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Islam, Amjad, Stephen U. Nwokoli, and Tatek Debebe. "Bearing Capacity of I-Joists." Thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-12703.
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This work deals with the bearing capacity of wood based I-joists Finite element models were analyzed to determine the bearing capacity of I-joists, using the finite element software Abaqus CAE. The purpose of this study is to compare the results from the developed FE-models with experimental results, and with a previously proposed design formula. To perform the analyses finite element models were created. The model consists of three parts:, the web (made of shell element), the flanges and steel plates used at the supports and loading points (made of solid elements) To determine the bearing capacity of the I-joist two types of analyses were performed, a linear buckling analysis to check the risk of web buckling and a static (stress) analysis to check the risk of splitting of the flanges. This study shows that the steel plate length, in some cases, has little or no impact on primarily the splitting load. Furthermore, the buckling load decreases as the depth of the beam increases, the influence of the depth being proportional to 1/h2. The depth of the beam has no impact on the risk of splitting of the flange.
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Spronken, John Tristan. "Bearing capacity of tapered piles." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ38643.pdf.
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Pla, Rubio Begoña. "The bearing capacity of Nordic soil." Thesis, KTH, Maskinkonstruktion (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175893.
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Heavy forestry machines have great immediate effect on soil properties. This increases the interest to develop approaches that help understanding better the interaction between the forest machines and the terrain and consequently develop the forwarders to be gentle to the environment. The most predominant indications of soil disturbances caused by harvesting are mainly rutting and soil compaction. It is critical to understand and evaluate these damages to be able to protect the remaining trees and improve their tree growth rate. Comprehending the bearing capacity of the soil and the interaction between tire and soil are the key issues to develop forest machines that preserve the terrain. The first step to accomplish this goal is to compare the rut depth theoretical data from empirical models with the rut depth data from a full scale field test, the models suitable to predict rut depth is descripted. Tree roots reinforce the forest floor and significantly increase the bearing capacity of the soil. The contribution from root layer to the soil bearing capacity depends on the number, diameter, orientation of the roots and their mechanical properties. To improve the root tensile strength model, a root bending and stretching laboratory test has been carry out and compared with FEM-based results. The existing Valmet 860. 3 Adams MBS model is finally used to study the suitability of the model to predict rut depth. A comparison between several existing methods to predict rut depth is also shown.Tunga skogsmaskiner har stor omedelbar effekt på markens egenskaper. Detta ökar intresset för att utveckla strategier som underlättar förståelsen av samverkan mellan skogsmaskiner och terrängen och därmed utveckla framdrivning av dessa maskiner som är skonsam mot miljön. De dominerande indikationerna på markstörningar orsakade av hjulbaserade skogsmaskiner är främst spårbildning och jordkompaktering. Det är viktigt att förstå och utvärdera dessa skador för att kunna skydda de kvarvarande träden och förbättra deras tillväxt. Att förstå markens bärighet och samspelet mellan däck och mark är de viktigaste frågorna för att utveckla skogsmaskiner som skonar terrängen. Det första steget för att uppnå detta mål är att jämföra spårdjup vilka är framtagna med empiriska modeller med data för spårdjup från ett fullskaligt fälttest, där de modeller som lämpar sig för att förutsäga spårdjup är beskrivna. Trädrötter förstärker skogsmarken och ökar avsevärt jordens bärighet. Bidraget från rotlagret till jordens bärförmåga beror på antalet rötter, deras diameter samt rötternas orientering och deras mekaniska egenskaper. För att förbättra modellen för rötternas mekaniska egenskaper har rotböjning och rottöjning studerats i ett laboratorietest och vidare jämförts med FEM-baserade resultat. Den befintliga MBS modellen av skotaren Valmet 860.3 har slutligen används för att studera lämpligheten av modellen för att förutsäga spårdjup. En jämförelse mellan flera olika metoder för att förutsäga spårdjup visas också.
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Ardic, Omer. "Analysis Of Bearing Capacity Using Discrete Element Method." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607866/index.pdf.
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With the developments in computer technology, the numerical methods are used widely in geotechnical engineering. Finite element and finite difference are the most common methods used to simulate the behavior of soil and rock. Although the reliability of these methods are proven in several fields of application over the years, they are not equally satisfactory in every case and require sophisticated constitutive relations to model the discontinuous behavior of geomaterials since they assume the material is continuum or the location of discontinuum is predictable. The Discrete Element Method (DEM) has an intensive advantage to simulate discontinuity. This method is relatively new and still under development, yet it is estimated that it will replace of the continuum methods largely in geomechanics in the near feature.
In this thesis, the theory and background of discrete element method are introduced, and its applicability in bearing capacity calculation of shallow foundations is investigated. The results obtained from discrete element simulation of bearing capacity are compared with finite element analysis and analytical methods. It is concluded that the DEM is a promising numerical analysis method but still have some shortcomings in geomechanical applications.
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Russelli, Consolata. "Probabilistic methods applied to the bearing capacity problem /." Stuttgart : IGS, 2008. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016793817&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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López, Ana Priscilla Paniagua. "Two- and three-dimentional bearing capacity of shallow foundations." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bygg, anlegg og transport, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14406.
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Chen, Yung-Chieh. "Seismic bearing capacity of shallow and deep strip foundation." Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/8665.
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Li, Xudong. "Laboratory studies on the bearing capacity of unsaturated sands." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27705.
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In this thesis, extensive experimental studies were undertaken by conducting more than 250 bearing capacity tests on model footings to investigate the bearing capacity of three compacted (coarse-grained, sub-coarse-grained, and fine-grained) sands under both saturated and unsaturated conditions. These tests were conducted in specially designed equipment which includes two test systems for conducting bearing capacity tests using model footings. The designed equipment system had provisions for soil drainage, soil suction profile set for measuring the variation of matric suction with depth of water table, tensiometer holders, vacuum water pumps and other accessories. Two different soil containers (short container with 300 mm in diameter and 300 mm in height and the tall container with 300 mm in diameter and 700 mm in height) were used in the study. The bearing capacity was determined using four different sizes of square model footings (i.e. 20 mm x 20 mm, 25 mm x 25 mm, 37.5 mm x 37.5 mm, and 50 mm x 50 mm). All the equipment was designed by the author and fabricated in the student workshop at University of Ottawa.
The experimental results demonstrated that the bearing capacity of unsaturated fine-grained sand increases as the matric suction increases. However, experimental studies on coarse-grained sand show that bearing capacity appears to decrease as the matric suction increases. Some practical reasons for such a behavior are explained in the thesis.
Experimental studies have also demonstrated that footing sizes in the range of 20 mm x 20 mm to 150 mm x 150 mm had no significant influence on the bearing capacity of sandy soils. The boundary conditions (i.e., ratio of soil container size to footing size) have some effect on the bearing capacity of sands.
