Download or read book The Effect of Carbonaceous Fines on the Liquefaction Potential of Sands written by Maha Kassim Saleh and published by . This book was released on 2005 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquake events over the past forty years have demonstrated that the potential damage to man-made structures associated with soil liquefaction can be very sig nificant. Whereas the phenomenon of liquefaction of relatively clean sands due to earthquake shaking is well understood, the case remains relatively unclear wh en fine grained materials are present within the sand matrix. No clear consensus exists regarding the effect of increased fines content on the overall response of sand deposits. A resolution of what appears in some reported studies as confl icting observations is of concern for land reclamation projects and sea fills, p articularly for cases where the material source is variable and contains signifi cant levels of fines. The nature of the fines themselves may have a measurable e ffect on the matrix behavior. The work presented herein explores the effect of s ilt and clay-size carbonaceous fines on the liquefaction susceptibility of sand. The choice of fines was guided by the conditions associated with the Lebanon co astal reclamation projects, where limestone/marlstone quarry source materials ar e dominant. The scope of the testing program included a large number of laboratory cyclic tr iaxial tests on reconstituted soil samples of varying composition. The sand chos en as the matrix material was a "standard sand" (Ottawa Sand-ASTM C109 graded sa nd). The effect of varying several parameters was evaluated, namely: relative de nsity, fines content, fines type/plasticity. The Ishihara 5% double amplitude st rain criterion was adopted as a basis to determine the onset of "liquefaction" a nd the cyclic resistance ratio (CRR). The results obtained confirm the significa nt effect of fines on the cyclic resistance of sands. They also confirm the exis tence of a limit fines content and a plasticity index (PI) threshold and establi sh their effect on observed behavior.
Download or read book Effect of Fines Content on Liquefaction Potential of Sands written by Duygu Erten and published by . This book was released on 1994 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Silt Size and Content on Static Liquefaction Potential of Sand written by M. Murat Monkul and published by . This book was released on 2011 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Different specimen preparation methods such as moist tamping, dry funnel deposition, slurry deposition, dry air pluviation have been reported in the literature to investigate the undrained behavior of silty sands. Similarly, different means have been used to densify the soils prepared with such methods. However, the influence of the densification technique, utilized within a particular deposition method, on undrained behavior (e.g. change in initial peak deviator stress and instability angle) was not known. Therefore, a new densification technique is developed for the dry funnel deposition method, which avoids tamping, vibrating or mold tapping. This new method of densification is thought to create a much consistent soil fabric for different amounts of densification than other specimen densification techniques. The experimental results show that the change in undrained behavior with increasing density produced by densification is much less pronounced when compared to the other densification methods reported in the literature. Prior research efforts regarding the effect of non plastic silts on the liquefaction behavior of sands mainly focused on the influence of fines content, confining stress, and depositional techniques. However, there is no consensus in the literature regarding the influence of fines content on the undrained behavior of silty sands. Strain-controlled monotonic undrained triaxial compression tests were performed on a single base sand mixed with three different essentially nonplastic silts. First, silt size effects are investigated while other factors like fines content (20%), confining stress (30kPa) and deposition method (dry funnel deposition) were kept the same. The results show that silt size is indeed an important factor which influences the liquefaction potential of silty sands. Different comparison bases for undrained behavior such as the loosest possible density after deposition, intergranular void ratio, void ratio and relative density were also evaluated. It was observed that as the mean grain diameter ratio (D50/d50) of the sand grains (D50) to silt grains (d50) decreases, liquefaction potential for a silty sand increases. This tendency is attributed to more metastable contacts with increasing silt size. Finally, the influence of fines content on the static liquefaction potential of silty sand is investigated for different silt types. It was found that if the mean grain diameter ratio (D[subscript 50-sand]/d[subscript 50-silt]) is sufficiently small, the liquefaction potential of the sand increases steadily with increasing fines content for the studied range (0-20%). As mean grain diameter ratio (D[subscript 50-sand]/d[subscript 50-silt]) increases, the liquefaction potential of the sand first decreases then increases with fines content. For such cases, liquefaction potential of the silty sand might be less than the liquefaction potential of the clean sand. Differences in undrained behavior are explained based on the influence of mean grain diameter ratio (D[subscript 50-sand]/d[subscript 50-silt]) on the initial soil fabric.
