State-of-the-art of geotechnical earthquake engineering practice

Finn, W. D. Liam

doi:10.1016/s0267-7261(00)00033-6

Cited by 51 publications

(18 citation statements)

References 22 publications

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“…A wide variety of field and laboratory techniques are available for this purpose each with having different advantages and limitations with respect to different problems. In the last century, a significant progress has been done in terms of identifying soil liquefaction and associated ground failures [1,2].…”

Section: Introductionmentioning

confidence: 99%

Effect of Irregular Time-History on the Cyclic Resistance of Sand

Türköz

Afacan

2019

Eskişehir Technical University Journal of Science and Technology a - Applied Sciences and Engineering

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The liquefaction behaviors of sandy soils are generally investigated using stress or strain controlled dynamic tests in the laboratory. In terms of ease and applicability of analysis, uniform loading patterns are usually preferred. However, irregular wave forms with different amplitudes and frequencies are generated throughout the soil layers during seismic excitations. In this study, a comprehensive series of cyclic tests have been performed on clean sand samples. Conventional uniform loading and ground-motion records scaled to different cyclic stress ratios were applied to identically prepared specimens. The pore pressure build-up and accumulated strain effects are investigated regarding the effect of the loading type and cyclic stress ratio. The outcome of test series aimed to provide further improvement on dynamic strength approaches for liquefaction assessment, in order to expand its use in current engineering practice. The results have shown that the frequency content plays an important role for the initiation of the liquefaction in terms of the number of cycles to liquefy soil.

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Section: Introductionmentioning

confidence: 99%

Effect of Irregular Time-History on the Cyclic Resistance of Sand

Türköz

Afacan

2019

Eskişehir Technical University Journal of Science and Technology a - Applied Sciences and Engineering

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“…The undrained liquefaction behaviour under static and cyclic loading was generally analyzed in terms of density indices such as the relative density, D r [22,23] and void ratio, e [24]. In this study, relative density was varied and corresponding void ratio was calculated.…”

Section: Introductionmentioning

confidence: 99%

“…Belkhatir et al [17,18] imply that the strength silty sand up to 50% fines content is less then that of the clean sand for constant dry density approach. Dash and Sitharam [19,20] proposed that the strength parameter initially increases till 5% silt content and thereafter decreases rapidly till around the limiting fines content (LFC) (explained in "Limiting fines content") and finally remain relatively constant for all the silt contents till even pure silt at constant relative density approach, though Karim and Alam [21] found this peak (for 5% silt content) when the specimens were prepared by air pluviation method not for moist temping method.The undrained liquefaction behaviour under static and cyclic loading was generally analyzed in terms of density indices such as the relative density, D r [22,23] and void ratio, e [24]. In this study, relative density was varied and corresponding void ratio was calculated.…”

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confidence: 99%

Effect of nonplastic silt content on undrained shear strength of sand–silt mixtures

Karim

Alam

2017

Geo-Engineering

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IntroductionNonplastic silt is a common alluvial deposit in the flood plain of Bangladesh. It is finer than sand and behaves like sand but different from elastic silt and clay. Sand and nonplastic silt are liquefiable whereas clay and elastic silt are not liquefiable. On the other hand, nonplastic silt content in sand-silt mixtures controls the behavior of the soil under monotonic and cyclic loading. Many researches are found in literature on the effect of nonplastic silt content in sand-silt mixtures. But, their findings are sometimes contradicts each other. Therefore, it is necessary to study the topic more. Moreover, design engineers are not aware of the behavior of nonplastic silt-sand mixtures.As a result of build-up of excess pore water pressure, the effective confining pressure decreases σ ′ = σ − u triggering liquefaction. Due to the lack of drainage within very short time during earthquake, this phenomenon mainly occurs and thus the undrained testing is commonly employed by the researchers to study the liquefaction behavior of soil. AbstractTo assess the behavior of sand-silt mixtures, strain-controlled monotonic triaxial tests were conducted on sand-silt mixtures of specimen size 71 mm in diameter and 142 mm in height at various relative densities but same isotropic effective confining pressure of 100 kPa. Concept of limiting fines content (LFC) was verified by these undrained monotonic triaxial tests. LFC was found to be the very important parameter to understand the behavior of sand-silt mixtures. The behavior of sand-silt mixture changes approximately at LFC. At constant relative density, increase in silt content decreases the undrained peak shear strength till LFC. After LFC the strength becomes near about same till pure silt sample. The reason of behavior could not be explained. At constant global void ratio, the peak shear strength decreases with increase in silt content till LFC and for further increment of silt content the peak shear strength increases. Sand-silt mixtures containing certain amount of silt which is near to the LFC showed flow type as well as brittle behavior. Failure of structure on this type of soil will be catastrophic during earthquake. In the case of permeability decreased with increasing silt content up to LFC. After the LFC, dry density is decreasing with increasing silt content but permeability remains constant till pure silt.Keywords: Liquefaction, Nonplastic silt, Peak shear strength, Limiting fines content, Relative density Open Access© The Author(s) 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Karim and Alam Geo-Engineering (2017) Karim and Alam Geo-Engineering (2017) 8:14 Liquefaction behavior by cyclic loading wa...

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“…Nowadays, the method with which site amplification is estimated is still a major concern and under investigation among seismologists and earthquake engineers. Developing methods for assessing the nature and potential of soil amplification is important, especially when choosing the location and design of critical and essential facilities [1], [2], [3]. Studying soil response means understanding earthquake source, source nature and distance, wave path, geologic context, upper soil properties, topography and primarily site effects [4], [5].…”

Section: Introductionmentioning

confidence: 99%