A separate experimental program Saturated compacted silt after settlement offers significant resistance to the applied static loads without undergoing creep, however; bearing capacity reduces significantly when it is subjected to dynamic or cyclic loading conditions.
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Eslami, Abolfazl. "Bearing capacity of piles from cone penetration test data." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq21000.pdf.
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Chung, Young-Jun. "Bearing capacity of cohesionless soil after the dynamic compaction." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364882.
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Tapper, Laith. "Bearing capacity of perforated offshore foundations under combined loading." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:4beb1f5c-24d9-4359-a973-95dda05e550d.
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This thesis presents experimental work and numerical analysis that has been undertaken to assess the bearing capacity of perforated offshore foundations. Perforated foundations may be used to support subsea infrastructure, including as mudmats into which a number of perforations have been made, or as grillages which consist of a series of structurally connected strip footings. Larger gravity base foundations, such as for offshore wind turbines or oil and gas platforms, may adopt a single central perforation. The advantages of using perforated foundations can include reduced material requirements and easier offshore handling as a result of smaller weight and lower hydrodynamic forces during deployment. Limited guidance currently exists for assessing the bearing capacity of these foundation types. Bearing capacity of perforated foundations has been examined in this thesis under conditions of combined vertical, horizontal and moment loading which is typical in offshore settings. Undrained soil conditions have been considered, except for the case of grillages in which drained conditions are often most relevant. Experimental work has included centrifuge testing of ring and square annular foundations on clay, and 1g testing of grillage foundations on sand. Finite element modelling has also been undertaken to assess perforated foundation capacity. A Tresca material subroutine (UMAT) and an adaptive meshing scheme have been developed to improve the accuracy of the finite element analysis carried out. The results showed that perforated foundations can be an efficient foundation solution for accommodating combined loading. As a ratio of their vertical load capacity, perforated foundations may be able to withstand higher moment and horizontal loads compared with unperforated foundations. The experimental and numerical results have been used to develop design expressions that could be employed by practitioners to estimate the vertical and combined load bearing capacity of these foundation types.
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Vimalaraj, Panchalingam. "A simple equation for bearing capacity of a shallow foundation." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1438933.
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Qayyum, Tanvir Iqbal. "Bearing capacity of unreinforced and reinforced soil under rapid loading." Thesis, University of Strathclyde, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286906.
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Wong, Kam Kau. "Shear strength and bearing capacity of reinforced concrete deep beams." Thesis, University of Leeds, 1986. http://etheses.whiterose.ac.uk/450/.
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Reinforced concrete deep beans with small span/depth ratios usually fail by crushing of concrete in the bearing zone above the supports. In order to increase the load carrying capacity of deep beans, bearing strength around the supports should be enhanced. The first part of this study involved the investigation of bearing capacity of plain and reinforced concrete blocks. Effects of edge distance, footing to loading area ratios, heights, base friction and size effect are studied with plain concrete blocks. Bearing capacities of reinforced concrete blocks with different forms, diameter and spacing of reinforcement are also investigated. It is found that interlocking stirrups at small spacing are the most effective form of reinforcement. A failure mechanism for a concrete block in bearing is proposed and found to give the best estimate as compared with other models by different researchers. The second part is concerned with the behaviour of reinforced concrete deep beans with span/depth ratios ranging from 0.7 to 1. 1. These beans were tested under uniformly distributed load at the top. It is found that a shear crack is formed along the line joining the inner edge of the support to the third point at the top level of the bean. The concrete block on the outer side of the crack rotates about the centre of pressure in the compression zone. Shear strength is determined by shear in the compression zone, aggregate interlock of the shear crack and dowel action and the components of forces of reinforcement across the crack. Based on these observations, a model of the failure mechanism in shear is proposed which gives excellent results in comparison with other models proposed.
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Che, Wai Fong. "Axial bearing capacity prediction of driven piles using artificial neural network." Thesis, University of Macau, 2003. http://umaclib3.umac.mo/record=b1445140.
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Michels, Julien [Verfasser]. "Bearing Capacity of Steel Fiber Reinforced Concrete Flat Slabs / Julien Michels." Aachen : Shaker, 2010. http://d-nb.info/1104047403/34.
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Quoc, Van Nguyen. "Numerical modelling of the undrained vertical bearing capacity of shallow foundations." University of Southern Queensland, Faculty of Engineering and Surveying, 2008. http://eprints.usq.edu.au/archive/00006257/.
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[Abstract]The bearing capacity of foundations is a fundamental problem in geotechnical engineering. For all structures placed on a soil foundation, geotechnical engineers must ensure that the soil has sufficient load carrying capacity so that the foundation does not collapse or become unstable under any conceivable loading. The ultimate bearing capacity is the magnitude of bearing pressure at which the supporting ground is expected to fail in shear, i.e. a collapse will take place.During the last fifty years various researchers have proposed approximate techniques to estimate the short term undrained bearing capacity of foundations. The majority of existing theories are not entirely rigorous and contain many underlying assumptions. As a consequence, current design practices include a great deal of empiricism. Throughout recent decades, there has also been a dramatic expansion in numerical techniques and analyses, however, very few rigorous numerical analyses have been performed todetermine the ultimate bearing capacity of undrained soils.In this study, finite element analysis has been used to analyse a range of bearing capacity problems in undrained soil. The numerical models account for a range of variablesincluding footing size, shape, embedment depth, soil layering and undrained bearing capacity of footings on slopes.By using the powerful ability of computers a comprehensive set of solutions have been obtained therefore reducing the uncertainties apparent in previous solutions.
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Kenny, M. J. "The bearing capacity of clay overlain by unreinforced and reinforced sand." Thesis, University of Strathclyde, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382354.
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Al-Karni, Awad Ali. "Seismic settlement and bearing capacity of shallow footings on cohesionless soil." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186284.
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Seismic loading reduces the bearing capacity of soils and large settlement can occur. These effects have not been considered adequately in design codes. In this dissertation, the seismic bearing capacity and settlement of soils have been investigated theoretically and experimentally. The theoretical analysis was developed for a dry c-φ soil, considering the effect of the cohesion, and the vertical and the horizontal acceleration components. The seismic bearing capacity was examined by using the concept of shear fluidization of soil, while the seismic settlement was examined using the sliding block model technique. The theory of the shear fluidization of soil was developed for c-φ soils and extended the original application which was limited to cohesionless soils. The experiments were conducted on dry and saturated cohesionless soil using a shake box designed and constructed during this research. The shake box was designed to subject the soil to simple shear conditions during shaking. Model footings, constructed from lead, were used to study the seismic bearing capacity and settlement of shallow footings. The parameters investigated include the horizontal acceleration, the frequency, the safety factor, the footing width, the footing shape and size, the depth of embedment, and the relative density of the soil. The theoretical and the experimental results showed good agreement. Significant reduction in the bearing capacity of the soil, even at low acceleration (e.g. < 0.3 g) and excessive settlement can occur if the seismic bearing capacity becomes lower than the allowable static bearing capacity. Seismic design procedures are proposed and illustrative examples are used to demonstrate the design procedures.