Download or read book The Effects of Non plastic and Plastic Fines on the Liquefaction of Sandy Soils written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The presence of silt and clay particles has long been thought to affect the behavior of a sand under cyclic loading. Unfortunately, a review of studies published in the literature reveals that no clear conclusions can be drawn as to how altering fines content and plasticity actually affects the liquefaction resistance of a sand. In fact, the literature contains what appears to be contradictory evidence. There is a need to clarify the effects of fines content and plasticity on the liquefaction resistance of sandy soils, and to determine methods for accounting for these effects in engineering practice. In order to help answer these questions, a program of research in the form of a laboratory parametric study intended to clarify the effects which varying fines content and plasticity have upon the liquefaction resistance of sandy sands was undertaken. The results of the study performed are used to clarify the effects of non-plastic fines content and resolve the majority of the inconsistencies in the literature. The effects of plastic fines content and fines plasticity are shown to be different than has been previously reported. The validity of plasticity based liquefaction criteria is established, the mechanism responsible for their validity is explained, and a new simplified criteria proposed. The effects of fines content and plasticity on pore pressure generation are discussed, and several recommendations are made for implementing the findings of this study into engineering practice.
Download or read book Cyclic behaviour and liquefaction potential of silty sand Experimental and numerical investigations written by Abdulaziz Osman Abdelkadr and published by BoD – Books on Demand. This book was released on 2023-01-01 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study experimental and numerical investigations have been carried out with the emphasis on studying the behaviour and liquefaction state of typical silty sand sampled from the Mekelle area in Ethiopia under monotonic and cyclic undrained loadings. Experiments have been carried out to measure the pore pressure accumulation, deformation characteristics and related effective stress paths. A numerical model was then used to simulate the behaviour and liquefaction state associated with the changes in the stress-strain-pore pressure levels by means of the finite element method (FEM) using the FE code Tochnog (Tochnog Professional Company 2021).
Download or read book Percentage Silt Content in Sands and Its Effect on Liquefaction Potential written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Non Plastic Fines on Minimum and Maximum Void Ratios of Sand written by PV. Lade and published by . This book was released on 1998 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of sand is affected by the content of nonplastic fine particles. How and to what degree the fines content affects the minimum and maximum void ratios has been studied in detail. A review is presented of previous theoretical and experimental studies of minimum and maximum void ratios of single spherical grains, packings of spheres of several discrete sizes, as well as optimum grain-size ratios to produce maximum densities. A systematic experimental study is performed of the variation of minimum and maximum void ratios with contents of fines for sands with smoothly varying particle size curves and a large variety of size distributions. It is shown that the fines content plays an important role in determining the sand structure and the consequent minimum and maximum void ratios. It is indicated how the fines content and sand structure affects the compressibility and the static liquefaction potential of the sand.
Download or read book Study of the Influence of Fine Particles on the Properties of Liquefaction of Sands written by Layal Jradi and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the last 50 years, the study of the phenomenon of liquefaction of saturated sandy soils has been a topic of extensive laboratory research. Most of the earlier research has focused on the liquefaction of clean sands assuming that the presence of fines resists the development of pore water pressure as well as the risk of liquefaction. However, natural sand is found in nature under the form of a mixture of sand and fines and, the influence of these fines on the liquefaction risk of this type of material is still unclear. In fact, we could find contradictory results in the literature review of the effect of fine particles on the sand liquefaction phenomenon. In this context, the main objective of this study is to clarify and quantify the influence of fine particles (plastic and non-plastic) present in a sandy matrix on the initiation and development of the liquefaction phenomenon .We've focused, in particular, on the nature of fine particles (plastic/non-plastic), their proportion in the matrix, the matrix compactness condition and initial stress state (state consolidation). For this purpose, with the aid of a new triaxial servo-hydraulic device, a series of monotonic and cyclic tests were done in order to clarify this effect. Experimental results show that the increase in non-plastic fines increases the resistance to liquefaction of the mixture under both monotonic and cyclic loading. However, this trend is reversed for the mixtures containing plastic fines. Finally a comparison has been established between the behavior of these soils under undrained monotonic and cyclic shearing in terms of evaluation of the initiation of instability phenomenon and other mechanical parameters.
Download or read book Percentage Silt Content in Sands and Its Effect on Liquefaction Potential written by Lester Paul Kaufman and published by . This book was released on 1981 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics and Mechanics of Soil Liquefaction written by PoulV. Lade and published by Routledge. This book was released on 2018-04-27 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: The workshop aims to provide a fundamental understanding of the liquefaction process, necessary to the enhancement of liquefaction prediction. The contributions are divided into eight sections, which include: factors affecting liquefaction susceptibility and field studies of liquefaction.
