were collected from the plots following harvest at two depths: 0-5 cm and 5-20 cm. The total soil organic carbon pool contained between 37 and 58 Mg C ha-1 in the top 20 cm. There was no difference between tillage treatments, but the high residue plots had more soil organic carbon than the low residue input plots (P<0.05, Tukey test). Carbon and nitrogen mineralization during a 20 week laboratory incubation was used as an indicator of the relative size of the labile carbon and nitrogen pools under the different tillage and residue treatments. Both labile carbon and nitrogen pools were affected significantly by tillage and residue inputs. In the 0-5 cm depth, the labile carbon andL'accumulation et la décomposition de la matière organique du sol est de grand intérêt aux fermiers et aux décideurs politiques, en raison de ses fonctions importantes en structure de sol et dans le cycle de carbone global. Le but de cette étude était de déterminer les effets à long terme des pratiques de labourage et de la gestion de résidu sur (1) le rendement du Zea mays L. pour le maïs-grain ou le maïs d'ensilage, (2) la taille du réservoir de carbone organique du sol, (3) la quantité des formes labiles de carbone organique et d'azote organique du sol, et (4) la biomasse et la structure de la communauté microbienne. Les parcelles expérimentales à Ste-Anne-de-Bellevue, Québec, Canada ont été établies dans un sol sableux-loameux en 1991 avec un design factoriel qui inclut trois niveaux de labourage (semi-direct, labourage réduit et labourage conventionnel), et deux niveaux d'entrant de résidu (les racines plus la tige, les racines seulement). En 2007, le rendement de maïs-grain était entre 11.2 et 11.7 Mg matière sèche ha-1, mais non affecté par des traitements de labourage ou de résidu. Après la récolte, échantillons du sol ont été ramassés des parcelles à deux profondeurs : 0-5 cm et 5-20 cm. Le réservoir de carbone organique de sol a été entre 37 et 58 mg C ha-1 à une profondeur de 20 cm. Il n'y avait aucune différence entre les traitements de labourage, mais les parcelles avec haut résidu (racines plus tiges) ont eu plus de carbone organique de sol que lesquelles avec bas résidu (P<0.05, test de Tukey). La minéralisation de carbone et d'azote pendant une incubation de laboratoire durant 20 semaines a été employée com
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Bournival, Pierre. "Head losses and water distribution in a sandy loam soil with a subirrigation system." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64034.
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Lee, Sang Soo. "Soil surface-seal measurement using high-resolution x-ray computed tomography (HRCT)." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4507.
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Thesis (M.S.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 24, 2007) Vita. Includes bibliographical references.
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Elmi, Abdirashid A. "Denitrification in sandy loam soil as influenced by water table depth and nitrogen fertilization rate." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0003/MQ44163.pdf.
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Carre, Matthew Jon. "The dynamics of cricket ball impacts and the effect of pitch construction." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327664.
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Nava, Leon Jose Angel 1956. "CHLORIDE AND NITRATE DISTRIBUTION IN THE SOIL WITH FURROW AND BURIED DRIP IRRIGATION (SALINITY, SANDY LOAM)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276671.
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Van, Averbeke W., and JO Azeez. "Fate of manure phosphorus in a weathered sandy clay loam soil amended with three animal manures." Elsevier, 2009. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001448.
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Laboratory incubation was conducted for 120 days to study the fate of phosphorus in poultry (PM), cattle
(CM) and goat manures (GM). Phosphorus mineralized from manure was dependent on total P, Al and Fe
content. Manures improved P availability in the order: PM > CM > GM; however, the highest amount of P
was fixed or immobilized between 10 and 70 days of incubating with CM and GM. Fixation and immobilization
of mineralized P from poultry manure was negligible probably due to the high total P and the low
amount of Al and Fe. Generally, manure application reduced the ability of the soil to fix P. More than 90%
of the manure P was either immobilized or fixed by the soil. The relationship between the amount of P
released and time was cubic. Improvement of the C:P ratio of CM and GM would be an option to enhance
their agronomic use as fertilizer P source.
15
Jiang, Shuang. "Bacterial leaching from dairy shed effluent applied to a fine sandy loam under flood and spray irrigations." Lincoln University, 2008. http://hdl.handle.net/10182/668.
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Land application of wastes has become increasingly popular, to promote nutrient recycling and environmental protection, with soil functioning as a partial barrier between wastes and groundwater. Dairy shed effluent (DSE), may contain a wide variety of pathogenic micro-organisms, including bacteria (e.g. Salmonella paratyphyi, Escherichia coli. and Campylobacter), protozoa and viruses. Groundwater pathogen contamination resulting from land-applied DSE is drawing more attention with the intensified development of the dairy farm industry in New Zealand. The purpose of this research was to investigate the fate and transport of bacterial indicator-faecal coliform (FC) from land-applied DSE under different irrigation practices via field lysimeter studies, using two water irrigation methods (flood and sprinkler) with contrasting application rates, through the 2005-2006 irrigation season. It was aimed at better understanding, quantifying and modelling of the processes that govern the removal of microbes in intact soil columns, bridging the gap between previous theoretical research and general farm practices, specifically for Templeton soil. This study involved different approaches (leaching experiments, infiltrometer measurements and a dye infiltration study) to understand the processes of transient water flow and bacterial transport; and to extrapolate the relationships between bacterial transport and soil properties (like soil structure, texture), and soil physical status (soil water potential ψ and volumetric water content θ). Factors controlling FC transport are discussed. A contaminant transport model, HYDRUS-1D, was applied to simulate microbial transport through soil on the basis of measured datasets. This study was carried out at Lincoln University’s Centre for Soil and Environmental Quality (CSEQ) lysimeter site. Six lysimeters were employed in two trials. Each trial involved application of DSE, followed by a water irrigation sequence applied in a flux-controlled method. The soil columns were taken from the site of the new Lincoln University Dairy Farm, Lincoln, Canterbury. The soil type is Templeton fine sandy loam (Udic-Ustochrept, coarse loamy, mixed, mesic). Vertical profiles (at four depths) of θ and ψ were measured during leaching experiments. The leaching experiments directly measured concentrations of chemical tracer (Br⁻ or Cl⁻) and FC in drainage. Results showed that bacteria could readily penetrate through 700 mm deep soil columns, when facilitated by water flow. In the first (summer) trial, FC in leachate as high as 1.4×10⁶ cfu 100 mL⁻¹ (similar to the DSE concentration), was detected in one lysimeter that had a higher clay content in the topsoil, immediately after DSE application, and before any water irrigation. This indicates that DSE flowed through preferential flow paths without significant treatment or reduction in concentrations. The highest post-irrigation concentration was 3.4×10³ cfu 100 mL⁻¹ under flood irrigation. Flood irrigation resulted in more bacteria and Br⁻ leaching than spray irrigation. In both trials (summer and autumn) results showed significant differences between irrigation treatments in lysimeters sharing similar drainage class (moderate or moderately rapid). Leaching bacterial concentration was positively correlated with both θ and ψ, and sometimes drainage rate. Greater bacterial leaching was found in the one lysimeter with rapid whole-column effective hydraulic conductivity, Keff, for both flood and spray treatments. Occasionally, the effect of Keff on water movement and bacterial transport overrode the effect of irrigation. The ‘seasonal condition’ of the soil (including variation in initial water content) also influenced bacterial leaching, with less risk of leaching in autumn than in summer. A tension infiltrometer experiment measured hydraulic conductivity of the lysimeters at zero and 40 mm suction. The results showed in most cases a significant correlation between the proportion of bacteria leached and the flow contribution of the macropores. The higher the Ksat, the greater the amount of drainage and bacterial leaching obtained. This research also found that this technique may exclude the activity of some continuous macropores (e.g., cracks) due to the difference of initial wetness which could substantially change the conductivity and result in more serious bacterial leaching in this Templeton soil. A dye infiltration study showed there was great variability in water flow patterns, and most of the flow reaching deeper than 50 cm resulted from macropores, mainly visible cracks. The transient water flow and transport of tracer (Br⁻) and FC were modelled using the HYDRUS-1D software package. The uniform flow van Genuchten model, and the dual-porosity model were used for water flow and the mobile-immobile (MIM) model was used for tracer and FC transport. The hydraulic and solute parameters were optimized during simulation, on the basis of measured datasets from the leaching experiments. There was evidence supporting the presence of macropores, based on the water flow in the post-DSE application stage. The optimised saturated water content (θs) decreased during the post-application process, which could be explained in terms of macropore flow enhanced by irrigation. Moreover, bacterial simulation showed discrepancies in all cases of uniform flow simulations at the very initial stage, indicating that non-equilibrium processes were dominant during those short periods, and suggesting that there were strong dynamic processes involving structure change and subsequently flow paths. It is recommended that management strategies to reduce FC contamination following application of DSE in these soils must aim to decrease preferential flow by adjusting irrigation schemes. Attention needs to be given to a) decreasing irrigation rates at the beginning of each irrigation; b) increasing the number of irrigations, by reducing at the same time the amount of water applied and the irrigation rate at each irrigation; c) applying spray irrigation rather than flood irrigation.
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Kurtz, Frederick C. "The mobility of malathion in a silt loam soil as affected by phosphate and naturally occuring organic acids." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/40648.
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Qiao, Shuang Ye. "Modeling water flow and phosphorus fate and transport in a tile-drained clay loam soil using HYDRUS (2D/3D)." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123033.