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Keshta, Mohammed A. "Leaching from High Capacity Arsenic-Bearing Solid Residuals under Landfill Conditions." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/193650.
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Arsenic is a naturally occurring contaminant in ground water. The link between human exposure to elevated levels of arsenic and the increase in cancerous and non-cancerous diseases is well documented. Consequently, arsenic removal from drinking water has been thoroughly investigated.Lowering the maximum contaminant limit of arsenic (from 50 to 10 ppb) will burden small water utilities, who either lack the financial or technical ability to comply. Adsorption onto solid media has been one of the most attractive options for small water utilities (EPA, 2001), but this process generates huge amounts of arsenic bearing solid residuals (ABSRs) complicating further this matter.Numerous studies have suggested that the Toxicity Characteristics Leaching Procedure (TCLP) does not properly reflect the actual leaching behavior of ASBRs under landfills (Ghosh et al., 2004). This work focuses on testing different arsenic iron- oxide and non- iron- based sorbents, likely to be used for arsenic removal, and assessing the long term behavior of these sorbents under landfill conditions. Our results indicate that microbial processes play a major role in the mobilization of As from granular ferric hydroxide (GFH). Long term operation of GFH sorbent showed that Fe (III) was reduced to Fe(II) and As(V) was reduced to As(III) under anaerobic/reducing conditions. Under semi batch landfill simulation experiments, our results show that non iron based media leached arsenic above the Toxicity Characteristics limit (TC) and it was observed that sorbate (As) might leach at a faster rate than the sorbent itself. It is thought that arsenic mobilization from iron-based sorbent occurs mostly due to iron reduction and its subsequent dissolution. However, measured arsenic leaching rates from the sorbents used in this study are comparable with that of the ferric hydroxide media, which indicates that the mechanism of arsenic mobilization might be independent of the possible dissolution of the sorbent. Despite the fact that non- iron based media may have a higher arsenic adsorption capacity, they leach arsenic at a higher rate than iron based media under our simulated landfill conditions.
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Tiwari, Dipak. "BEARING CAPACITY OF SHALLOW FOUNDATION USING GEOGRID REINFORCED DOUBLE LAYERED SOIL." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/772.
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Since the last three decades, several studies have been conducted related to improvement in bearing capacity of pavements, embankments, and shallow foundations resting on geosynthetic reinforced soil. Most of the work has been carried out on single layer soil e.g., sand or clay layer only. Very few studies are available on a double layer soil system; but no study is available on the local soil of Carbondale, Illinois. The present study investigates the physical and engineering properties of a local soil and commonly available sand and improvement in the bearing capacity of a local soil for a rectangular footing by replacing top of the local soil with sand layer and placing geogrids at different depths. Seven tests on the model footing were performed to establish the load versus settlement curves of unreinforced and reinforced soil supporting a rectangular foundation. The improvement in bearing capacity is compared with the bearing capacity of the local soil and double layer unreinforced soil system. The test results focus on the improvement in bearing capacity of local soil and double layer unreinforced soil system in non-dimensional form i.e., BCR (Bearing Capacity Ratio). The results obtained from the present study show that bearing capacity increases significantly with the increasing number of geogrid layers. The bearing capacity for double layer soil increases, by placing three inch sand layer at the top of local soil, was not significant. The bearing capacity of the local soil increased at an average of 7% with three inches sand layer. The bearing capacity for the double layer soil increases with an average of 16.67% using one geogrid layer at interface of soils (i.e., local soil and sand) with u/B equal to 0.67. The bearing capacity for the double layer soil increases with an average of 33.33% while using one geogrid in middle of sand layer having u/B equal to 0.33. The improvement in bearing capacity for double layer soil maintaining u/B equal to 0.33 and h/B equal to 0.33; for two, three and four number geogrid layer were 44.44%, 61.11%, 72.22%, respectively. The results obtained from this research work may be useful for the specific condition or similar type of soil available anywhere to improve the bearing capacity of soil for foundation and pavement design.
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Tsukamoto, Yoshimichi. "Drum centrifuge tests of three-leg jack-ups on sand." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360636.
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Sun, Rui. "Bearing capacity and settlement behavior of unsaturated soils from model footing tests." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28533.
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A series of model footing tests were conducted to determine the bearing capacity and settlement behaviour of four different soils of which the first two were coarse-grained soils (Le. Filtration sand and Quarry sand) and the remainder two were fine-grained soils (i.e. Sil-co-sil 106 and Mil-u-sil 30) using four different sizes of model footings (Le. 20 mm x 20 mm, 37 mm x 37 mm, 41.75 mm in diameter, and 50 mm x 50 mm) over a suction range of 0 to 8 kPa. This range of matric suction 0 to 8 kPa extends over the boundary effect, transition and residual stages (Vanapalli et al. 1999) for the two coarse-grained soils (Le. Filtration sand and Quarry sand). A soil container which is 300 mm in diameter and 700 mm in height has been used in the experiment. The targeted matric suction values in the soils were achieved by controlling the level of water table in the soil container and confirmed using Tensiometers installed in the soil at different depths.
The experimental results demonstrated that: 1) The variation of bearing capacity of coarse-grained soils (Le. Filtration sand and Quarry sand) with respect to matric suction was nonlinear in nature. The bearing capacity increases up to the residual suction value and then decreases with further increase in matric suction values. The trends for settlement are however opposite; the settlement decreases up to residual suction value and gradually start increasing along with an increase in the matric suction. 2) For the unsaturated fine-grained soils (Le. Sil-co-sil 106 and Min-u-sil 30), bearing capacity increases and settlement decreases as the matric suction increases because the suction range (Le. 0 to 8 kPa) is in the boundary effect zone. In other words, the suction range in the boundary effect zone is lower than the air-entry value (i.e. saturation zone). More detailed discussions are offered with respect to the bearing capacity and settlement behaviour of unsaturated soils including the influence of footing size on the bearing capacity and settlement results. In addition, these test results were used to verify the semi-empirical models proposed by Vanapalli and Mohamed (2007) and Oh et al. (2009) for predicting the bearing capacity and settlement behaviour of unsaturated soils, respectively.
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Oloo, Simon Yamo. "A bearing capacity approach to the design of low-volume traffic roads." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1994. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ32809.pdf.
