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Sung-Ryul Kim

Other affiliations: Konkuk University
Bio: Sung-Ryul Kim is an academic researcher from Seoul National University. The author has contributed to research in topic(s): Intrusion detection system & Cluster analysis. The author has an hindex of 10, co-authored 74 publication(s) receiving 335 citation(s). Previous affiliations of Sung-Ryul Kim include Konkuk University.
Papers
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Journal ArticleDOI
Abstract: A series of 1 g experimental tests was conducted to investigate the effects of embedment depth on the pullout capacity of bucket foundations in sand. Polycarbonate model buckets with a constant diameter of 150 mm and length-to-diameter (L/D) ratios of 0.5, 1.0 and 1.5 were employed varying loading rates from 0.002 N/s to 4.1 N/s. The slow loading rate of 0.002 N/s induced drained conditions characterised with substantially small suction force and high skirt resistance. The fast loading rate of 4.1 N/s induced nearly undrained conditions characterised by large suction force and almost full uplift of the soil plug. The pullout capacity increased almost linearly with the L/D ratio. A 50% increase in embedment depth resulted in an average increase in pullout capacity of 40%. The pullout capacity and suction force inside the bucket rapidly increased with the loading rate in the partially drained condition, and converged to nearly constant values in the undrained condition. In the nearly undrained condition, the suction force at the tip was approximately half of that under the lid. The simplified approach reasonably predicted the capacities of buckets with various L/D ratios.

Journal ArticleDOI
Abstract: Various liquefaction vulnerability indices (LVIs) have been proposed to quantify the severity of liquefaction, and used to create the liquefaction hazard map. In producing the liquefaction hazard map, the spatial variability of LVI is important because the number of available in-situ data is typically limited, and the values at the unmeasured locations are predicted using kriging operations that consider the spatial correlation of observed values. In addition, the liquefaction hazard map may vary significantly depending on how LVI was spatially interpolated. This study aims to evaluate the spatial variability of soil properties based on cone penetration test (CPT) data, and to investigate the changes in geostatistical properties of LVIs depending on shaking intensity. A simplified CPT-based procedure was used to calculate the factor of safety against liquefaction, and the geostatistical properties of LVI according to shaking intensity were evaluated using the parameters of semivariogram. In addition, the LVIs at unmeasured locations were predicted using two geostatistical modeling approaches, and their results were compared to investigate the accuracy of geostatistical approaches in predicting LVIs according to the peak ground acceleration (PGA).

1 citations


Journal ArticleDOI
Abstract: This study aims to evaluate the slope effect on the dynamic p–y backbone curve, which is a worldwide simplified tool in the seismic design of pile foundations. Data of dynamic centrifuge tests on single and group piles in sloping sandy ground were adopted to derive soil resistance and pile displacement. Meanwhile, the free-field soil displacement was computed by performing three-dimensional numerical simulations of centrifuge models excluding the pile-supported structure. Dynamic p–y loops of soil resistance and pile displacement relative to the free-field soil displacement showed an irregular shape with the occurrence of large residual displacement. The soil resistance mobilized at the free-head pile was smaller than that at the fixed-head pile because of the difference in the phase responses. An empirical factor was introduced to account for the slope effect on the dynamic p–y backbone curve, which was formed by fitting peak points of the dynamic p–y loops with a hyperbolic function. Pseudo-static analyses applying the suggested dynamic p–y backbone curve showed good agreement with the centrifuge test data.

Journal ArticleDOI
Abstract: This study aimed to numerically evaluate the strength parameter of the soil–pile interface in the lateral direction. A 3D numerical model of a single pile in sandy soil was built to analyse the interface strength parameter, which was defined as the ratio of the lateral force mobilised on the interface to the confining stress multiplied by the pile perimeter. Results showed that the interface strength parameter increased with the embedment depth ratio and converged to a constant value at a depth of four times the pile diameter. This relationship can be expressed using a bilinear formula that can be adopted to define the strength of springs connecting soil and pile elements in the lateral direction. The applicability of the proposed strength parameter to seismic analysis was validated by performing 3D numerical simulations of centrifuge tests. The simulation targeted single and group piles installed in a level ground of dry silica sand. The simulation results agreed well with the measured data, indicating the reasonable applicability of the proposed strength parameter of the soil–pile interface in the lateral direction.

2 citations


Proceedings ArticleDOI
Myeong-Kyu Kim1, Sung-Ryul Kim1Institutions (1)
13 Oct 2020
TL;DR: This work proposes a system that uses less computation than previous works with similar false positive rate and which is implemented by using a circular bit shift and computes faster than previous studies with similarfalse positive rate.
Abstract: The Bloom filter is a hash-based data structure that facilitates membership querying. Computation speed of Bloom filter is affected by hash functions that produce hash outputs. Basically, two operations: 'add' and 'query', consists of the Bloom filter. Previous researches have shown advanced computation speed of Bloom filter since the standard Bloom Filter is published. For example, Double Hash Bloom filter, Single Hash Bloom filter, etc.We propose a system that uses less computation than previous works with similar false positive and which is implemented by using a circular bit shift. This method was implemented with faster calculation speed, compared with previous works. Furthermore, experiments which were compared with previous researches and standard Bloom filter. Therefore, we demonstrate that the proposed system computes faster than previous studies with similar false positive rate.