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Phosphorus (P) is an important agricultural non-point source pollutant that could contribute to eutrophication of surface waters. In this study, the HYDRUS (2D/3D) model was evaluated for simulation of water flow and P transport in a clay loam soil in southern Ontario. The model was calibrated and validated using field data from two 0.1 ha test plots between 2008-2011. These plots have controlled tile drainage and a corn-soybean crop rotation. The surface and sub-surface water flows in test plots were monitored and samples collected continuously year round using an auto-sampling system. The model simulated water flow and P relatively well, with weekly modeling efficiency of 0.513 to 0.738 for validation of water flow, and weekly modeling efficiency of 0.587 to 0.768 for validation of dissolved P loss in tile drainage. Most of the deviation of simulated water flow occurred between November to February, which suggests the model would greatly benefit from optimization of snow dynamics and frozen soil conditions. Some of the simulation errors may also be attributed to soil cracking in the summer which consequently enhanced macropore flow. The model predicted daily water flow poorly, suggesting presence of time lag between simulation and measurements. Limitations of the model include lack of simulation of particulate P loss and surface runoff P loss. This model should be tested further for other soils in southern Ontario as well as other parts of Canada before its validity can be established.Le phosphore (P) est un important polluant de sources diffuses qui pourrait contribuer à l'eutrophication des eaux de surface. Dans cette étude, la capacité à simuler le débit de l'eau et le transport de P dans les sols argileux ou limon argileux du Sud de l'Ontario du modèle HYDRUS (2D/3D) a été évalué. Le modèle a été calibré et validé utilisant des données de terrain de deux parcelles d'essai de 0.1 ha entre 2008 et 2011. Ces parcelles ont contrôlées le drainage et la rotation des cultures de maïs et de soya. Les écoulements des eaux de surface et dans le sol inclus dans les parcelles d'essai ont été contrôlés et les échantillons collectés continuellement toute l'année à l'aide d'un système d'échantillonnage automatisé. Le modèle a relativement bien simulé le débit de l'eau et le P, avec des efficacités de modélisation sur une base hebdomadaire de 0.513 à 0.738 pour la validation du débit de l'eau, et une efficacité de modélisation sur une base hebdomadaire de 0.587 à 0.768 pour la validation de la perte du P dissous dans le réseau de drainage. Une déviation du débit de l'eau simulé est survenue davantage entre les mois de novembre et février, ce qui suggère que le modèle aurait avantage à s'attarder à l'optimisation de la dynamique de la glace et de la neige sur les conditions du sol. Certaines des erreurs de simulation peuvent être attribuées aux fissures dans le sol qui surviennent en été, qui conséquemment, favorisent la circulation des micropores. Le modèle prédit mal le débit de l'eau journalier, démontré par la présence de décalage temporel entre la simulation et les prises de mesure. Les limites du modèle incluent un manque de simulation de la perte de la matière particulaire P et de la perte P en écoulement de surface. Ce modèle devra être testé davantage sur d'autres sols dans le Sud de l'Ontario ainsi que sur d'autres régions du Canada avant sa validité puisse être reconnue.
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Andrews, Aaron A. "Phosphorus loss with surface runoff as affected by bioenergy-based residue and nutrient management systems for an Iowa loam soil." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1475914.
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Landzela, Besule. "Effects of BT Maize (MON810) crop and its residues on selected soil biological properties and N and P release in a sandy loam soil from Alice, Eastern Cape, South Africa." Thesis, University of Fort Hare, 2013. http://hdl.handle.net/10353/d1007542.
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There are apprehensions that genetic modification of maize with Bacillus thuringiensis (Bt) may have negative effects on soil biodiversity, ecosystem processes and functions. This study aimed at determining the effect of Bt maize crop, Bt maize residues and its genetic modification on microbial biomass carbon (MBC), selected enzyme activities, vesicular arbuscular mycorrhizal (VAM) fungi and N and P release patterns. The study was conducted under field, glasshouse and laboratory conditions. In 2010/2011 season, four maize cultivars; DKC 61-25B (Bt), DKC 61-24 (non-Bt), PAN 6Q-321B (Bt) and PAN6777 (non-Bt) were planted. Determination of MBC, enzyme activities and fungal spore count was done at 42, 70, and 105 days after planting (DAP). A loam soil amended with Bt or non-Bt maize leaf residues from a study of 2009/2010 season was incubated to investigate effects of Bt maize residues on MBC and soil enzyme activities. Leaf residues of Bt and non-Bt maize cultivars (DKC 61-25B, DKC 61-24, PAN 6Q-321B and PAN6777) were used and soil without residues was used as a control. Samples were collected at 7, 28 and 56 days of incubation (DOI). An incubation study was also carried out in the laboratory to determine the effect of Bt maize residues (i.e. leaf, stem and root) and its genetic modification on N and P release patterns. Residues of DKC 61-25B, DKC 61-24, PAN 6Q-321B and PAN6777and soil without residues as a control were incubated in the laboratory. After destructive sampling at 0, 7, 14, 28, and 56 DOI, N in the form of NH4-N and NO3-N and P mineralisation were determined. Amendment of soil with residues enhanced MBC (p < 0.05) at all the sampling dates. For example MBC increased from 95 in the control to 146.3 mg/kg in the DKC 61-25B treatment at the end of the glasshouse trial. In the field DKC 61-25B had 9.1 mg/kg greater MBC than DKC 61-24, while PAN 6Q-321B had 23.9 mg/kg more MBC than PAN6777 at the end of the trial. However, no differences (p < 0.05) were observed in enzyme activities under field and glasshouse conditions except for dehydrogenase that had greater activity where DKC 61-25B and PAN 6777 were grown. There were no differences between the type of residues (Bt and non-Bt) on enzyme activities tested. However, differences were observed among the sampling dates. No effects of Bt maize crop on fungal spore count were observed. Similarly no differences were observed in leaf, stem and root tissues composition between Bt and non-Bt maize cultivars. Net N and P mineralisation from Bt maize cultivars did not differ from that of non-Bt maize cultivars. However, differences were observed among the cultivars. The results of this study suggested that Bt maize with Bt MON810 event can be grown in the central region of the Eastern Cape (EC), South Africa without affecting MBC, soil enzyme activities, VAM, and release of N and P nutrients from its residues.
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Areghan, Joseph I. "Settlement Behavior of a Sandy Loam Due to Suction Changes Associated with Simulated Artificial Tree Roots." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23514.
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Shallow foundations rested on Leda clay that are widely distributed in Eastern Canada exhibit shrinkage characteristics and are prone to differential settlements. Due to this reason, significant repairs are necessary to the foundations and basements of residential structures constructed in Leda clay deposits. Differential settlements are commonly attributed to the changes in the natural water content of soils associated with water infiltration, evaporation or plant transpiration (i.e., tree-roots-suction). Various research studies have been undertaken to estimate the possible settlements of shallow foundations associated with the water infiltration or evaporation. Several thumb rules have been proposed through research studies, providing recommendations with respect to the distance at which trees must be planted as a function of their heights at maturity such that differential settlements can be avoided. However, limited studies have been carried out to estimate or model the settlements of shallow foundations taking into account the influence of tree-roots-suction.
In the present research program, a comprehensive experimental study regarding the deformation characteristics of a sandy loam soil from Ottawa due to tree-root-suction is undertaken, using specially designed equipment. The study has been undertaken using a sandy loam soil so that the testing program can be conducted in a shorter period of time. An artificial rooting system (ARS) was designed and placed in a specially designed tank at the University of Ottawa to simulate tree-roots-suction and measure soil surface settlements associated with a decrease in natural water content (or increase in soil suction) using particle image velocimetry (PIV) technique. The ARS consists of an artificial root, suction generator, matric suction and volumetric water content monitoring devices. The variation of matric suction and volumetric water content are monitored at various depths using the instrumentation of the ARS. Based on the results of the experimental studies, a methodology is proposed to model the settlement behaviour of sandy loam soils due to suction from ARS, using commercial finite element software, SEEP/W and SIGMA/W (i.e. software package of GeoStudio 2007). The study offers a reasonably good comparison between the measured surface settlements and those estimated using the finite element modelling analysis. The modelling methodology presented in this thesis is promising and may be extended for estimating the settlement behaviour associated with the tree roots suction of Leda clay deposits and to other soils.
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Shoko, Munashe. "Exploring phosphorus, mucuna (Mucuna pruriens)and nitrogen management options for sustainable maize production in a depleted kaolinitic sandy loam soil of Zimbabwe." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1364.