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Meng, Qiuhong. "Bearing capacity failure envelopes of foundations with skirts subjected to combined loading." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bygg, anlegg og transport, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23367.
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The bearing capacity of the foundation is reduced in combination with horizontal loads and moments, and can be further reduced when torsion moment is applied. Therefore, torsion moment must be taken into account when calculating the loading capacity. This is particularly relevant for offshore foundations (underwater structures), since torsion is often of considerable size.The aim of this thesis is to make a numerical study of a rectangular mudmat foundation subjected to vertical loading, horizontal loading and torsion moment. The numerical calculations were mainly calculated by the finite element program PLAXIS 3D. Meanwhile, hand calculations of bearing capacities with Janbu and Davis & Booker methods are also carried out for comparison. The numerical studies were limited to undrained loading condition, where the undrained shear strength increases linearly with depth for a rectangular mudmat foundation; a) with outer skirts only b) with both outer and inner skirtsVertical and horizontal bearing capacities of mudmat foundation from finite element program PLAXIS 3D correspond well with the hand calculation results by Janbu method. However, the vertical bearing capacities from PLAXIS 3D are slightly higher than Janbu method, with a differencial value of 460kN(Model 1) and 80 kN(Model 2), corresponding to a differencial of 6% and 1%, respectively. It may have several explanations:?The results of finite element programs is dependent on network element and element type. Theoretically, the analyses of model with more fine meshes and smaller average element size would generate more accurate results. ?PLAXIS 3D bulids a real 3-dimensional model, taking into consideration the 3D effections. However, Janbu method is based on the plane strain. However, torsional bearing capacity from PLAXIS 3D is almost twice the value determined from hand calculations, which may because of the conservative calculation method or some possible parametrical errors in PLAXIS 3D. By intergrating the FEM analyses package PLAXIS 3D with the Swipe test procedure of loading, the failure envelopes of mudmat foundation and approximating expressions are investigated. Through numerical computations and comparative analyses based on FEM, the two-dimensional failure envelopes of mudmat foundation are established by using proposed method to evaluate the stability of foundation under combined loadings. These results could be utilized to provide vital reference for the design and construction of mudmat foundation.
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Rica, Shilton [Verfasser]. "Improved Design Methods for the Bearing Capacity of Foundation Piles / Shilton Rica." Düren : Shaker, 2019. http://d-nb.info/120221875X/34.
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AVIZ, LUCIANA BARROS DE MIRANDA. "EVALUATION OF THE BEARING CAPACITY OF PILES BY THEORETICAL AND EMPIRICAL APPROACHES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9014@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORA fundação em estaxa é uma das alternativas mais antigas de suporte de estruturas,mas seu projeto ainda é um desfio para engenharia geotécnica, sendo muito em pricípios empíricos. As estacas são elementos esbeltos de grande comprimento relativo, gerlamente utilizadas quando os solos que compõem as camadas mais superficiais do terreno não são suficientemente resistentes para suportar as cargas da superestrutura. A capacidade de suporte de estacas pode ser estimada através de métodos teóricos, semi-empíricos. Para aplicação de um método teórico é necessário o conhecimento mais detalhado da geometria do problema, das propriedades tensão x defromação x resistência dos solos, das características da interface solo-estaca,etc., enquanto que para os métodos semiempíricos a aplicação é geralmenta feita com base em resultados de ensaios de campo. As formulaçõessemi-empíricas são as mais usuais na prática da engenharia para o cálculo da capacidade de suporte de estacas visto que os métodos teóricos, à exceção de grandes projetos, têm sua aplicação ainda restrita. Na prática brasileira,os projetos de fundações são elaborados frequentemente com base em resultados de ensaio SPT, sendo os dois métodos mais utilizados para a obtenção da capacidade de carga de estacas os métodos propostos por Aoki e Velloso (1975) e Décourt e Quaresma (1978, 1982). O objetivo deste trabalho consiste em comparar algumas das metodologias correntemente utilizadas na previsão da capacidade de suporte de estacas sob carregamento axial com as previsões obtidas em análises teóricaspelo método dos elementos finitos, através da utilização do programa Plaxis v. 8.
Pile is one of the oldest alternatives of support of structures but its designis still considered a challenge for the ground engineering,being based on empirical principles. Piles are slender elements of great relative length, generally used when soils that compose the most superficial layers of the soil profile are not sufficiently resistant to support the loads from superstructure. The bearing capacity of piles can be estimated by empirical and theoretical approaches. For application of a theoretical approach a more detailed knowledge is necessary about the geometry of the problem, the tension x deformation x resistence soil satate, interface soil-pile characteristics and others, while for empirica approaches the application is generally done on the basis of field test results. The empirical formulations are the most usual in the practice of the engineering for the calculation of the bearing capacity of piles since theoretical approaches have iots application restricted. In brazilian engineering practice, the projects of foundations are elaborated frequently on the basis of SPT test results, being the two approachesd more utilized proposed by Aoki and Velloso (1975) and Décourt and Quaresma (1978, 1982). The objective of this work is compare some of the methodologies currently utilized to obtain the bearing capacity of the piles under axial loading with the results obtained in theoretical analysis by finite element approach, using Plaxis verion 8.0 software.
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Курочкіна, Вікторія Семенівна, Виктория Семеновна Курочкина, Viktoriia Semenivna Kurochkina, and K. V. Levchenko. "Determination of bearing capacity of wooden elements under different types of deformation." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/13464.
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Huang, Che-Chun, and 黃哲君. "Bearing capacity of layered soils." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/28596200074283506287.
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碩士國立中央大學
土木工程學系
86
In the coastal areas of Taiwan, soft clays are deposited extensively at relatively shallow levels in the subsoil profile. Large structures constructed on soft clay are usually founded in stiff or dense thick layers with large bearing capacities. When such good bearing layer does not exist at a shallow level, an evaluation of possibility of a relatively thin dense sand occurring at a shallow level being used as a bearing layer might be considered in the design of the foundation for a structure. Therefore, the bearing capacity of a thin layer of sand underlain by a weak clay layer is a significant subject of this thesis. Since centrifuge testing provides nearly identical stress level in a model to that in the prototype, results of centrifuge tests are more realistic than those of small scaled 1g tests. A series of centrifuge model tests on the homogeneous soils and on the sand overlying clay was conducted to investigate their bearing capacity. Several theoretical methods had been proposed to calculate the bearing capacity of the sand overlying clay, such as: (1) load spreading method (Terzaghi & Peck,1948), (2)limit equilibrium method (Hanna & Meyerhof,1980), (3)kinematic approach of limit analysis (Michalowski,1995), (4)FLAC (Fast Lagrangian Analysis of Con-tinua). The test results of centrifuge model on uniform soil formation are close to the previous theories. Test results of layered soils reveal that the bearing capacity increases with increasing sand thickness-footing width ratio until it reaches that of uniform sand, which can be considered as the upper limit of the bearing capacity of the layered soils. It is also found that limit equilibrium method proposed by Hanna & Meyerhof(1980) and FLAC approach to the result of tests, but the bearing capacity calculated by these methods are smaller than test result. Integration test results and parameter study of theoretical solutions, it reveals that the critical sand thickness-footing width ratio is in the range of 2~4 when the undrained shear stress of clay is within 20~50kPa. In this paper, an alternative method was proposed and verified the validity by former solutions.
