• Geomechanics and Engineering
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• v.31 no.6
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• pp.637-651
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• 2022

The seismic design of embankment dams requires more comprehensive studies to understand the behaviour of dams. Deformations primarily control this behaviour occur during or after earthquake loading. Dam failures and incidents show that the impacts of deformations should be reviewed for existing and new embankment dams. Overtopping erosion failure can occur if crest deformations exceed the freeboard at the time of the deformations. Therefore, crest settlement is one of the most critical deformations. This study developed empirical formulas using Gene Expression Programming (GEP) based on 88 cases. In the analyses, dam height (H_d), alluvium thickness (H_a), the magnitude-acceleration-factor (MAF) values developed based on earthquake magnitude (Mw) and peak ground acceleration (PGA) within this study have been chosen as variables. Results show that GEP models developed in the paper are remarkably robust and accessible tools to predict earthquake-induced crest settlement of embankment dams and perform superior to the existing formulation. Also, dam engineering professionals can use them practically because the variables of prediction equations are easily accessible after the earthquake.

• Journal of the Korean GEO-environmental Society
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• v.8 no.2
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• pp.29-39
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• 2007

In this study, the centrifugal tests were fulfilled to analyze the displacement characteristics caused by the embankment construction on soft ground. Embankment of height, undrained shear strength and with or without geotextile were selected to evaluate the displacement characteristics of soft ground by embankment. As a result, the replacement section without geotextile showed the parabola shape. The replacement section with geotextile showed the trapezoidal shape which represents the uniform settlements. The replacement angle is increasing nearly lineally with increasing the height of embankment and G-level. The position, where the maximum horizontal displacement occurred, was between $0.24H_0$ and $0.35H_0$ and was at $0.3H_0$ on the average. In the case of with and without geotextile, the relationship between the maximum settlement of ground(S) and maximum horizontal displacement(${\delta}_m$) was ${\delta}_m$ = 0.60S, ${\delta}_m$ = 0.54S, respectively.

• Korean Journal of Agricultural Science
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• v.25 no.2
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• pp.260-270
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• 1998

The field tests were performed to suggest the rational method for stability evaluation of soft clay. The behavior of settlement-displacement obtained by field monitoring system was to compare and analyze the results of the observationed method, and to investigate the complex behavior of soft clay with filling height. The results of this study are summarized as follows. 1. The horizontal displacement was suddenly increased when physical properties of soft clay showed maximum values and the part of the turning point. The values of these properties were available to the fundamental data for stability evaluation. The shear deformation appeared that difference of the horizontal displacement was maximum values. 2. Although the stability of embankment by step filling showed the unstable part over the failure standard line, the embankment was confirmed stable. So the evaluation of the stability of embankment is reasonable to use the inclination of curve than failure standard line. 3. The horizontal displacement and relative settlement were increased as same ratio at improvement ground. Estimation of shear deformation using Terzaghi's modified bearing capacity should consider the relations of embankment load and undrained shear strength at nonimprovement ground, and minimum safety factor is recommended to use larger than 1.2. 4. Excess pore water pressure was increased with increasing of filling height and decreased with maintain the filling height. The embankment was unstable when filling height was exceed the evaluation standard line, and the behavior of excess pore water pressure and horizontal displacement could use as a standard of judgement of the filling velocity control because their behavior were agree with each other.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.71-82
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• 2018

This study presents a reasonable and economical DCM reinforcement length for the various factors (the embankment height, the distance from the embankment to the underground structure, the depth of the soft ground, and the compression index and the swelling index of the soft ground) that affect the stability of the structure due to lateral movement. Based on these results, we analyzed each factor's degree of influence and figured out which factor influenced the lateral movement most. The cross section of the embankment on the soft ground was modeled by using the Finite Element Program and reinforced with DCM. The results show that the increase rate of the reinforcement length with the increase of the embankment height is about 9~50%, the increase rate of the reinforcement length with the depth of soft ground is about 13~30%, and the increase rate of the reinforcement length with increasing compression index is about 3~25%. In addition, the influence of each factor on each other was analyzed. As a result, among the separation distance, the compressive index and the maximum to minimum slope ratio of the reinforcement length of the embankment height, the separation distance was the largest for the depth of soft ground. As the depth of the soft ground increases, the ratio of the maximum to minimum slope of the reinforcement length according to the embankment height is 3.75, the ratio of the maximum to minimum slope of the reinforcement length according to the spacing distance is 4.3, and the ratio of maximum to minimum slope according to compression index is 2.5. From these results, it is confirmed that the three factors are greatly affected by the depth of soft ground.