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Thesis (PhD(Agric) (Agronomy))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: Continuous cropping without replenishing the nutrient component of soils will eventually lead to the depletion of soil nutrients. Small scale farmers in Zimbabwe often do not have the financial means to buy fertilizer and this problem is exacerbated by scarcity of commodities such as fertilizers. The use of herbaceous legumes such as mucuna (Mucuna pruriens) can assist to recapitalize soil fertility depletion and improve subsequent maize productivity in sandy loam soils in the small holder farming sector of Zimbabwe. In this study the effect of phosphorus (P) application to a mucuna crop, the effect of mucuna management options and the application of nitrogen (N) to the subsequent maize crop was investigated. The experiment was carried out during the 2007 to 2009 seasons at the Grasslands Research Station in Marondera in Zimbabwe. The soils are classified as humic ferrolsols and are predominantly of the kaolinitic order with sandy loams of low fertility and are slightly acid (pH CaCl = 5.2). A randomized complete block design was used for the effect of P on mucuna productivity and the effect of P and mucuna management options on the soil properties. The treatments were two P rates (P0 and P40 = 0 kg P ha-1 and 40 kg P ha-1 respectively) applied to a preceding mucuna crop, four mucuna management options [1) fallow (F) (no mucuna planted = control), 2) mucuna ploughed-in at flowering (MF), 3) all mucuna above ground biomass removed at maturity and only roots were ploughed-in (MAR) and 4) mucuna pods removed and the residues ploughed-in (MPR)]. A split-plot design was used to study the effect of P application to mucuna, mucuna management options and N rates on the growth and yield of the subsequent maize crop. The four N treatments [N0 = 0 kg N ha-1, N40 = 40 kg N ha-1, N80 = 80 kg N ha-1 and iv N120 = 120 kg N ha-1] were applied to a subsequent maize crop. Growth and development parameters such as biomass production, leaf area index, nutrient content of the foliage and grain yield were determined in the mucuna and maize crops. Soil parameters investigated included nutrient content, pH, bulk density and porosity. Phosphorus application in these particular soil conditions positively influenced mucuna biomass production and therefore enhanced the role of mucuna as a rotational crop by increased positive effects on the subsequent maize crop. The incorporation of above-ground biomass of mucuna had positive effects on all soil properties investigated. The MF and MPR management options increased the soil organic matter (OM) and reduced bulk density which leads to an improvement in porosity (f) of the soil. Mucuna incorporated at flowering (MF) and P40 treatment combination resulted in the highest mineral N, P, potassium (K), calcium (Ca) and magnesium (Mg) levels. A significant three-way interaction (P<0.05) between mucuna management options, nitrogen rates and time was observed in terms of biomass production and all nutrients in the leaves of the subsequent maize crop. The main findings were that the MF management option had the highest biomass and foliar nutrient accumulation through-out all the treatment combinations. In general the MF management option gave the highest maize yield across all the treatment combinations. Incorporation of mucuna biomass into the soil prior to planting a maize crop therefore improve soil physical and chemical qualities resulting in improved soil conditions for a subsequent maize crop which in turn lead to higher maize yields. Including a mucuna rotational crop have a similar effect on maize yield than application of 80 kg ha-1 of fertilizer N.
AFRIKAANSE OPSOMMING: Aanhoudende verbouing van gewasse op dieselfde grond sonder om voedingstowwe aan te vul lei uiteindelik tot die agteruitgang van die grond se vrugbaarheid. Kleinboere in Zimbabwe het meestal nie die finansiële vermoëns om bemestingstowwe te koop nie en die probleem word vererger deur die onbekombaarheid van kommoditeite soos bemestingstowwe. Die gebruik van kruidagtige peulplant gewasse soos mucuna (Mucuna pruriens) kan bydra om grondverarming teen te werk en om die produksie van ‗n daaropvolgende mielie aanplanting in sandleemgronde in ‗n kleinboerstelsel in Zimbabwe te verhoog. In hierdie studie is die invloed van fosfor (P) toediening aan ‗n mucuna aanplanting, die invloed van bestuursopsies van die mucuna en die toediening van stikstof (N) aan die daaropvolgende mielie aanplanting ondersoek. Die eksperiment is tydens die 2007 tot 2009 reënseisoen by die Grasslands Research Station in Marondera in Zimbabwe uitgevoer. Die grond word geklassifiseer as humiese ferrolsols en is hoofsaaklik sanderige leemgrond van die kaolinitiese orde met lae vrugbaarheid en is effens suur (pH CaCl = 5.2). ‘n Volledig ewekansige blokontwerp is gebruik om die invloed van P op die produktiwiteit van mucuna te bepaal asook die invloed van P toediening en mucuna bestuursopsies op grondeienskappe. Die behandelings was twee P vlakke (P0 = 0 kg P ha-1 en P40 = 40 kg P ha-1) wat aan ‗n voorafgaande mucuna aanplanting toegedien is, vier mucuna bestuursopsies [1) braak (F) (geen mucuna geplant = kontrole), 2) mucuna ingeploeg met blomtyd (MF), 3) alle bogrondse mucuna biomassa verwyder by rypwording en slegs wortels ingewerk (MAR) en 4) mucuna peule verwyde en die res van die bogrondse material ingeploeg (MPR)] en vier N behandelings [N0 = 0 kg N ha-1, N40 = 40 kg N ha-1, N80 = 80 kg N ha-1 en N120 = 120 kg N ha-1] toegedien aan ‗n daaropvolgende mielie aanplanting. Groei en ontwikkeling parameters soos biomassa produksie, blaaroppervlakindeks, nutriëntinhoud van die blare en graanopbrengs is in die mucuna en mielie aanplantings ondersoek. Grondeienskappe soos nutriëntinhoud, pH, bulkdigtheid en porositeit is gemeet. Fosfaat toediening aan hierdie spesifieke grondtipe het mucuna produksie positief beïnvloed en dus die rol van mucuna as rotasiegewas verbeter deur positiewe reaksies in die daaropvolgende mielie aanplanting. Die inwerk van bogrondse mucuna biomassa het al die fisiese grondeienskappe wat ondersoek is positief beïnvloed. Die MF en MPR bestuursopsies het organiese materiaal inhoud van die grond verhoog en bulkdigtheid verlaag wat lei tot verbeterde grondporeusheid (f). Mucuna wat tydens blomvorming ingewerk is (MF) lei tot die hoogste minerale N, P, kalium (K), kalsium (Ca) en magnesium (Mg) vlakke. ‗n Betekenisvolle drie-rigting interaksie (P < 0.05) tussen mucuna bestuursopsies, N vlakke en tyd is waargeneem in terme van biomassa produksie en in terme van al die nutriëntvlakke in die mielieblare wat ondersoek is. Die hoofbevindinge was dat die MF bestuursopsie die hoogste biomassa produksie en blaarnutriënt akkumulasie oor alle behandelingskombinasies tot gevolg gehad het. In die algemeen het die MF bestuursopsie die hoogste mielie-opbrengs oor alle behandelingskombinasies tot gevolg gehad. Die inwerk van mucuna materiaal in die grond voordat mielies geplant word verbeter dus fisiese en chemiese toestande in die grond wat grondtoestande verbeter vir die daaropvolgende miegewas en uiteindelik lei tot hoër mielie-oeste. Die insluiting van mucuna as ‘n rotasiegewas het diesefde effek op mielie-opbrengs as die toediening van 80 kg ha-1 N bemesting.
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Staugaitienė, Rūta. "Effect of different sulphur fertilisation rates on plant productivity and on changes in sulphur content in soil and plants." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140910_144606-11913.
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Objective of the research – the research was to determine the effect of different sulphur fertilisation rates on the mineral sulphur content in soil and the seed/grain yield and quality of spring rape and spring wheat crops grown on low in sulphur sandy light loam Epicalcari – Endohypogleyic Cambisols and very low in sulphur sandy loam on light loam Orthi-Haplic Luvisols. Tasks of the research: To determine the effect of different sulphur fertilisation rates applied to low in sulphur sandy light loam Epicalcari – Endohypogleyic Cambisols and very low in sulphur sandy loam on light loam Orthi-Haplic Luvisols on: • Spring rapeseed yield and crop structural elements; • Spring rapeseed quality; • Spring wheat yield and crop structural elements; • Spring wheat grain quality; • Changes in the mineral sulphur content in soil.Tyrimų tikslas – nustatyti skirtingų sieros trąšų normų įtaką vasarinių rapsų ir vasarinių kviečių derliui, jo kokybei bei mineralinės sieros kiekiui mažai ir labai mažai sieringame smėlingame lengvo priemolio sekliai karbonatingajame giliau glėjiškajame rudžemyje (Epicalcari – Endohypogleyic Cambisol ) ir priesmėlio ant lengvo priemolio tipingajame paprastajame išplautžemyje (Orthi-Haplic Luvisol). Tyrimų uždaviniai: Nustatyti sieros trąšų normų įtaką mažai ir labai mažai sieringame smėlingame lengvo priemolio sekliai karbonatingajame giliau glėjiškajame rudžemyje (Epicalcari – Endohypogleyic Cambisol ) ir priesmėlio ant lengvo priemolio tipingajame paprastajame išplautžemyje (Orthi-Haplic Luvisol): • Vasarinių rapsų sėklų derliui ir struktūros elementams. • Vasarinių rapsų sėklų kokybei. • Vasarinių kviečių derliui ir struktūros elementams • Vasarinių kviečių grūdų kokybei. • Mineralinės sieros kiekio pokyčiams dirvožemyje.
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Erdem, Ziya. "Bioremediation potential of 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) from a sandy-loam soil using aerobic bacteria Alcaligenes eutrophus A5, Corynebacterium sp. and a mixed culture." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468933721.
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Bullmann, Heike. "Eigenschaften und Genese periglazialer Deckschichten auf Carbonatgesteinen des Muschelkalks in einem Teilgebiet der ostthüringischen Triaslandschaft." Doctoral thesis, Universitätsbibliothek Leipzig, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-67899.