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Liang, Zhi Ren, and 梁至仁. "Bearing Capacity of Layered Formations." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/82932940058794519559.
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碩士國立中央大學
土木工程研究所
87
Under the natural condition, the ground usually sedimented in layered formation. In layered formations, when the depth of the upper layer is relatively large than the width of the foundation, the bearing capacity can be evaluated by the strength characteristic of the upper layer. However, when the upper layer is not deep enough, which is relative to the width of the foundation, or the effect ranges to two different kinds of soil layers, we''ll have to make some corrections to evaluate the bearing capacity of the layered formations. This thesis continues the topic of thin layer sand underlying weak clay layer. Besides a strip footing on layered formation, instances clay overlying sandstone and sandstone overlying clay, this thesis deals with the bearing capacity of clay and sandstone. The topic of bearing capacity has been studied through experiments and numerical analyses (finite difference methods, FLAC program). A series of the model tests was performed with the usage of a rigid footing to approximate natural condition. In another aspect, we can also observe the failure modes of foundation. The test results will be compared with numerical analyses. The test results of clay and clay overlying sandstone are close to the FLAC analyses. Although the model test results of sandstone are different from the most of the theoretical methods, they are quiet close to upper bounds method (Chen and Drucker (1969)), plasticity equilibrium methods (Ladanyi (1968), Sowers (1979), Pells (1980), Wyllie (1992)) may be appropriate. The empirical method of Satyanarayana and Garg (1980) has a more accurate prediction of the results of sandstone overlying clay. This thesis has been studied through parametric study and the results have been charted. For practice purpose, the bearing capacity of rock overlying clay can be easily evaluated by the strength characteristic of the upper layer and use design chart to get the bearing capacity factor .
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Ming-Yee, Liang, and 梁明義. "Seismic Bearing Capacity of Soils." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/70664055342424692182.
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碩士淡江大學
土木工程研究所
83
This paper computes the seismic bearing capacity factors of shallow foundations. The method adopted in this study was based on the Prandtl-Terzaghi''s failure mode and a perfect plastic Coulomb material. Rankine''s method for calculation of passive thrust was utilized in this study. The bearing capacity fctors NcE, NqE, and NrE of shallow foundations as well as bearing stress qult under seismic load were computated and tabulated. Defining a reduction ratio, ec(q,r), as the bearing capacity factors under seusmic load, Nc(q,r)E, and the same factors without the seismic load, Nc(q,r)S ;then, after analyses, ec and eq are very close to the same ratio extracting from the literature, while the er is somewhat smaller. This indicates the current method is conservative when compared with other solotions.
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Ip, Kai Wing. "Bearing capacity for foundation near slope." Thesis, 2005. http://spectrum.library.concordia.ca/8784/1/MR14249.pdf.
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The bearing capacity of the foundation is a primary concern in the field of foundation engineering. The self weight of the structure and the applied loads are transferred to the soil safely and economically. The load at which the shear failure of the soil occurs is called the ultimate bearing capacity of the foundation. Quite often, structures are built on or near a slope. This is due to land limitation, such as for bridges or for architectural purposes. The ultimate bearing capacity of the foundations for these buildings is significantly affected by the presence of the slope. Design of foundations under these conditions is complex and the information available in the literature is limited. A numerical model was developed to simulate the case of strip foundation near slope, using the finite element technique together with the program "PLAXIS". The parameters believed to govern this behavior were examined individually to determine their effect on the ultimate bearing capacity of a strip footing. The superposition method was used in the analyses to calculate the bearing capacity factors, N c , N q , and N Þ , independently. The results produced by the present numerical model were compared with the available experimental data. An analytical model was also developed for the problem stated to predict the ultimate bearing capacity of a strip footing. Design theory, design procedure and design charts are presented for practical use
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Tasi, Charng-Yang, and 蔡長洋. "Seismic Bearing Capacity of Shallow Foundations." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/14096947360631578551.
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碩士淡江大學
土木工程學系
87
This paper computes the seismic bearing capacity coefficients of shallow foundations. The method adopted in this study was based on the Terzaghi''s failure mode and limit equilibrium concept. The seismic horizontal and vertical forces are considered in this study. The study assumed two failure surfaces to calculate the seismic bearing capacity coefficients, one is a composite surface composed of a logarithmic spiral and a slip line, another is a logarithmic spiral. The computed bearing capacity coefficients from different failure surface have similar data, and the results from this study compare favorably with the results from literature. The strength mobilization factor decrease slower if the angle of friction is smaller. The strength mobilization factor effects more on the horizontal seismic coefficient kh than the vertical seismic coefficient kv. The seismic coefficients had more effect on unit weight than vertical surcharge and cohesion.
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Yu, Hsing-Yun, and 游欣運. "Inclined Bearing Capacity of Shallow Foundation." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/29521479766462762870.
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碩士淡江大學
土木工程研究所
81
This research attempts to establish a new analytical method to calculate the bearing capacity factors No, Nq and Nr of shallow foundations under inclined loads and the ultimate bearing capacity quit .This method is based on Terzaqhi's failure mechanism(assuming the failure surface under a shallow foundation is a combination of a logarthmic spiral curve and a straight line). The Rankine's theory of passive earth pressure , and the method of moment equili-brium are utilized in the limited equilbrium analysis. The results show that, in the case of vertical loads, the values of the bearing capacity factors Nc, Nq obtained by this method is approximately the same as of Terzaghi(1943), Prakash and Saran (1971), Saran(1971), Narita and Yamaguchi(1989), and Saran and Agarwal(1991); howrvrt, they are larger than that of Caquot-Kerisel(1949), Meyerhof(1951), Sokolovski(1965) and Chen(1975). As far as the Nr is concerned, the values are similar to that of prakash and Saran(1971) but smaller than that of Saran(1971), Chen(1975), Narita and Yamaguchi(1989), and saran and Agarwal(1991). In the case of strip foundation under inclined loads, the theoretical values agree fairly well with Meyerhof's experimental values(1953, 1980, 1981). And when compared with all the experimen-tal data from literature, the theoretical values of the ultimate bearing capacity of anyfoundation using a modified Terzaghi's shape factors also agree approximately Meyerhof's laboratory data.
