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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Application of Logistic Regression Model for Slope Instability Prediction in Cuyahoga River Watershed, Ohio, USA

Nandi, A., Shakoor, A. 01 March 2008 (has links)
High incidences of slope movement are observed throughout Cuyahoga River watershed in northeast Ohio, USA. The major type of slope failure involves rotational movement in steep stream walls where erosion of the banks creates over-steepened slopes. The occurrence of landslides in the area depends on a complex interaction of natural as well as human induced factors, including: rock and soil strength, slope geometry, permeability, precipitation, presence of old landslides, proximity to streams and flood-prone areas, land use patterns, excavation of lower slopes and/or increasing the load on upper slopes, alteration of surface and subsurface drainage. These factors were used to evaluate the landslide-induced hazard in Cuyahoga River watershed using logistic regression analysis, and a landslide susceptibility map was produced in ArcGIS. The map classified land into four categories of landslide susceptibility: low, moderate, high, and very high. The susceptibility map was validated using known landslide locations within the watershed area. The landslide susceptibility map produced by the logistic regression model can be efficiently used to monitor potential landslide-related problems, and, in turn, can help to reduce hazards associated with landslides.
132

Sedimentological and Foraminiferal Characterization of a Holocene Island Slope (130-240m), North Jamaica

Nelson, Craig V. 01 May 1986 (has links)
Recent carbonate sediments from (133-236m) on the northern Jamaican island slope are significantly different from shallower reef zones (l-70m) in grain constituents, textural parameters, and foraminiferal assemblages. The island slope sediment is dominated by coral fragments, calcareous algae, Halimeda plates, and foraminiferal tests. The sediment is characteristically poorly-sorted, nearly-symmetrically skewed, and mesokurtic, with a mean grain size in the fine sand range. Mineralogically, the sediment is predominantly aragonite (66%) and high-Mg calcite (22%), with some calcite (8%), and minor amounts of clays and other insoluble minerals (4%). Q-mode cluster analyses of sediment constituents, textural parameters, and foraminiferal species and larger group abundances were utilized in the delineation of shelf and island slope depositional environments. ineffective for such use. Mineralogy proves No significant differences are observed in sedimentological parameters (textures, constituents, and sedimentation rates) between an island slope traverse located below an area with prominant sill reefs and a traverse below an area lacking well-developed sill reefs. It is suggested that the sill reefs have less effect on off-reef transport than was previously believed. Based on the abundance trends of certain sediment grains and the similarity of sediment grains in island slope and deep fore reef/fore reef slope sediment, it is suggested that the deeper reef zones (>30m) are the source of most sediment transported seaward. Foraminiferal abundances show lateral differences between traverses related to input of shallow water (
133

Progression and onset of undercut slope failure observed by surface velocity in physical models subjected to arch action / アーチ作用を受けた法尻掘削破壊進行とその誘因に関する表面速度に着目した物理模型実験

Fang, Kun 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21748号 / 工博第4565号 / 新制||工||1712(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 大津 宏康, 准教授 PIPATPONGSA Thirapong, 教授 三村 衛 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
134

Slope stability assessment through field monitoring

Wei, Yukun January 2018 (has links)
Deterministic methods have been used in geotechnical engineering for a long period, such as slope stability calculations. However, only applying deterministic methods is subjective and imperfect. There is a demand to develop a systematic methodology to link the assessed slope stability and field measurement data, which is also known as inverse analysis and forward calculation. Based on the Nya Slussen project, this thesis includes the development of a methodology, deterministic calculation for 4 cross sections using finite element program Plaxis 2D and probabilistic calculation for one section. Deterministic analyses showed satisfying results for all the studied cross sections since their factors of safety exceeded the minimum requirement. In probabilistic design, three parameters were found to have the most uncertainties through sensitivity analysis (undrained shear strength of clay, Young’s modulus of clay and friction angle of fill). Inverse analysis was done by testing different values of them in Plaxis and to try to match the displacement components provided by field measurement. After finding the best optimization for all the parameters, forward calculation gave a final factor of safety. It is suggested that both of the methods should be utilized together for better assessment.
135