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Periglaziale Deckschichten auf carbonatreichen Gesteinen der geologischen Formation des Muschelkalks sind bisher nur peripher Gegenstand wissenschaftlicher Untersuchungen innerhalb der Deckschichtenfor-schung. Um diese Lücke zu schließen, widmet sich die vorliegende Arbeit dem Aufbau des oberflächenna-hen Untergrundes im Muschelkalk in einem Teilgebiet in der ostthüringischen Triaslandschaft.
Die Ergebnisse zeigen, dass die periglazialen Deckschichten in Abhängigkeit von lithologischen Gesteins-merkmalen und Relieffaktoren (Exposition, Neigung) eine hohe räumliche Heterogenität hinsichtlich der stoff-lichen Zusammensetzung, der vertikalen Gliederung und Gründigkeit aufweisen. Sie sind in Basislagen (LB), Mittellagen (LM) und Hauptlagen (LH) gegliedert, die ihrerseits eigenständige Schichten beinhalten können. Die Lagenbildungen über carbonatreichen Gesteinen des Muschelkalks weisen Besonderheiten im Aufbau, in den stofflichen Eigenschaften und in ihrer Genese auf.
Die Basislagen sind in der Regel mehrgliedrig entwickelt und können bis zu drei, faziell zu unterscheidende Substratkomplexe enthalten. Dies sind i) eine skelettfreie Kalksteinbraunlehm-Fließerde (LB-F), ii) ein Kalk-steinbraunlehmschutt (LB-1) und iii) ein Kalksteinschutt (LB-2). Die Zweiteilung der Basislagenschutte sowie die Abfolge LB-1/ LB-2 (LB-1 über LB-2) können als charakteristische Merkmale der Basislagenbildung über Muschelkalk herausgestellt werden. Skelettfreie Kalksteinbraunlehme (LB-F) stellen eine Besonderheit auf Carbonatgesteinen dar, da vergleichbare Bildungen auf quarz- und silikatreichen Standorten fehlen. Die Hauptlagen werden in eine schluffreiche (LH) und tonreiche (LHT) Fazies unterschieden. Beide zeichnen sich durch eine vollständige Skelettfreiheit aus, die ebenfalls als übergreifendes Merkmal über Muschelkalk gelten kann. Zwei Mittellagentypen sind mit skelettfreier Mittellage (LM) und skeletthaltiger Mittellage (LMs) vertreten.
Die Genese der Basislagenabfolge LB-F/ LB-1/ LB-2 fand vollständig im Weichselglazial statt und schließt eine periglaziale Genese der Kalksteinbraunlehme ein. Die Beteiligung von Spülprozessen an der (Geli-) Solifluktion hat die Akkumulation von Lösungsrückständen (= Kalksteinbraunlehm) gefördert. Die Zweiteilung der Basisschutte kann ebenfalls durch die Mitwirkung ablualer Prozesse erklärt werden. Die Kalksteinbraun-lehm-Fließerde entstand synsedimentär zur Bildung der Basislagenschutte durch laterale Ausspülung. Die Variabilität der Lössedimente wird neben Luv-/Lee-Effekten und präsedimentäre karstartige Hohlformen vor allem auch über eine differenzierte periglaziale Bodenfeuchte- und Vegetationsverteilung gesteuert.
In der Arbeit wurden u.a. der gU/fU-Quotient, pedogene Eisenoxide (Feo, Fed), Gesamteisengehalt (Fet), Fet/Ton-Quotient und (Fed-Feo/(Fet/Ton)-Quotient (nach GÜNSTER et al. 2001) sowie die Korrelation von Tongehalt und pedogenem Eisen für alle oben genannten Substrate ermittelt. Eine integrative Betrachtung dieser Parameter ist grundsätzlich geeignet, primäre Sedimenteigenschaften der Substrate herauszustellen und eine pedogenetische Überprägung abzugrenzen. Darüber hinaus erlauben sie Aussagen zur Genese.
Der Tongehalt der Mittellagen konnte neben der Überformung durch Tonverlagerung als sedimentogene Ei-genschaft belegt werden. Kalksteinbraunlehme mit weniger als 65% Tongehalt müssen nicht grundsätzlich lösslehmbeeinflusst sein. Rezente Lösungsprozesse und eine rezente Weiterbildung der Kalksteinbraunleh-me konnten auch im Liegenden mächtigerer Lösssedimente nachgewiesen werden.
Es wird gezeigt, wie die periglazialen Decksedimente in ihrer räumlichen, vertikalen und stofflichen Variabilität Einfluss auf die Heterogenität der Bodendecke nehmen.
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Costa, d'Aguiar Sofia. "Numerical modelling of soil-pile axial load transfer mechanisms in granular soils." Châtenay-Malabry, Ecole centrale de Paris, 2008. http://www.theses.fr/2008ECAP1075.
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L’objectif du travail présenté dans cette thèse est l'analyse et modélisation numérique des mécanismes de transfert de charge axiale entre sol-pieu, dans les sols granulaires. En utilisant un modèle élastoplastique tridimensionnel d'élément finis, une attention particulière est prêtée à la modélisation du comportement de l’interface sol-structure. Ainsi, les outils numériques nécessaires ont été mis en place et les outils existants ont été améliorés afin que, l'analyse de l'interaction sol-pieu soit faisable. Deux nouveaux modèles de comportement 3D sont implémentés dans le code d'éléments finis GEFDYN: un modèle d'interface et, pour le sol, une formulation axisymétrique du modèle multimécanismes de l’ECP, déjà existant et également connus sous le nom de Hujeux. La performance des deux modèles de comportement est comparée avec des résultats expérimentaux: d'abord, en utilisant des essais directs de cisaillement sol-structure et ensuite des essais de charge statiques de pieux en modèle physiques de centrifugeuse. La formulation théorique et l'exécution numérique des modèles constitutifs se sont donc avérées adéquats pour l'analyse des mécanismes de transfert de charge de sol-pieux, pour différents états initiaux du sol, différentes rugosités de la surface sol-pieux et différentes géométries. Finalement, l'applicabilité des modèles proposés est également étudiée pour un cas d’étude réel d’essais de charge statique de pieux forés et à tarière continus, menés dans le site expérimental ISC2 à l’occasion de la 2nd International Conference on the Site Characterization. L’identification des paramètres du sol et la simulation des essais de charge in-situ a été réalisé avec succésThe purpose of the work presented in this thesis, which has a theoretical and numerical character, is the analysis and numerical modelling of soil-pile load transfer mechanisms, in granular soils, when the pile is subjected to axial vertical loads. In the three dimensional elastoplastic finite element model used, particular attention is paid to modelling soil-structure interface behavior. The necessary numerical tools were implemented and the existing ones enhanced so that, the analysis of the soil-pile interaction problem is feasible. Two newly implemented 3D constitutive laws, in the GEFDYN finite element code, are proposed: an interface model and, for soil, an axisymmetric formulation of the existing ECP multimechanism model, also known as Hujeux model. The performance of both constitutive models is compared with experimental results. First, using soil-structure direct shear tests and then, using results of static pile load tests of centrifuge physical models. The theoretical formulation and numerical implementation of the constitutive models proved to be adequate for the analysis of the soil-pile load transfer mechanisms for different soil initial states, soil-pile surface roughness conditions, and different geometries. Finally, the applicability of the proposed models, is also studied for a real case study of pile static load tests carried out in the ISC'2 experimental site, at the occasion of the 2nd International Conference on the Site Characterization. Soil’s laboratory characterization tests and in-situ pile static load tests on bored and CFA piles are simulated, and results successfully compared
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Brouard, Christine. "Contribution à l'étude de la rétention de phénylurées (herbicides) par des adsorbants modèles et des sols." Angers, 1995. http://www.theses.fr/1995ANGE0006.
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Notre objectif était d'étudier la rétention d'herbicides de la famille des phenylurées sur des adsorbants minéraux et dans le sol. Les molécules retenues sont le chloroxuron, le chlortoluron, le metobromuron, l'isoproturon et le difenoxuron. Les adsorbants utilises sont la celite, le florisil, l'alumine, le carbonate et le sulfate de calcium. Les sols étudiés sont un sol limoneux-argileux et un sol limoneux-sableux. Nous poursuivons le double but analytique et environnemental d'améliorer les étapes de purification par chromatographie d'adsorption d'extraits en vue de l'analyse de résidus, et de prévoir leur dispersion dans le sol, leur diffusion en direction des nappes et leur exposition à la dégradation microbienne. La méthode suivie passe essentiellement par le tracé de cinétiques et d'isothermes d'adsorption-désorption, et de courbes de mobilité en présence d'eau ; les variations de concentrations des urées dans la phase liquide ont été mesurées par HPLC-UV. Les isothermes ont été modélisées dans les formalismes de Freundlich, Langmuir et Temkin. Les influences sur la mobilité des urées dans des colonnes de sol, de la concentration saline de la phase aqueuse (cacl#2) et de formulants tensio-actifs (polyphénols ethoxyles) ont été évaluées par la même méthodologie. Ces études ont été complétées par l'examen de spectres IR pour caractériser les groupes structuraux de ces molécules engagés dans leur liaison avec les adsorbants. Nous mettons en évidence le rôle privilégié des groupes phenoxy dans l'adsorption sur le florisil ; des effets hydrophobes dus à la substitution des noyaux aromatiques par le chlore pourraient être à l'origine de la rétention du chloroxuron et du chlortoluron sur tous les adsorbants, et la combinaison d'effets stériques dus à la taille du brome, d'effets électroniques et dipolaires dus au groupe methoxy sur la fonction urée pourraient intervenir dans la faible rétention du metobromuron sur tous les adsorbants. Enfin parmi les formulants étudiés, seul le soprophor FL à une concentration supérieure à 0,05 g/l a un effet accélérateur marqué sur la mobilité de l'isoproturon en colonnes de sol.