35
Wang, I.-Shi, and 王乙翕. "Bearing Capacity of Layered Rock Mass." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/78432967006388537578.
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碩士國立中央大學
土木工程研究所
88
In this thesis, foundation tests carried out through reduced scale models, the layered samples used of bearing capacity tests are prepared in methods and techniques used by predecessors. This thesis investigates the bearing capacity of shallow strip footing and failure models of layered stratum by changing different geological condition. It could be comprehended that the behaviors of shallow strip footing overlying stratum in different geological conditions through numerical analysis and model tests. According to the results of the sandstone and shale bearing capacity tests, it could be observed that test results were different from the result of methods proposed by Hill (1950), Chen (1975) and Chen & Drucker (1969), and results of theoretical methods proposed by Bell (1915), Sower (1979), Wyllie (1992) were closed to test results. The limit equilibrium method of Meyerhof & Hanna (1980) had more accurate prediction of the result of sandstone overlying shale. As to geological condition of shale overlaying sandstone, the empirical method proposed by Myslivec & Kysela (1978) was more accurate at capacity forecast. In this paper, an alternative method was proposed and verified the validity by former solutions.
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Srivatsan, K. R., and Satyabrata Behera. "Bearing capacity of model footings on sand." Thesis, 2007. http://ethesis.nitrkl.ac.in/4161/1/Bearing_Capacity_of_Model_Footings_on_Sand.pdf.
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Soil mechanics engineering is one of most important aspects of civil engineering involving the study of soil , its behaviour and application as an engineering material.good soil engineering embodies the use of the best practices in exploration,testing ,design and construction control,in addition to the basic idealized theories. with increasing load on soil due to construction of multi storeyed buildings there is a need to construct footing by conducting a test of their model in laboratory on the soil over which the foundation is to be laid. Sand is one of the soils over which foundations are laid ,so it is necessary to conduct experiments by placing different model footings over sand and find out their ultimate bearing capacity and based on these values ,it can be incorporated on to the field and foundations can be laid. Square footings of different sizes are taken and model testing of these footings are conducted and the ultimate bearing capacity of different footings are found and on the basis of these values foundations are laid on sandy soils .these values can also be compared with theoretical analysis of Terzaghi and Meyerhof ‘s to check out the difference in values of ultimate bearing capacity between a theoretical and practical analysis.
37
Wang, Cheng-Guang, and 王程廣. "Preliminary Study of Bearing Capacity of Shallow Foundation on Reinforced SoilPreliminary Study of Bearing Capacity of Shallow Foundation on Reinforced SoilPreliminary Study of Bearing Capacity of Shallow Foundation on Reinforced Soil." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/74500852488759345197.
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碩士國立宜蘭大學
土木工程學系碩士班
95
Adding geosynthetics into soil has been widely used for Geotechnical Engineering for a long time;however, the interface between soil and geosynthetics still contains a lot of unknowns, which we need to study moreto have better understanding. Langyang Plain contains weak soil with high proportion of fine particulates. Typical problems such as insufficient bearing capacity and excessive settlement always happen when shallow foundation constructed. Thus, the original idea of this proposal comes to mind - utilizing geosynthetics to improve the bearing capacity of shallow foundation on weak soil. First, this research employs the theory developed by Terzaghi for the bearing capacity of shallow foundation. The proposed bearing capacity equation of reinforced shallow foundation considers tension, shear, and pull out failures, which lead to different consequences of bearing capacity. The reinforced soils are sand and clay. In this research, it is found that to reinforce in clayey soil can get better effect than in sandy soil. In addition, reinforced depth is lesser in small friction angle soil than big friction angle soil. In the laboratory, two kinds of soils (sand and clay) are used for the bearing capacity test. The testing results are recorded (both the bearing capacity and the settlement) to compare the influence between reinforced soil and non-reinforced(??) soil. It is found that to reinforce in clay leads to a better result than in sand. The field bearing capacity test, which use geosynthetics on the subgrade of road, comes out a remarkable result of bearing 8 tons by weight. In this research, we also simulate the laboratory test and field test by PLAXIS finite element program. PLAXIS is used to model the laboratory test with two different soils (clay and sand) first. After that, the PLAXIS is used again to simulate the field test for different backfill depth. reinforcing in the clayey soil has a better result than in the sandy soil. The simulated result of reinforced field test shows that the required depth of backfill material is 50cm, which is also similar to field test results. Parametric study shows that the effect of layer number is important for bearing capacity and settlement control. On ther other hand, the lesser depth of reinforcement layer comes out lesser amount of settlement. Besides, the effect of reinforcement depth is more obvious than of layer number on settlement control. This research verifies that reinforced shallow foundation can provide higher bearing capacity and smaller settlement??. In addition, it is also found that reinforcing on weak soil can provide better effect of bearing capacity than on strong soil. Thus, geosynthetics is suitable for solving the problem of insufficient bearing capacity of shallow foundation on weak soil.
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WANG, MENG-YI, and 王孟熙. "Bearing capacity of shallow foundation adjacent to slope." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/82905615610397023732.
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Lin, Chung Ho, and 林忠和. "Uplift Bearing Capacity of Belled Piles in Sand." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/91865482466224533298.
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Zeng, Hao-Yuan, and 曾浩淵. "Study of Ultimate Bearing Capacity on Layered Soils." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/95762880946994791996.
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碩士義守大學
土木與生態工程學系
104
Two of the most important design items in the foundation design of structure are ultimate bearing capacity and settlement analysis. The theory for ultimate bearing capacity in homogenious soils is very clear. However, the ultimate bearing capacity theory in the layered soils has not been to a definite conclusion. As a consequence, an investigating and discussing the research. More research effort could be entered in this research is the ultimate bearing capacity of the layered soils. Finite to obtain the ultimate bearing capacity for varions kinds of layered soils. In this research, the main analytical method is The Mohr-Coulomb model in the PLAXIS software. First, the ultimate bearing capacity for single sand and clay was studied respectively. Second, single sand was categorised into loose sand (30°~35°) and dense sand (36°~40°) by different φ of sand. On the contrary, caly was catedorised into soft clay (30 kN/m2~50 kN/m2) and stiff clay (60 kN/m2~150 kN/m2) by different C of clay. Finally, the respective ultimate bearing capacity of layered sand and clay were obtained from the analysis of interlayer soils by the PLAXIS software. In this reserch, interlayer soils were with different stratum thickness, undrained shear strength and friction angle etc. Consequently, the ultimate bearing capacity for layered soils could be obtained in terms of ultimate bearing capacity of single soils respectively. As a result, we can reach the complete understanding for ultimate bearing capacity of layered soils.