Slope Stability Of Laterite Soil Embankments

Gogo-Abite, Ikiensinma 01 January 2005 (has links)
Embankments are key elements in the infrastructural development of structures such as dams, bridges, and roads. Residual soils are generally used as fills in the construction of embankments in areas were residual soils such as laterite is the dominant soil types. Laterite soils have the characteristics of losing its shear strength with time and in fully saturated conditions and its properties varies from region to region. The soil property is influenced by the chemical composition and the environment. The binding agent iron oxide in such soils changes its composition with time and in the presence of moisture. Sudden failures of embankments founded of laterite soils which were, otherwise, checked and found to be safe with high factor of safety, have been observed. This study is performed to investigate the stability of embankments with sudden loss of strength with time and when it is fully saturated. The research includes an investigation of the properties of laterite soils around the world, with particular emphasis on Nigeria. Initially, information is gathered from different sources about the strength-based properties of such soils. Previous research in Nigeria is used as a basis for obtaining real-world soil data. Next, stability analyses are performed using SLOPE/W with shear strength parameters for total stress (short-term), effective stress (long-term), and fully saturated soil conditions. A probability analysis is conducted for the fully saturated conditions because of the variability in the input parameters. Three slope configurations (1:1, 2:1, and 3:1) are considered. The study revealed that the laterite soils embankments lose most of its stability over time period and in full saturation soil conditions. Both these conditions significantly compromise the strength of the soil and the related stability of slopes. To consolidate all information, a database of the properties of laterite soils in some localities of Nigeria was created on the geographic information system (GIS), in order provide a quick access to information on laterite soils in Nigeria.
136

Variation Of Geotechnical Strength Properties With Age Of Landfills Accepting Biosolids

Pinapati, Kishore 01 January 2006 (has links)
The solid portion of waste disposal, known as Municipal Solid Waste (MSW) can be landfilled. Landfilling has proved to be a safe, sanitary and economical method of disposal. A by-product from wastewater treatment plants called biosolids is sometimes co-disposed along with MSW in landfills. Recent work at the University of Central Florida has focused on the behavior of the mixture of MSW and biosolids. As an increased amount of waste accumulates in these landfills, it creates a new problem – the geotechnical stability of landfills. In current literature, classical geotechnical testing methods have been followed to find the strength properties of these landfill materials. Furthermore, geotechnical methods of slope stability analyses have been employed to determine the stability of landfill slopes. As these materials have a high organic content, their strength properties may potentially change with time because of the decay of the organic materials. In the present work, an attempt is made to monitor the change in the geotechnical strength properties of the landfill materials as a function of time. Direct shear tests used for soil testing, with some modifications, were performed on cured compost samples of MSW mixed with biosolids. Geotechnical strength properties of these cured samples were compared to those of an artificially prepared mixture of MSW and biosolids, from the published literature. In addition, direct shear tests are also performed to find the interface properties of a geonet with the cured samples to check the role of a geonet in reinforcing the landfill slopes. A slope stability analysis software SLOPE/W is used to analyze the stability of the landfills. Cohesion is observed to decrease with time while the friction angle increases with time. Stability (the factor of safety against failure) of landfill slopes increases with time due to increased effective stresses and increased friction angle, as the organic material decays. This may result in additional subsidence but an increase in the effective shear strength with time. Based on the interface test results and subsequent slope stability analyses, it is found that the inclusion of a geonet improves the slope stability of a landfill. This could be a potential benefit to the landfill as reinforcement if properly placed. Based on the slope stability analysis on landfills with different slopes, it is concluded that the slope stability of a landfill is improved by keeping the slopes less steep.
137

An Experimental Study of the Dynamic Behavior of Slickensided Surfaces

Meehan, Christopher Lee 08 February 2006 (has links)
When a clay soil is sheared, clay particles along the shear plane become aligned in the direction of shear, forming "slickensided" surfaces. Slickensided surfaces are often observed along the sliding plane in field landslides. Because the clay particles along a slickensided surface are already aligned in the direction of shear, the available shear resistance is significantly less than that of the surrounding soil. During an earthquake, ground shaking often causes landslide movement. For existing landslides or repaired landslides that contain slickensided rupture surfaces, it is reasonable to expect that the movement will occur along the existing slickensided surfaces, because they are weaker than the surrounding soil. The amount of movement that occurs is controlled by the dynamic resistance that can be mobilized along the slickensided surfaces. The objective of this study was to investigate, through laboratory strength tests and centrifuge model tests, the shearing resistance that can be mobilized on slickensided rupture surfaces in clay slopes during earthquakes. A method was developed for preparing slickensided rupture surfaces in the laboratory, and a series of ring shear tests, direct shear tests, and triaxial tests was conducted to study the static and cyclic shear resistance of slickensided surfaces. Two dynamic centrifuge tests were also performed to study the dynamic shear behavior of slickensided clay slopes. Newmark's method was used to back-calculate cyclic strengths from the centrifuge data. Test results show that the cyclic shear resistance that can be mobilized along slickensided surfaces is higher than the drained shear resistance that is applicable for static loading conditions. These results, coupled with a review of existing literature, provide justification for using cyclic strengths that are at least 20% larger than the drained residual shear strength for analyses of seismic stability of slickensided clay slopes. This represents a departure from the current state of practice, which is to use the drained residual shear strength as a "first-order approximation of the residual strength friction angle under undrained and rapid loading conditions" (Blake et al., 2002). / Ph. D.
138