• KCID journal
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• v.18 no.1
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• pp.25-32
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• 2011

In order to effectively manage the reservoir, reservoir water quality management should be based on physicochemical and configurational characteristics. In this research, correlation between factors affecting the reservoir water quality was examined. Chl-a and COD shows the highest positive correlation. Chl-a and T-P also has a high positive correlation, however Chl-a and T-N show lower correlation relatively. Even though T-N is an important factor for phytoplankton growth which increase Chl-a concentration, corelation of Ch1-a and T-N shows that enough nitrogen in the reservoir isn't no longer limiting factor. The age of reservoir can cause of increasing COD and SS. Embankment height and elevation of reservoirs shows strong negative correlation to water quality. That means reservoir which is higher embankment height and locate in higher elevations is less contaminated. Regression expression was derived with Chl-a and water quality parameters, and height of reservoir. Finally Chl-a was simulated using regression expression and it was a good approach to predict the Chl-a concentration.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.282-291
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• 1985

In order to investigate the settlement characteristics of fill dam with decomposed granite is used as a embankment material instead of conventional clay collected behavoir of Andong dam and analyzed. Andong dam is the use of decomposed granite in the embankment material, and various type of gauges were installed in dam to measure a pore pressure, interval vertical settlement, dam crest settlement, relative settlement, surface settlement and internal horizontal movement. The results were summerized as follows; 1. With the increase of embankment loading, the settlement of core zone during construction increased with linear and under the effective stress $7kg/cm^2$ vertical settlement ratio ranged between 0.1 and 0.8% approximately and showed smaller value than that of fill dam with clay were used as a embankment material. 2. Though embankment loading was increased with about over central part of embankment height, the settlement of core zone in the lower part of the embankment was influenced slightly. 3. Pore pressure responsed sensitively with the increase of coefficient of permeability in core zone and settlement increased with pore pressure were dispersed. 4. During construction relative settlement in the lower part of the embankment has the largest influence on magnitude of the relative density and after construction settlement showed larger value in the core zone which has the largest compression height. 5. Settlement distribution of dam crest showed larger value in the central part, maximum section of dam, but smaller value in near the abutment.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.3
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• pp.57-69
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• 2011

This study examined the relationship between Phragmites australis' growth and sediment properties at mud tidal flat of Donggum-ri, Gilsang-myeon, Gangwha-gun, Incheon city. Field survey was carried out from May, 2010 to October, 2010. Water content, soil texture, electric conductivity and water table depth for sediment, density, height, dry weight and flowering for P. australis were examined at several plots from the starting point (the coastal embankment) to the end point of the two populations. The result was as follows. Firstly, the water table increased along distance from the embankment at one line (N-line) but was similar at the other line (S-line) in a P. asustralis population. Water tables were higher out of than within a P. australis population at two populations. Secondary, in N-line, the height and dry weight of P. australis decreased along the distance from embankment but, in S-line, those were similar in its population. P. australis' growth was dependent on electric conductivity at lower layer (water table level) rather than upper one (the surface). Thirdly, density of P. australis changed during growing season and was similar in a population, except for the end point of patch. In summary, the growth and distribution of P. australis were dependent on salt content of tidal flat's sediment (water table level) and this was affected by fresh water of the inland.

• Wind and Structures
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• v.1 no.4
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• pp.303-315
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• 1998

Full-scale measurements have been made to determine the increase in wind speed over two exposed embankments, one of $23^{\circ}$ slope and 4.7 m in height, the other of $24^{\circ}$ slope and 7.3 m in height. Measurements were made at heights of 5, 10 and 15 m above the upper edge of each embankment and at the same heights approximately 100 m upwind in the lower-level approach fetch. Despite the modest sizes of the embankments, the maximum recorded increase in mean wind speed was 28% and the minimum was 13%; these increase relate to increases in wind loads on structures erected at the top of the embankments of 64% and 28% respectively. The associated increases in gust speeds are estimated at 33% and 18%, which imply increases in gust loading of 77% and 39% respectively. These experimental results are compared with predictions obtained from a computational fluid dynamics (CFD) analysis, using three high Reynolds number eddy-viscosity models and estimates from the UK wind loading code, BS 6399: Part 2. The CFD results are generally in agreement with the experimental data, although near-ground effects on the embankment crest are poorly reproduced.

• Proceedings of the Korean Geotechical Society Conference
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• 1995.06b
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• pp.15-34
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• 1995

The deformations of ground due to the embankment on the soft clay affect the stability of embankment. This study compares the result of Korea's measured values with foreign's results. And it examines the irregularity of the soil behavior depending on the characteristics of the ground, and the results can be used as the base data for studying the complex factors on the soft ground. Meanwhile, several problems of applying the conventional methods to the domestic field are also discussed. The purpose of the study is to aid the regulations concerning the safety of the embankment on the soft clay, Especially, consideration of depth of the soft ground, embankment height and stress history, etc. should be added to existing factors of correlation between the lateral displacement and the vertical displacement.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.83-91
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• 2002

Stability analysis of rocky embankment slopes is done by both the limit equilibrium method and the finite difference method. The height or the rocky embankment is approximately 40 m and the side slope is 1 vertical to 1.5 horizontal. The cohesion and internal friction angle of rock debris are assumed zero and 43$^{\circ}$, respectively. For finite difference analysis, strength reduction method is used to calculate the saft factor of the slope. As a result, the safety factor of the slope is discovered to be 1.4 by using either methods. Considering that the design criteria of the safety factor is 1.3, it can be judged that the rock fragments embankment slope is in a stable state.