41
Kai-MingChen and 陳凱銘. "Bearing Capacity of Flexible, Rigid and Composite Pavements." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g9c43n.
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GUPTA, NEERAJ. "BEARING CAPACITY OF SHALLOW FOUNDATIONS ON JOINTED ROCK." Thesis, 2017. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16144.
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Rock is a very different engineering material and the process of designing a structure in a rock mass is a very complex problem. The distribution of stresses in the rock mass is equally important as the applied loads. Therefore measurement and judgment both are important while determining the material strength. The behavior of jointed rock mass depends upon many like joint frequency, location of joints, joint orientation, infill material, joint strength etc. The present study aims at studying the variation of bearing capacity of shallow foundation resting over a jointed rock mass through model study. As the process of determining in situ strength of a jointed rock mass is very expensive and difficult, many researchers have performed model studies to predict the strength behavior. The important factors on which strength of a rock mass depends are type of rock, bedding planes, condition of initial stress, presence of joints and cracks, nature of joint surface and the presence of infill material between the bedding planes.
Rocks are not found in intact state anywhere in the world, they essentially have faults and fissures in them which make it an anisotropic medium. These discontinuities like fissures, cracks, joint, bedding plane and faults make a rock weaker and more prone to deformations. In the case of important structures like a dam, leakage of water can take place due to this which can lead to loss of energy and erosion of the dam.
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Farah, Carlos Abou. "Ultimate bearing capacity of shallow foundations of layered soils." Thesis, 2004. http://spectrum.library.concordia.ca/8214/1/MQ94684.pdf.
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The ultimate bearing capacity of shallow foundations subjected to axial vertical loads and resting on soil consisting of two layers has been investigated for the case of strong cohesionless soil overlying weak deposit. In the literature, several theories can be found using simplified failure mechanisms together with a reduced level of the shear strength mobilization on the assumed punching shear zone. It can be reported that large discrepancies between the measured and the predicted values of the ultimate bearing capacities were observed. In this thesis, stress analysis was performed on the actual failure planes observed in the laboratory. In this analysis, full mobilization of the shear strength on the failure planes was considered. New bearing capacity equation was derived as a function of the properties of the upper and lower soil layers, the thickness of the upper layer, the footing depth/width ratio and the angle of the failure surfaces with respect to the vertical. The available experimental data in the literature were used to validate the proposed theory. A design procedure is presented for practicing use.
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Yo, Tze-Young, and 游子揚. "The Ultimate Bearing Capacity Analysis of Composite Ground Structure." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/97291249651154561717.
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碩士國立中央大學
土木工程學系
86
The formation of composite ground is owing to the implant of reinforcing columns into the weak soil layer. In order to ensure the effect of improvement, the ultimate bearing capacity of composite ground should be estimated. Traditionally the ultimate equilibrium method which presumes a failure surface in the critical state and calculates the equilibrium loading is applied on the problem of bearing capacity. However, the failure surface in the critical state is not concluded yet. Therefore the purpose of this paper is to investigate the ultimate bearing capacity by numerical approach. This paper tries to evaluate the influence of soil parameters on the ultimate bearing capacity under the situation considering gravity and to calculate the equivalent material parameters applying the concept of homogenization, then proposes a design chart of the bearing capacity of composite ground using the equivalent material parameters.
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Kuo, Ming-Wei, and 郭明瑋. "Numerical Analysis on Bearing Capacity of Foundation over Slope." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/34436492102448187416.
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碩士國立中央大學
土木工程研究所
92
In this study, FLAC is applied to numerically simulate the behavior of foundation bearing mechanism over horizontal ground and slope. The effect of reduced bearing capacity due to slope is analyzed with slope angles of 10°, 20°, and 30°. Design chart with bearing capacity factors and reducing factor for slope is introduced for applications. The concept of reducing factor is to normalize the bearing capacity factors for horizontal ground with those for slope. The parameters for numerical analysis are: height and slope angle for slopes; position and embedded depth for foundations; friction angle, dilation angle and cohesion for soil material properties. Combinations of parameters under different slope angles are studied to evaluate the effect of reducing factor. When a foundation is placed on the edge of a slope, bearing capacity decreases with slope height increases till critical height (Hcr) is reached. Under this circumstance, the effect of reduced bearing capacity due to slope is maximized and the bearing capacity retains a constant no matter how the height of slope increases beyond Hcr . For the effect of foundation relative position, the reducing factors, αγs, αcs and αqs increase with the increasing of distance between edge of a slope and foundation . The critical distance, beyond which the slope effect no longer exists, increases with the increasing of friction angle and slope angle. Above relationships are mainly affected by slope angle and friction angle, but not obvious by dilation angle.
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Lin, Jin-Rong, and 林進榮. "The Bearing Capacity of Shallow Foundations under Eccentric Loads." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/50281016966398923814.
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碩士淡江大學
土木工程研究所
82
This paper utilizes the Prandtl-Terzaghi mode for calculation of the bearing capacity of shallow foundation under an eccentric load. The fan-shaped free body for stress analysis consists of two lines and part of a logarithmic spiral. Rankine''s state of stress is utilized in the analysis. The calculated bearing capacity factors Nc,Nq,Nr are tabulated for quick reference. Result shows that the bearing capacity factors for vertical concentric loads are comparable with respective factors from literature when a rough base is assumed. When a shallow foundation is subjected to a eccentric load, the calcutated bearing capacity compare favorably with Meyerhof''s and Saran and Prakash''s test results , but larger differences are observed when compared with Purkayastha and Char''s test result.
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Yo-ChengHuang and 黃佑承. "Prediction of bearing capacity of reinforced saturated horizontal grounds." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/71234540367172493992.
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碩士國立成功大學
土木工程學系
103
In 1960’s, French engineer Henri Vidal introduced the idea of reinforced earth. After decades of studies and implementation the concept of reinforced earth is now successfully applied in wide variety of soil structures, including foundations and soil retaining walls. The principle of reinforced earth is to introduce reinforcing material to provide additional constraining forces in soils. Using the interaction between soil and reinforced material, the stress bear by soil is transferred to the reinforcing material to prevent the soil body from deforming, thus increase the strength and ductility of the reinforced soil. The test medium used in this study is a river sand from Mei-Shi Nantou. A dry density γd of 15kN/m3 was used for all test of grounds. De-aired water was supplied from the base of the sand box to saturate the horizontal test grounds. In addition to the footing loads and settlements, pore water pressure and strains of reinforcement were measured at a frequency of 2 Hz in the loading tests on reinforced and unreinforced horizontal sandy grounds using a 100 mm-wide rigid strip footing. A major finding from this study is the significant influence of ground saturation to the behavior of bearing capacity. In particular, the influence of excess pore water on the delayed mobilization of reinforcement forced and ultimate footing pressures. A generic model for describing the mobilization of excess pore water pressure in reinforced horizontal ground is necessary for an accurate prediction of ultimate bearing capacity of saturated reinforced grounds.