Folkets Hus Farstanäs / People's House Farstanäs

Mollgren, Emmy January 2021 (has links)
I ett naturreservat intill en camping i utkanten av Järnaområdet skapades en ny typ av Folkets hus. Byggnaden är placerad i sydostlig riktning på toppen av en udde, med ett stort entréplan som starten av huset som sedan klättrar sig ned längs med landskapet mot stranden, där man finner den avslutande badplatsen. Det inrymmer en hosteldel med café och en butik för cykel- och båtuthyrning, samt försäljning av allt som hör friluftsliv till, för att knyta samman platsen och byggnaden med naturreservatet och de motionerare som på olika sätt tar sig till platsen. Här finns även en restaurang, konferenssal, utställning samt öppna gemensamma ytor så som offentliga kontor, mötesrum och ett gemensamt allrum där centrets olika gäster kan möstas. Alla dessa ytor knyts samman av en serie trappor som klättrar med byggnaden ner för berget, med öppna plattformar där man närsomhelst kan kliva av och på byggnaden. Naturreservatets redan befintliga stråk har jobbats in i projektet och passerar genom byggnadens entréplattform och fortsätter vidare från butiksplanet, våningen under. Från byggnaden kommer nya stigar skapas genom besökarnas naturliga rörelse genom och runt alla avsatser. / In a nature reserve next to a campsite on the outskirts of the Järna area, a new type of Folkets hus was created. The building is located in a south-easterly direction on top of a headland, with a large entrance floor as the start of the house which then climbs down along the landscape towards the beach, and ends with a bathing spot. It houses a hostel part with a café and a shop for bicycle- and boat rental, as well as sales of everything that belongs to outdoor life, to connect the place and the building with the nature reserve and the exercisers who pass through the place in different ways. There is also a restaurant, conference hall, exhibition and open common areas such as public offices, meeting rooms and a common living room where the center's various guests can meet. All these surfaces are connected by a series of stairs that climb with the building down the mountain, with open platforms where you can exit and enter the building at any time. The nature reserve's already existing trail have been worked into the project and pass through the building's entrance platform and continue on from the store floor, one floor below. From the building, new paths will be created through the visitors' natural movement through and around all ledges.
139

The Determination and Analysis of Deformations in a Soil Under Dynamic Loading

Krzywicki, Henry 09 1900 (has links)
This Thesis describes a method for determining and analysing the deformations in peat caused by a driven rigid wheel. Markers were placed in the peat sample and radiographs were taken as the wheel travelled over the surface of the peat. An analysis of the data revealed that a unique relationship existed between the positions of the markers and the positions of the wheel. The paths of the principal stress trajectories were determined by a graphical method; from the principal stress trajectories, it was possible to find the surfaces of maximum shear. The purpose of determining these surfaces is to allow the equilibrium of the soil mass to be investigated by the present theories in soil mechanics; it is to draw an analogy to the analysis of slope stability problems. / Thesis / Master of Engineering (ME)
140

The Relationship Between the Foreshore Slope, Grain Size and Wave Height

Lindley, Louise Violet 10 April 1987 (has links)
This research paper was submitted to the Department of Geography in fulfillment of the requirements of Geography 4C6. / This study reports on the relationship between the foreshore slopes, grain size characteristics and the wave height on the Hamilton-Burlington Beach. This beach is a non-tidal, low-energy beach. At five stations along the beach, profiles were taken, sediment samples were collected and the average wave heights determined. The slopes were plotted against the mean grain size, the median grain size and the wave heights. There was no clear relationship between the variables tested. It was determined, however, that there existed three areas along this beach. The first area was he one affected only by the wave energy, the second are was affected by both the wave energy and the grain size characteristics, and the third region was affected by the grain size characteristics. / Thesis / Bachelor of Arts (BA)

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