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Journal ArticleDOI
Sener Ceryan1, Nurcihan Ceryan1Institutions (1)
Abstract: In the present study, an approach is suggested for the settlement area where there is liquefaction and surface fault rupture hazard at the same time, which allows the assessment of land damage in case an earthquake occurred. Edremit (Balikesir NW Turkey), mainly under the influence the Edremit Fault Zone in the southern branch of the North Anatolian Fault Zone, was chosen as the study area. According to paleo-seismological findings from the Narli trench, at least three similar earthquakes occurred on the same rupture of Edremit Fault Zone passing in the studied area. In addition, generally the groundwater level in the liquefiable alluvial soil varies between 0.5 and 6 m, and also the ratio of areas of liquefiable soil varies between 56 and 78% at different depths in the area. The buffer zone for the Edremit Fault Zone ruptures was defined based on the distance from the surface fault rupture in the study area, and it was seen that 15% of the study area is within the first-degree fault avoidance zone, while 43.5% is located within free zone. The safety factor against liquefaction for the soil layers was determined by using simple procedure based on SPT-N values, and then, the spatial distribution of the liquefaction potential index was obtained. It is found that 43% of the study area has high or very high liquefaction potential while the rate of the area where liquefaction is not expected is 27.8%. The liquefaction potential and the map showing the fault avoidance zones are important and successful in terms of individual hazard related to earthquake. However, the said maps do not allow to assess, simultaneously and completely, the realistic extent of the possible land damage in case an earthquake occurs. So, using the liquefaction potential index and the distance from the surface fault rupture, a new index, namely land damage index, was defined to create the microzonation of the seismic hazard for liquefaction and surface fault rupture-induced land damage. According to the zonation of land damage index, 29.7% of the study area is consists of Land Damage Zone I where settlement is not allowed. The main goal of the preparation of the said microzonation for the study area is to recognize the hazard from active faults, with respect to liquefaction and surface fault rupture, and to provide guidance to planners on how to mitigate the risk for different types of buildings.

Journal ArticleDOI
Abstract: A series of 1 g experimental tests was conducted to investigate the effects of embedment depth on the pullout capacity of bucket foundations in sand. Polycarbonate model buckets with a constant diameter of 150 mm and length-to-diameter (L/D) ratios of 0.5, 1.0 and 1.5 were employed varying loading rates from 0.002 N/s to 4.1 N/s. The slow loading rate of 0.002 N/s induced drained conditions characterised with substantially small suction force and high skirt resistance. The fast loading rate of 4.1 N/s induced nearly undrained conditions characterised by large suction force and almost full uplift of the soil plug. The pullout capacity increased almost linearly with the L/D ratio. A 50% increase in embedment depth resulted in an average increase in pullout capacity of 40%. The pullout capacity and suction force inside the bucket rapidly increased with the loading rate in the partially drained condition, and converged to nearly constant values in the undrained condition. In the nearly undrained condition, the suction force at the tip was approximately half of that under the lid. The simplified approach reasonably predicted the capacities of buckets with various L/D ratios.

Journal ArticleDOI
Ningxin Yang1, Mi Zhou1, Yinghui Tian2, Xihong Zhang3Institutions (3)
Abstract: Bucket foundations are widely constructed for offshore wind turbines, which are subjected to combined vertical-horizontal-moment (V-H-M) loading during operation. This technical note presents an extensive investigation into the response of bucket foundations in soft clay interbedded with a stiff clay layer (or soft-stiff-soft clays) under combined loading, which is a supplement to the existing design specification. The numerical method employed in this study is validated by comparing the bearing capacities of bucket foundations with previously published data. The numerical modeling results from this study show that the failure mechanism of bucket foundations in soft-stiff-soft clays under combined loading is significantly different from that in single-layer soft clay condition. A series of numerical analyses are conducted to explore the effects of geometric variation with the interbedded stiff clay, soil material properties and combined loading onto the bearing capacities of bucket foundations. Based on the parametric studies, a new failure mechanism for bucket foundations in soft-stiff-soft clays under general loading is obtained. And a corresponding design method is established, which can be used to calculate the monotonic vertical, horizontal, and moment bearing capacities, as well as the capacity envelopes under combined loading.

1 citations



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Performance
Metrics

Author's H-index: 10

No. of papers from the Author in previous years
YearPapers
20214
20206
20181
20157
20148
20138