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Bhattacharyya, Ranjan. "Using palm-mat geotextiles for soil conservation on arable loamy sands in the United Kingdom." Thesis, University of Wolverhampton, 2009. http://hdl.handle.net/2436/88536.
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To date, most studies on the effectiveness of geotextiles on soil erosion rates were conducted in laboratory experiments for <1 h. Hence, at Hilton, East Shropshire, UK, this study investigated the effectiveness of palm-mat geotextiles (Borassus and Buriti mats) in reducing rainsplash erosion, runoff and soil loss and changing selected soil properties under field conditions over two years (January 2007-January 2009). Mat-cover effects on rainsplash erosion were studied in two sets on a loamy sand soil (0o slope). In both sets, six randomly-selected plots (each 1 m2) were completely matcovered and six were bare. Unlike Buriti mats, Borassus mat-cover on bare soil significantly (P<0.001) decreased rainsplash erosion (by ~89%). Duplicate runoff plots (10 x 1 m on a 15o slope) had five treatments (bare, permanent grass, Borassus completely-cover, Borassus buffer strip and Buriti buffer strip). Using Borassus buffer strips (area coverage ~10%) on bare soil decreased runoff by ~71% (P>0.05) and soil erosion by ~92% (P<0.001). Borassus buffer strip, Buriti buffer strip and Borassus completely-covered plots had similar effects in decreasing runoff and soil loss. However, the longevity of Borassus mats was ~twice that of Buriti mats. Despite physical protection, runoff control and sediment entrapment, biomat buffer zones may considerably alter and protect flow direction by presenting barriers and creating several cross-drains. Except Borassus completely-covered plots, all plots had significant (P<0.05) increases in topsoil (0-5 cm) bulk density and decreased aggregate stability. However, buffer strips were more effective in trapping fine particles than Borassus completely-covered plots. No treatments had significant (P>0.05) effects on changes in pH, soil organic matter, total soil carbon or N. Plots with Borassus mats significantly (P<0.05) increased total P and decreased total Ca. Treatments had no significant effects on changes in total S, Mg, Zn, Cu, Fe, Mn, Mo or Cl concentrations. Borassus buffer strips can effectively conserve soil and water and improve and maintain selected soil properties, with results similar to Borassus completely-covered plots. The mechanisms explaining the effectiveness of buffer zones require further studies under varied pedo-climatic conditions.
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Ugarte, Nano Claudia Carolina. "Etude de la variabilité des propriétés physiques et hydrodynamiques d'un sol argileux sous l'effet de conduites en protection intégrée contre les adventices." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS003/document.
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Les systèmes de culture en Protection Intégrée de Cultures contre les adventices (systèmes PIC-adventices) sont d’un grand intérêt pour réduire significativement l’utilisation des herbicides en les substituant par une combinaison complexe de différentes techniques culturales. L’objectif principal de notre travail a été de contribuer au volet environnemental de l’évaluation multicritère des systèmes PIC-adventices mis en place depuis 2000 sur le domaine expérimental de l’INRA à Bretenière (21). La variabilité des propriétés physiques et hydrodynamiques qui interviennent dans le transfert de l’eau dans le sol a été étudiée dans les 5 systèmes de culture présents sur le site (1 système de référence et 4 systèmes PIC-adventices). Le premier volet du travail a consisté à étudier la rétention de l’eau dans la couche du sol travaillée dans les 5 systèmes de culture. La rétention de l’eau a été comparée dans des échantillons de sol dont la structure a été soit « conservée », soit « remaniée » afin d’identifier la part de la variabilité liée aux caractéristiques physiques intrinsèques du sol de celle induite par les pratiques culturales. Les résultats ont montré que le sol du système de culture avec suppression totale des herbicides, associant une teneur élevée en argile, une teneur moyenne en C organique et un travail superficiel intensif, présentait les valeurs les plus élevées de rétention de l’eau dans la couche de sol travaillée. Le second volet a porté sur l’étude de la variabilité de la conductivité hydraulique proche de la saturation, K(h), aux échelles de l’année culturale et du profil du sol. Pour cette étude, 3 systèmes PIC-adventices (système de culture en semis direct et systèmes de culture avec travail du sol modéré à intensif) ont été caractérisés pendant 2 ou 3 années culturales consécutives, en considérant 3 profondeurs de sol incluant la couche du sol travaillée et l’horizon sous-jacent. Les résultats n’ont montré aucune variabilité de K(h) à l’échelle verticale. Par contre, ils ont mis en évidence les effets à long terme des systèmes PIC-adventices sur les valeurs de K(h). Enfin, le dernier volet a étudié la dynamique de l’eau dans le sol de 2 systèmes PIC-adventices contrastés (système avec conduite du sol en semis direct et système sans herbicide avec travail du sol intensif) en suivant une approche d’hydraulique agricole et par le biais de la caractérisation in situ du potentiel matriciel de l’eau dans le sol et de la mesure des quantités d’eau collectée au moyen de lysimètres à mèche. L’approche utilisée a permis la description de la dynamique de l’eau du sol pendant la période de drainage, la validation du fonctionnement des lysimètres à mèche et le calcul de la surface de sol équivalente qui contribuait au transfert de l’eau dans ces dispositifs. Ces premiers résultats prometteurs nécessiteront néanmoins d’être validés au cours de prochaines campagnes de mesure. L’ensemble des résultats recueillis constituent une première évaluation du fonctionnement physique et hydrodynamique du sol des systèmes PIC-adventices présents sur le dispositif expérimental. La base de données constituée permettra ultérieurement la poursuite du travail engagé en modélisant le transfert de l’eau, de solutés, de pesticides ou d’autres polluants dans le sol de ces systèmes PIC-adventicesIntegrated weed management (IWM)-based cropping systems are of great interest due to their significant reduction of herbicide inputs by using a complex combination of agricultural techniques. The main objective of our work was to contribute to the environmental dimension of the multi-criteria evaluation of IWM-based cropping systems which were set up since 2000 on the experimental domain of the National Institute for Agronomical Research (INRA) to Bretenière (France). The variability of physical and hydrodynamic soil properties involved in the transfer of water through the vadose zone was studied for the 5 cropping systems present on the experimental site (1 reference cropping system and 4 IWM-based cropping systems). The first section of our study consisted in studying the water retention of the tilled soil layers for the 5 cropping systems. Water retention values were compared between undisturbed and repacked soil samples in order to distinguish the part of the variability due to the intrinsic soil properties from the one induced by the agricultural practices. Our results show that the soil from cropping system without any herbicides, associating high clay content, average organic C content and intensive superficial tillage, may increase soil water retention in the tilled soil layer. The second section carried on the study of the annual and vertical variability of the near-saturated hydraulic conductivity, K(h). For this study, 3 IWM-based cropping systems (no-tilled cropping system and moderate to intensive tilled cropping systems) were characterized during 2 or 3 consecutive years and considering 3 depths including the soil tilled layer and the underlying no-tilled layer. The results showed no vertical variability of K(h). However, they highlighted the long-term effect of IWM-based cropping systems on K(h). Finally, the third section studied the soil water dynamics of 2 contrasted IWM-based cropping systems (no-tilled and zero herbicide cropping systems with intensive tillage) by using ,a hydraulic agricultural approach and by the means of the in situ characterization of soil matric potential and the measure of the amounts of water collected with wick lysimeters. This approach allowed the description of the water dynamics during the drainage season, the validation of the wick lysimeters functioning and the calculation of the surface contributing to water flows collected by the wick lysimeters. These promising results will need to be validated during forthcoming campaigns of measurement. All data collected provided constitute a first evaluation of the soil physical and hydraulic functioning of IWM-based cropping systems present on the experimental site. The established database will allow later the pursuit of work by modeling the water transfer and the transport of solutes, pesticides or other pollutants through the vadose zone of these IWM-based cropping systems
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MOROTE, CARLOS HUGO SOTO. "STABILITY AND DEFORMATION OF SOIL SLOPES UNDER SEISMIC LOAD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9532@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOO comportamento sísmico de taludes tem sido um tópico de grande interesse da engenharia geotécnica nos últimos 40 anos. Durante este período, a prática da engenharia nesta área evoluiu do emprego de técnicas elementares para procedimentos numéricos bastante complexos. A abordagem mais simples é a análise pseudo-estática na qual o carregamento do terremoto é simulado por uma aceleração horizontal estática equivalente atuando na massa de solo deslizante, utilizando-se um procedimento de equilíbrio limite (método das fatias), geralmente conservativo. O parâmetro que descreve o comportamento dinâmico do solo é referido como coeficiente sísmico k, e sua seleção depende fortemente da experiência e normas técnicas locais, porque não há maneira simples e segura de se escolher um valor adequado. O segundo procedimento é conhecido como método de Newmark, que envolve o cálculo de uma aceleração de escoamento, definida como a força inercial necessária para o fator de segurança atingir 1 em uma análise pseudo-estática pelo método de equilíbrio limite. O procedimento então usa os registros de aceleração do terremoto de projeto e o integra duplamente no tempo para calcular os deslocamentos permanentes acumulados. O terceiro método é referido como análise de Makdisi- Seed, que procura definir a estabilidade sísmica do talude em termos de deslocamentos aceitáveis em vez de um fator de segurança tradicional através de uma versão modificada do método de Newmark. Esta técnica apresenta uma maneira racional de calcular uma aceleração de escoamento média, necessária para produzir um valor do coeficiente de segurança do talude igual a 1. Gráficos específicos foram também desenvolvidos para estimativa dos deslocamentos permanentes, tendo sido bastante aplicados em aterros rodoviários, barragens e aterros sanitários. Finalmente, o mais sofisticado método para análise de estabilidade sísmica de taludes é conhecido como análise dinâmica, que normalmente incorpora modelos de elementos finitos e relações tensão x deformação complexas numa tentativa de obter melhores representações para o comportamento mecânico de taludes sob cargas cíclicas Os resultados destas análises podem incluir a história no tempo dos deslocamentos e tensões, bem como das freqüências naturais, efeitos de amortecimento, etc. Este trabalho apresenta uma comparação entre os métodos mencionados anteriormente, analisando o comportamento sísmico dos taludes da estrutura de contenção dos resíduos de lixiviação de minério de urânio, na Bahia, e dos taludes do bota-fora sul da mina de cobre Toquepala, situada no Peru.