Download or read book Liquefaction Potential and Post liquefaction Settlement of Saturated Clean Sands written by Maksat Omarov and published by . This book was released on 2010 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Liquefaction of saturated granular soils has been the cause of most geotechnical hazards during earthquakes. Development of excess pore pressures in saturated soils when subjected to cyclic loading has been shown to cause the liquefaction, which can be simply described as the transformation of stable soil structure into unstable liquid form. Majority of the previous laboratory studies have been focused on stress-controlled loading. However, the generation of excess pore pressure is better characterized by the induced shear strains. The objectives of this study were: (i) to investigate the liquefaction potential and post-loading volumetric strain of saturated clean sands through strain-controlled testing; and (ii) to study as an alternative mitigation technique, the influence of geofiber reinforcement on exess pore pressure generation and post-liquefaction settlement of saturated sands. Undrained, strain-controlled, cyclic triaxial tests were performed in the following categories: (1) tests performed under different effective consolidation stresses; (2) tests performed at various number of loading cycles; (3) tests performed at different relative densities; and (4) tests performed on geofiber-reinforced sand specimens. The liquefaction potential of specimens subjected to different levels of shear strains were investigated with respect to the developed excess pore pressures. Reduction in the volume of the specimens with the dissipation of generated excess pore water pressure was studied by allowing for drainage after cyclic loading. Additionally, the influence of geofibers as a possible mitigation measure against the excess pore pressure development and post-loading volumetric straining of clean sands was investigated. The results from this study were used to develop insight into the behavior of clean and geofiber-reinforced sands under seismic loading conditions. Based on the test results, geofiber-reinforced seismic loading conditions was found that the number of loading cycles has significant influence on the generation of excess pore pressure and post-loading volumetric strain. Specimens subjected to continued loading after initial liquefaction indicated about three times larger volumetric strains when compared to those allowed to drain after initial liquefaction. Soil specimens consolidated to 100kPa effective stress were found to experience less volumetric strain than that observed in specimens consolidated to 400kPa effective consolidation stress; however, the excess pore pressure generation at 100kPa effective stress was about two times larger than that measured at 400kPa effective stress. In general, geofiber-reinforced specimens showed less excess pore pressures when compared to clean sand specimens; while post-loading settlement were observed to be nearly two times larger for specimens with 1%geofiber content when compared to clean sand specimens"--Leaves iii-iv.
Download or read book Effects of Overconsolidation on Liquefaction Characteristics of Sands Containing Fines written by K. Ishihara and published by . This book was released on 1978 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two series of cyclic triaxial tests were performed on soils containing fines (passing \200 sieve) from 0 to 100 percent by weight. The first series included the testing of laboratory-prepared reconstituted specimens overconsolidated to overconsolidation ratio (OCR) values of 1.0 to 2.0. It was shown that the overconsolidation had an definite effect in strengthening the cyclic resistance of the specimens, and its effect became more pronounced as the content of the fines increased. The second in the series was concerned with the tests on undisturbed specimens from alluvial deposits in Tokyo as well as the tests on remolded specimens of the same soil. It was shown that the cyclic strength of the undisturbed specimens was about 15 percent greater than that of the reconstituted ones. Comparison of the results from this second series of tests appeared to show that the greater cyclic strength of the undisturbed specimens over that of the remolded specimens might have been caused by a slight overconsolidation which existed in the alluvial deposit of the sands containing the fines.
Download or read book Effect of Packing on Settlement Pore Pressures and Liquefaction of Sands written by Robert Kent Green and published by . This book was released on 1976 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Estimating Liquefaction Potential of Sands Using the Piezovane written by Clinton E. Scott and published by . This book was released on 1989 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Earthquake Geotechnics written by T. G. Sitharam and published by Springer Nature. This book was released on 2022-01-04 with total page 547 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents select papers presented at the 7th International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics. The papers discuss advances in the fields of soil dynamics and geotechnical earthquake engineering. Some of the themes include ground response analysis & local site effect, seismic slope stability & landslides, application of AI in geotechnical earthquake engineering, etc. A strong emphasis is placed on connecting academic research and field practice, with many examples, case studies, best practices, and discussions on performance based design. This volume will be of interest to researchers and practicing engineers alike.
Download or read book Statistical Modeling of Liquefaction Resistance of Sands Containing Fines written by Hsing-Cheng Liu and published by . This book was released on 1992 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Grain Characteristics on Liquefaction Potential In Search of Standard Sand for Cyclic Strength written by I. Ishibashi and published by . This book was released on 1985 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the original Monterey 0 sand, which had been used for cyclic triaxial testing system calibration, is not available any more, the search for an alternative sand was started. In order to provide useful information for the above purpose, liquefaction potentials were evaluated for Monterey 0 and 0/30 sands and for ASTM Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube) (C 109) Ottawa sands from various sources. The results clearly indicated that the liquefaction potential was very sensitive to slight changes in material properties (mean grain size, coefficient of uniformity, sphericity, and volume decrease potential).