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Matias, Vera Lucia Nora Fidalgo. "Perforation effect in the bearing capacity of shallow foundations." Master's thesis, 2016. http://hdl.handle.net/10316/38720.
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Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraCom a crescente crise na indústria de petróleo e gás, as empresas responsáveis pelo dimensionamento e instalação das estruturas de extração e exploração destes recursos, como a Subsea 7, têm que estar focadas cada vez mais na eficiência e qualidade dos seus serviços. A instalação das estruturas representa um papel importante nos projetos, não só porque constitui a fase crucial em que o produto é entregue mas também porque condiciona o dimensionamento da própria estrutura. À medida que a indústria cresce, surgem novos desafios obrigando a engenharia a desenvolver novas soluções. Atualmente, a exploração em águas profundas é cada vez mais comum, atingindo já profundidades superiores a 3500 metros. Por estas razões, aumenta o interesse das empresas petrolíferas em ter todos os equipamentos de exploração submersos, ao invés estruturas maioritariamente superficiais. No entanto, no fundo do oceano, os solos presentes são geralmente pouco competentes, tendo propriedades mecânicas bastante baixas, criando algumas dificuldades no dimensionamento das fundações das estruturas. Além disso, também nesta fase, devem ser tida em conta a capacidade dos navios de instalação das estruturas (por exemplo, a capacidade das gruas, espaço nas plataformas). Uma das soluções desenvolvidas para otimizar as fundações superficiais é a introdução de pequenos orifícios de forma a aliviar as forças aplicadas na estrutura e induzidas nas gruas na fase de instalação, sobretudo forças hidrodinâmicas. Contudo, esta solução tem também as suas desvantagens. A presente dissertação analisa o efeito da perfuração na capacidade de carga de fundações superficiais, denominadas mudmats, para estruturas offshore durante o seu ciclo de vida. Avalia e compara também diferentes configurações de perfuração, usando uma área perfurada de cerca de 30 a 40 % da mudmat, uma vez que é a percentagem mínima necessária para reduzir as forças hidrodinâmicas. De forma complementar, são analisados também estes efeitos aplicados a fundações reforçadas com saias. O estudo foi realizado usando modelos de elementos finitos tridimensionais, com recurso programa de cálculo da Rocscience, RS3. As principais conclusões a salientar são a pouca influência na capacidade de carga das fundações devido à forma dos furos, a maior capacidade de fundações que apresentam maior número de perfurações e, em alguns casos, a percentagem de perfuração pode atingir valores na ordem dos 40% sem afetar o desempenho da fundação.
With the Oil & Gas industry crisis, installation companies as Subsea 7 have to focus more than ever in efficiency and quality of their services. Installation of structures takes a big role in projects, not just because it is the critical phase where the company delivers the product but also because it can condition the design of the product itself. While the industry goes forward, new challenges are found and new engineering solutions need to be developed. Nowadays, deep water field exploration is becoming more common (up to 3500 m water depth). Hence, oil companies are rather keen on having all the field development subsea than having the structures at surface. Geotechnical Engineer plays a big role in the development and improvement of efficient foundation solutions needed in these field architectures. The geological properties of the seabed under deep water are commonly very poor (e.g. soft clays) which creates difficulties during the structures foundations design phase. In addition, during design phase geotechnical engineers are limited by the capabilities of the installation vessels (e.g. crane capacity, deck space).One of the proposed solutions for the optimization of shallow foundations is to insert small perforations to reduce de forces applied to the structure and transmitted to the crane during the installation process. However, this solution also has its disadvantages. The present dissertation analyses the effect of perforation on shallow foundations, known as mudmats, for offshore structures during design life. Assesses and compares different perforation configuration, using a ratio between 30 and 40% of the foundation footprint, since it is the minimum perforation ratio needed to reduce the hydrodynamic loads. Moreover, analysis for skirted foundations are also performed. The study was conducted using 3D finite element models, using Rocscience computer program RS3. The main conclusions were that the holes’ shape has small influence on the foundation bearing capacity; foundations with a greater number of holes tend to have higher bearing capacity; the perforation ratio for some cases can be increased up to about 40% without affecting the foundation capacity.
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Chung, Chi-Hsien, and 鍾繼賢. "Effects of Soil Density on Bearing Capacity of Spudcan." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/90454182432953489803.
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碩士國立交通大學
土木工程系所
104
In this study, the effects of soil density on the bearing capacity of the spudcan penetrating submerged sandy soil were investigated. Ottawa sand was used as soil specimen and 1g physical model tests were carried out. The testing facilities constructed at the National Chiao Tung University consisted of the vertical loading system, soil bin, spudcan, and data acquisition system. To simulate the seabed soils with different densities, the air pluviation method was used to prepare uniform soil specimens.Direct shear test results indicated that the peak internal friction angle of Ottawa sand increased with increasing soil density. An empirical relationship between and the peak friction angle and the relative density of soil was proposed. The residual internal friction angle of sand did not change with increasing soil density, and remained 31.7 degree. The dry sand in the soil bin was submerged, and then the air trapped in the submerged soil was removed by a suction of 0.5 atm for 9 hours. Submergence and suction significantly increased the density of the loose sand. However, little density change due to submergence and suction was observed in dense sand. The experimental bearing capacity of the spudcan penetrating soils with different densities were in fairly good agreement with those calculated with the equation suggested by SNAME (2008), using the peak internal friction angle of soil. This finding may be explained by the fact that, during the penetration of spudcan into the seabed, new failure surface were cut continuously in the undisturbed virgin soils, there fore it became necessary to use the peak shear strength of soil to determine the bearing capacity of the spudcan. The amount of ground heaving of the specimen increased with increasing soil density. The ground heaving is probably due to the contraction followed by dilation of dense sand under shearing. The position of maximum ground heaving was located between about 1.3~1.7 times diameter of spudcan from centerline.In the back-flow zone,the measured seabed inclination angle was almost identical to the residual friction angle 31.7 degree of the sand.This is because the soils on both sides of the penetratim zone back flowed to fill the cavaity due to spudcan penetrating . An angle of repose was formed on the surface of the back-flow zone.
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Menclova, Eva. "Estimating bearing capacity of piles installed with vibratory drivers." 1996. http://catalog.hathitrust.org/api/volumes/oclc/37312416.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1996.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 160-162).