The seismic stability of slopes has been a topic of considerable interest in geotechnical engineering for the past 40 years. During that period, the state of practice has moved from simples techniques to more complicated numerical procedures. The simplest approach is the pseudo-static analysis in which the earthquake load is simulated by an equivalent static horizontal acceleration acting on the mass of the landslide, according to a generally conservative limit equilibrium analysis. The ground motion parameter used in a pseudo-static analysis is referred to as the seismic coefficient k, and its selection has relied heavily on engineering judgment and local code requirements because there is no simple method for determining an appropriate value. The second main procedure is known as the Newmark displacement analysis which involves the calculation of the yield acceleration, defined as the inertial force required to cause the static factor of safety to reach 1 from the traditional limit equilibrium slope stability analysis. The procedure then uses a design earthquake strong-motion record which is numerically integrated twice for the amplitude of the acceleration above the yield acceleration to calculate the cumulative displacements. These displacements are then evaluated in light of the slope material properties and the requirements of the proposed development. The third method is referred to as the Makdisi-Seed analysis sought to define seismic embankment stability in terms of acceptable deformation instead of conventional factors of safety, using a modified Newmark analysis. Their method presents a rational means to determine yield acceleration, or the average acceleration required to produce a factor of safety of unity. Design curves were developed to estimate the permanent earthquake- induced deformations of embankments, which have since been applied to sanitary landfill and highway embankments. Finally, the most sophisticated method for seismic slope stability calculations is known as the dynamic analysis, which normally incorporates a finite element model and a rather complex stress-strain behavior for geological materials in an attempt to obtain a better representation of the behavior of soils under cyclic loading. The results of the analysis can include a time history of displacements and stresses, as well as natural frequencies, effects of damping, etc. This work presents a comparison of the results obtained by the aforementioned approaches, considering the seismic behavior of the slopes of an uranium lixiviation pad situated in Bahia, Brazil, and the South embankment of the waste landfill of the Toquepala Mine, Peru.
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Larson, Douglas G. (Douglas Gregory). "A laboratory investigation of load transfer in reinforced soil." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12903.
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Liu, Yunlong. "Interpretation of Load Transfer Mechanism for Piles in Unsaturated Expansive Soils." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38804.
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Water infiltration associated with natural precipitation events or other artificial activities such as pipe leaks in expansive soils significantly influence the engineering properties; namely, coefficient of permeability, shear strength and volume change behavior. For this reason, it is challenging to design or construct geotechnical infrastructure within or with expansive soils. Several billions of dollars losses, world-wide, can be attributed to the repairing, redesigning and retrofitting of infrastructure constructed with or within expansive soils, annually. Piles are widely used as foundations in expansive soils extending conventional design procedures based on the principles of saturated soil mechanics. However, the behavior of piles in unsaturated expansive soils is significantly different from conventional non-expansive saturated soils. Three significant changes arise as water infiltrates into expansive soil around the pile. Firstly, soil volume expansion contributes to ground heave in vertical direction. Secondly, volume expansion restriction leads to development of the lateral swelling pressure resulting in an increment in the lateral earth pressure in the horizontal direction. Thirdly, pile-soil interface shear strength properties change due to variations in water content (matric suction) of the surrounding soil. These three changes are closely related to matric suction variations that arise during the water infiltration process. For this reason, a rational methodology is necessary for the pile load transfer mechanism analysis based on the mechanics of unsaturated soils.
Studies presented in this thesis are directed towards developing simple methods to predict the load transfer mechanism changes of piles in expansive soils upon infiltration. More emphasis is directed towards the prediction of the pile mechanical behavior which includes the pile head load-displacement relationship, the pile axial force (shaft friction) distribution and the pile base resistance using unsaturated mechanical as a tool. The function of matric suction as an independent stress state variable on the mechanical behavior pile is highlighted. More specifically, following studies were conducted:
(i) Previous studies on various factors influencing the load transfer mechanisms of piles in unsaturated expansive soils are summarized and discussed to give a background of current research. More specifically, state-of-the-art reviews are summarized on the application of piles in expansive soils, mobilization of lateral swelling pressure, mobilization of unsaturated pile-soil interface shear strength and methods available for the load transfer analysis of piles in expansive soils.
(ii) Employing unsaturated soil mechanics as a tool, theoretical methods are proposed for estimating the lateral earth pressure variations considering the mobilization of lateral swelling pressure. The proposed methods are verified using two large-scale laboratory studies and two field studies from published literatures.
(iii) The shear displacement method and load transfer curve methods used traditionally for pile load transfer mechanisms analysis for saturated soils were modified to extend their applications for unsaturated expansive soils. The influence of volume change characteristics and unsaturated soil properties on unsaturated expansive soils are considered in these methods. The validation of the modified shear displacement method and modified load transfer curve method were established using a large-scale model test performed in the geotechnical engineering lab of University of Ottawa and a field case study results from the published literature.
(iv) A large-scale model pile infiltration test conducted in a typical expansive soil from Regina in Canada in the geotechnical lab of University of Ottawa is presented and interpreted using the experimental data of volumetric water content suction measurements and shear strength data. The results of the comprehensive experiment studies are also used to validate the proposed modified shear displacement method and modified load transfer curve method achieving reasonable good comparisons.
The proposed modified shear displacement method and modified load transfer curve method are simple and require limited number soil properties including the soil water characteristic curve (SWCC), matric suction profile upon wetting and drying and some soil physical properties. Due to these advantages, they can be easily and conveniently applied in engineering practice for prediction of the mechanical behavior of piles in unsaturated expansive soils, which facilitate practicing engineers to produce sound design of pile foundation in unsaturated expansive soils in a simplistic manner.
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Davison, L. R. "Continuous loading consolidation tests on soils." Thesis, University of the West of England, Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234804.
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Vaziri, Mohsen. "Screw plate testing : experimental and numerical investigations." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/843439/.
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The estimation of the compressibility of normally and overconsolidated granular soils was the main aim of the research. A model screw plate instrument was designed and developed and various plate geometries and plate advancement mechanisms were studied with a view to assessing soil disturbance during installation. Screw plate loading tests were conducted by means of a plate 50 mm in diameter 3 mm thick and 5 mm pitch. All the tests were conducted in a calibration chamber under stress controlled conditions on normally and overconsolidated saturated Leighton Buzzard sand along Ko and isotropic stress paths. Stress path triaxial tests were performed on normally and overconsolidated sand specimens. The stress-strain responses observed from such tests were compared with the pressure-settlement curves obtained from screw plate tests. The CRISP Finite Element Program was utilised to model the embedded plate and the chamber. Stress distributions and induced settlements beneath the plate were studied. Finally the effect of plate rigidity on the distribution of stresses was investigated and the validity of dimensions of the calibration chamber for the purpose of screw plate testing was proven.
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Textor, Nathan S. "Load transfer in reticulated and non-reticulated micropiles from large-scale tests." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5008.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 3, 2008) Includes bibliographical references.
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Constancio, Lucas Amarante. "Capacidade de carga de um modelo de fundação superficial em solo arenoso fofo com reforço de geotêxtil." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258742.
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Orientador: Pérsio Leister de Almeida BarrosDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: Este trabalho visa avaliar o ganho de capacidade de carga de uma fundação superficial em areia fofa, através da inclusão de reforço de material geossintético. Para tanto, propõe-se observar o aumento da capacidade de carga do solo, com uma única camada de reforço em geotêxtil tecido, para uma fundação superficial do tipo sapata corrida. Através de um modelo reduzido que atende os critérios para atingir o estado plano de deformação, avalia-se a capacidade de carga do solo sem reforço, com reforço planar horizontal e faz-se uma nova proposta de disposição geométrica de tal elemento, buscando maior ganho de capacidade de carga e atenuação de deformações. O modelo reduzido é ensaiado no interior de um tanque que permite o acompanhamento das deformações através de sua face translúcida, além da aquisição dos dados de carga aplicada e recalque da fundação. Com a aquisição dos dados, é possível estabelecer comparações entre as diferentes situações analisadas, através da análise dos gráficos de carga-recalque. O trabalho mostra que é possível obter-se um ganho na capacidade de carga com inclusão do reforço e também que é possível chegar a capacidades de carga ainda maiores, apenas readequando a geometria do posicionamento do reforço com uma angulação do geotêxtil. Por fim, este trabalho contribui para a compreensão dos fatores envolvidos na complexa interação entre solo e reforço para fundações apoiadas sobre solos reforçados, campo este, que ainda precisa de refinamento, pesquisa, novas abordagens e contribuições
Abstract: This study aims to evaluate the gain in bearing capacity of a shallow foundation on a soft sand, through the inclusion of geosynthetic reinforcement. For this, the bearing capacity of a soft sandy soil carrying a shallow strip footing, without any reinforcement, and with a single layer of reinforcement of a woven geotextile is observed. Through the use of a reduced model, which satisfy the criteria for reaching a plane strain state, the bearing capacity of the unreinforced soil, the soil reinforced with planar horizontal and the soil reinforced with a new proposed geometric arrangement seeking greater gain of bearing capacity and the attenuation on deformation are evaluated. The reduced model is placed in a tank which allows the monitoring of deformations through its translucent face, and acquisition of applied load and foundation settlement data. After the acquisition of data it is possible to make comparisons between the different situations analyzed by examining the plots of load versus settlement. The results show that it is possible to obtain a gain in capacity with the inclusion of reinforcement and that it is possible to reach even higher bearing capacity just adjusting the geometry of the reinforcement placement, providing an inclination to the geotextile sheet. Finally, this work adds to the understanding of the different factors affecting the complex iteration mechanisms involved in foundations over reinforced soils, a field that still needs refinement and research, new approaches and contributions
Mestrado
Geotecnia
Mestre em Engenharia Civil
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Bullock, Murray S. "Overwinter processes and wind erodibility of clay loam soils in southern Alberta." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60279.pdf.
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Gameda, S. "Quantification, predictability and alleviation of high axle load compaction in Quebec soils." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39818.
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Soil structure and crop response under annual compactive loads of 10 and 18 t/axle and compaction alleviation treatments were assessed in a continuous corn production system. The alleviation treatments consisted of chemical conditioning with a non-ionic surfactant, and subsoiling with narrow-tined and winged implements. Parameters utilized for determining effects on soil structure were bulk density, water retention characteristics and soil profile characteristics. Significant topsoil and subsoil compaction resulted from both loading levels. Crop yield reductions due to compactive loading ranged from 18 to 27% under optimal weather conditions and were as high as 55 to 86% under adverse weather conditions. Soil amendments by chemical conditioning had no beneficial effect on soil structure or crop yields. Inter-row subsoiling with narrow-tined and winged subsoilers was effective in reducing soil compaction and increasing crop yields.Soil bulk density measurements gave good indication of overall compaction to a depth of 0.4 m and correlated well with crop yields, but were unable to locate differences between compactive treatments. Water retention characteristics indicated significant differences between compactive treatments to a depth of 0.6 m. Soil profile characteristics were useful for determining ped type and size as well as rooting depth and gave the best overall assessment of compaction alleviation effects.
Studies were also conducted to develop a method for predicting soil compactibility that would serve to manage soil compaction at the farm level. Preliminary studies focused on the determination of soil material properties for predicting bulk density changes under applied loads. Further investigations were conducted on the variations in constrained modulus, cone index and soil bulk density values under uniaxial loading. A model relating constrained modulus as a function of cone index, bulk density and soil moisture content was developed. Subsequent studies conducted yielded significant relationships between penetration resistance and soil compactibility as indicated by constrained modulus and coefficient of compressibility. Relationships obtained between penetration resistance and parameters of compactive work and bulk density change indicated the feasibility of assessing soil compactibility at the farm level.
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Saha, Chitta Ranjan. "Parametric studies of load transfer mechanism of piles embedded in homogeneous soil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0018/MQ52654.pdf.
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Dapp, Steven Douglas. "Static Lateral Load Testing of Model Piles in Clay Soil Phase 1." DigitalCommons@USU, 2000. https://digitalcommons.usu.edu/etd/4544.
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This research project was done on behalf of the Utah Department of Transportation (UDOT). Model piles were subjected to static lateral loading in homogeneous, undisturbed clay with a known undrained shear strength. The dimensions of length, diameter, height from soil to applied load, and a pile stiffness parameter as was determined by dimensional analysis to be consistent will common full-scale steel pipe piles commonly used by UDOT. Bending moment profiles of the model pile were obtained for Lateral loads using foil type strain gages. Pile head deflection and soil response (p-y curves) were determined from these measured pile moment profiles.
Model pile test results were compared to predictions made by the computer design packages Florida Pier (a 3-D, nonlinear, finite element analysis program written at the University of Florida) and COM624P.
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Huat, Bujang bin Kim. "Simulation of field trial structures." Thesis, University of Manchester, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294076.
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Palmer, Andrew L. "Load Transfer Mechanisms for Piles in Soft Soils." DigitalCommons@USU, 1994. https://digitalcommons.usu.edu/etd/4603.
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The purpose of this thesis is to interpret pile load test data for several instrumented piles to determine the load transfer characteristics of driven piles in soft so ils. Piles develop resistance to axial loads through two different mechanisms, side friction and end bearing. The rate that resistance develops is dependent upon soil type , pile type, and movement of the pile with respect to the soil. This thesis addresses load transfer for driven pipe piles in deep lacustrine deposits along the Wasatch Front area of Utah. The piles used in this study were installed for the support of highway structures in the Salt Lake City area. The information used in this study was obtained from the Utah Department of Transportation. Suggestions for pile capacity prediction are included as part of this study.
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Flury, Markus. "Transport of bromide and chloride in a sandy and a loamy field soil /." [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10185.
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QUISPE, CRISTIAN CHACÓN. "BEHAVIOR OF CLAYEY SOIL STABILIZED WITH MUNICIPAL SOLID WASTE ASHES UNDER STATIC LOAD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=22124@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
A gestão dos Resíduos Sólidos Urbanos (RSU) e seu consequente reaproveitamento ou não é um problema existente no Brasil e no mundo. No Brasil, a produção de energia mediante incineração de RSU ainda está na sua etapa inicial, como por exemplo, com a implantação da Usina Verde no campus da UFRJ, com a consequente produção de subprodutos, como as cinzas volante e de fundo. Este estudo apresenta o comportamento de um solo coluvionar argiloso estabilizado com cinzas de RSU sob carregamento estático, tendo como principal objetivo avaliar a influência destas cinzas misturadas com o solo para possíveis aplicações em obras geotécnicas. Para isso foram realizados ensaios de caracterização física, química e mecânica, como ensaios de compactação Proctor Normal e ensaios triaxiais consolidados isotropicamente drenados (CID), para o solo puro e misturas solo-cinza. Foram avaliadas as influências do teor de cinzas (20 por cento, 30 por cento e 40 por cento de cinza volante e de cinza de fundo), bem como do tempo de cura (30 e 60 dias). Os resultados mostram que todas as misturas solo-cinza apresentam melhores parâmetros de resistência, em comparação do solo puro, onde as misturas solo-cinza volante apresentaram melhores resultados quando comparadas às misturas solo-cinza de fundo. A variação de teor de cinza adicionado ao solo, sem cura, mostra que para maiores teores de cinza volante a coesão diminui e ocorre o contrário com a cinza de fundo. Com relação ao tempo de cura, na maioria dos casos houve melhora do comportamento das misturas solo-cinza em comparação ao obtido sem cura. O teor de cinza (volante ou de fundo), tempo de cura e a tensão de confinamento influenciam na deformação volumétrica das misturas solo-cinza, apresentando menores deformações volumétricas para maiores teores de cinza e maiores tempos de cura. As misturas com 40 por cento de cinza volante e 30 por cento de cinza de fundo apresentaram as melhores características de resistência e poderiam ser utilizadas como estabilizante no solo estudado, cumprindo exigências geotécnicas e ambientais, além de rebaixar os custos de obra e dar um destino mais nobre para as cinzas de RSU.
Management of Municipal Solid Waste (MSW) and its subsequent reuse or not is an existing problem in Brazil and the world. In Brazil, the production of energy through incineration of MSW is still in its initial stage, for example, with the implementation of Usina Verde on campus at UFRJ, with the consequent production of byproducts, such as fly and bottom ashes. This study presents the behavior of a colluvial clayey soil stabilized with ashes from MSW under static load, with the main objective to evaluate the influence of these ashes mixed with the soil for possible applications in geotechnical works. For this characterization were performed physical, chemical and mechanical tests, as Proctor compaction tests Normal isotropically consolidated and drained triaxial (CID) for the pure and soil-ash mixtures. Were evaluated the influence of the ash content (20 per cent, 30 per cent and 40 per cent fly ash and botton ash) and of curing time (30 and 60 days). The results show that all mixtures soil-ash have better shear strength compared to the pure soil, where the soil- fly ash mixtures showed better results compared to mixtures of soil- bottom ash. The variation of the ash content added to the soil, without curing, shows that higher levels of ash the cohesion decrease and the opposite occurs with the bottom ash. Respect to the curing time, in most cases there was as improvement of the behavior of mixtures soil-ash compared to that obtained without curing. The ash content (fly or bottom), curing time and confinement stress influence the volumetric deformation to soil-ash mixtures, showed lower volumetric deformations to higher concentrations of ash and longer curing times. The mixtures with 40 per cent fly ash and 30 per cent bottom ash, showed the best characteristics of strength and could be used as stabilizer in the studied soil, compliance requirements geotechnical and environmental, in addition to lower labor costs and give a nobler destiny for the ashes of MSW.
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Matzke, Jeffrey Alan. "Geophysical investigation of the stone zone and loamy mantle on the Iowan surface." Thesis, The University of Iowa, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1550914.
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The processes that generated the distinctive landscape of the Iowa Erosion Surface (IES) of northeastern Iowa have been debated for over a century. A number of researchers have concluded that the IES experienced a periglacial environment and was underlain by continuous permafrost during the last glacial maximum. Ubiquitous throughout the IES is a stone zone that lies 60-100cm below the surface. Several explanations for the genesis of the stone zone have been proposed, including a lag concentrate, biomantle processes, and cryogenesis. We utilized a combination of coring and trenching, ground penetrating radar and resistivity to investigate the 3D distribution of the stone zone, overlying "pedisediment" and the underlying contact with dense till across a 100m2 area on a typical IES hillslope in east-central Iowa . Our preliminary results indicate that the stone zone occurs in the basal few decimeters of pedisediment that rests uncomformably and abruptly on eroded, dense till. Ice wedge casts extend from the stone zone into the underlying till. The depth of the stone zone below the modern surface increases downslope and the stone zone dissipates and eventually is replaced by relatively thick loamy sand beneath the footslope. These relationships argue against the stone zone being of biogenic origin. The occurrence of ice wedge casts associated with the stone zone and systematic changes in the thickness and texture of the pedisediment suggest to us that stone zone on the IES was formed by a combination of cryogenic and active zone erosive processes during the full glacial period.
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Chauhan, Samir. "Laboratory measurements of load-transfer in geosynthetic reinforced soils." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11202.
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England, Melvin Gerrard. "A pile behaviour model." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311976.
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Stokes, Michael Jeffrey. "Advancements in rapid load test data regression." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001929.
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Abit, Sergio Jr Manacpo. "Evaluation of subsurface solute transport and its contribution to nutrient load in the drainage ditches prior to restoration of a Carolina Bay." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-11152005-183644/.
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Subsurface solute transport is a major mechanism that contributes to the contaminant load in both surface and ground waters. Among these contaminants are plant nutrients that if transported in excessive amounts to surface waters can cause adverse effects on humans and animals, as well as negative impacts on aquatic life. The general objective of this study was to conduct a field evaluation of subsurface solute transport in the capillary fringe (CF) and shallow ground water (SGW) and their contribution to nutrient load in the ditches prior to restoration of a Carolina Bay. Specifically, this study was aimed at evaluating: a) the horizontal flow of bromide (Br-) in the CF and SGW under field conditions, b) the fate of nitrate (NO3-) in the CF and SGW in a sandy field site drained by ditches, and c) the possible contribution of subsurface flow to the increased nutrient load in drainage ditches at a drained Carolina Bay following storm events. The study was conducted in Juniper Bay, a drained Carolina Bay in Robeson County, NC. A solute transport experiment was conducted at a sandy site in the Bay where a solution containing Br- and NO3- was applied into an auger hole dug to about 10 cm above the CF during the time of application. The transport of Br- and NO3- in the CF and SGW was monitored by frequently collecting soil water samples using tension lysimeters installed at depths of 45, 60, 75, 90 and 105 cm at lateral distances of 20, 60, 120, 220 and 320 cm from the auger hole along the general direction of the ground water flow. A representative monitoring site from each of the Bay?s mineral and organic soil areas was also chosen for a year-long monitoring of fluctuations in nutrient concentrations in water samples from the Bay?s main ditch exit as well as from the vadose zone, ground water and lateral ditches. Soil solution from the vadose zone and ground water samples were collected using tension lysimeters installed at 15-cm depth intervals from 15 to 120, and 30 to 180 cm depths at the mineral and organic soil sites, respectively. Ground water samples were collected from three fully perforated wells. Seven piezometers installed at each site also allowed collection of ground water samples from different depth intervals below the water table The direction and magnitude of the subsurface hydraulic gradient at the monitored sites were also determined using the three-point technique. Lateral transport of Br- in the CF was observed in the direction of ground water movement up to 320 cm from the auger hole where solutes were applied. The Br- plume from the unsaturated zone that entered into the CF tended to stay and move horizontally in the CF until it was partially moved into the ground water by the fluctuating WT following rain events. The normalized concentrations (concentration in soil solution/concentration in the applied solution) of both NO3- and Br- in water samples collected from CF were comparable for all distances from the application spot. However, in the groundwater, the normalized concentration of NO3- was substantially lower than the normalized Br- concentrations. We believe the reduction in NO3- concentration in the ground water was due to denitrification. Results from the nutrient monitoring experiment reveal that the sample taken from the main ditch exit following a 5 cm d-1 storm event had higher concentrations of total organic carbon (TOC), phosphates (PO4-P), calcium (Ca) and magnesium (Mg) compared to the average of samples collected during baseflow conditions. The same was also observed for samples collected from the vadose zone especially at depths closer to the soil surface where organic carbon and extractable Ca, Mg and PO4-P contents were higher. Higher concentrations of these solutes in the ditches and vadose zone coincided with observed increase in the magnitude of the groundwater hydraulic gradient. In addition, it was observed that following the storm events, the direction of the ground water hydraulic gradient tended to become more perpendicular to the nearby lateral ditch suggesting that the route taken by the water as it moves in the subsurface towards the ditch is shortened. We believe that the increase in concentration of PO4-P, Ca, Mg and TOC in the soil solution at certain depths in the soil profile coupled with their higher rate of movement in the subsurface towards the ditch following the storm event should have contributed to the increase in concentration of such nutrients in the ditches.
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Linhares, Raquel Mariano. "Uso de reforço em geotêxtil com posicionamento não-planar para fundação superficial em solo arenoso fofo." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258562.
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Orientador: Pérsio Leister de Almeida BarrosDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: No presente trabalho foram realizados ensaios em modelos físicos em escala reduzida de fundação rasa sobre solo arenoso fofo reforçado com geotêxtil tecido, visando avaliar o seu comportamento sob carregamento estático vertical. Propõe-se empregar o reforço numa posição inicial não-planar, semelhante àquela adquirida após deslocamentos de 30% da largura da base da sapata (B). Os efeitos da compactação das camadas superiores ao reforço e a variação de seu comprimento também são investigados. Os ensaios foram divididos em 3 grupos: ensaios sobre areia fofa com compacidade homogênea, ensaios de recarregamento e ensaios sobre areia fofa com camadas superiores compactadas. Os resultados indicam que um aumento do comprimento do reforço planar de 3B para 5B não é justificado do ponto de vista do aumento da capacidade de carga ou da atenuação de deslocamentos, em nenhum dos casos. A pequenos deslocamentos, a modificação do posicionamento inicial do reforço de horizontal para não-planar não se justifica, porém, em maiores deslocamentos há um ganho não desprezível na capacidade de carga. Os ensaios de recarregamento mostraram que a protensão do reforço resultante da compactação do solo melhora a capacidade de carga em 2 vezes e atenua em até 75% os deslocamentos. O posicionamento inicial referente a um deslocamento de 30% de B mostrou-se satisfatório; deslocamentos excedentes não trazem maior eficiência ao conjunto. O esforço de compactação gera ganhos similares na capacidade de carga independente do posicionamento inicial do reforço. A atenuação de deslocamentos pode chegar até a 2,6 vezes se comparada ao mesmo caso reforçado com areia homogênea
Abstract: In the present study, some small-scale model tests of a strip footing foundation on loose sand reinforced with woven geotextile were conducted. The main objective was to investigate the effect of the initial placement geometry of the reinforcement on the foundation response to static vertical loads. A non planar placement geometry similar to the one which results from a vertical displacement of about 30% of the foundation width was adopted. The effects of the top layers compaction and the variation of reinforcement length and initial placement were evaluated. The tests were separated in 3 groups: tests on loose sand with homogeneous compacity, reload tests and tests on loose sand with compacted top layers. Results show that an increase on reinforcement length from 3 to 5 times the footing width is not worth the increase in bearing capacity nor the attenuation of settlements, in none of the several cases studied. At little displacements, the modification of initial reinforcement placement, from horizontal to non-planar, seems not to be justified; although after some displacement there is a gain in the bearing capacity. The reload tests showed that the soil compaction creates a prestressing condition on the reinforcement, which improves the bearing capacity in about 2 times and attenuates the settlements up to 75%. The initial placement in about 30% of footing width displacement has proved to be satisfactory; greater displacements do not generate greater system efficiency. The compaction effort of the upper layers creates an improvement that doesn't depend on the reinforcement initial placement. The displacement attenuation can reach up to 2.6 times if compared with the same reinforced case in homogeneous sand ground
Mestrado
Geotecnia
Mestra em Engenharia Civil
50
Ang, Eng-Chew. "Numerical investigation of load transfer mechanisms in slopes reinforced with piles." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4170.
Full textAbstract:
Thesis (Ph. D.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (November 7, 2006) Vita. Includes bibliographical references.