• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.679-686
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• 2020

In this study, the seismic vulnerability of public river levees was analyzed quantitatively. Input seismic waves were generated in Pohang seismic waves in return periods of 200, 500, 1000, and 2400 years. The behavior of the levee was analyzed by seismic vulnerability analysis according to the return period. The displacement that occurs during an earthquake showed the same tendency as the input seismic wave and was largest in the return period of 2400 years. An analysis of the sliding stability revealed a 31.5% and 26.7% decrease in the sliding safety factor for the return period of 2400 for the landside and waterside, respectively. An examination of liquefaction by the q/p' ratio showed that the seepage line inside the embankment rises due to earthquakes. As a result, in the case of a return period of 2400 years, most embankments generate liquefaction, making them vulnerable to earthquakes. Through this research, it will be necessary to re-establish domestic seismic-design standards and establish clear standards for the results through a dynamics method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.97-107
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• 2013

Culverts are structures constructed across river levees. Since river levees are to be constructed continuously, constructions of culvert are known to reduce the stability of river levees. In order to establish an effective inspection system of culverts, a visual inspection system using checklists and smart phone was recommended in this paper. It was determined that the recommended visual inspection checklist is applicable in establishing the investment priority based on the culvert's repair plan establishment, repair and precision safety inspection.

• Journal of the Korean Geotechnical Society
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• v.23 no.2
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• pp.35-45
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• 2007

In this research, artificially cemented sand which is made of a few portland cement and Nak-Dong river sand was researched closely. For providing the fundamental data which is needed in design and analysis of levee material, the shear behavior of cemented sands was investigated by drained triaxial test, and analyzed in accordance with the increase of cement content. The peak strength and elasitc modulus increased and dilation of cemented sand was restricted by the cementation, but after breakage of the cementation, dilation increased, cohesion intercetpt and friction angle increased with the increase of cement content and strain softening behavior appeared in stress-strain curve.

• Journal of Korea Water Resources Association
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• v.54 no.3
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• pp.181-190
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• 2021

In this study, a large-scale levee breach experiment from lateral overflow was conducted to verify the effect of the new reinforcement method applied to the levee's surface. The new method could prevent levee failure and minimize damage caused by overflow in rivers. The levee was designed at the height of 2.5 m, a length of 12 m, and a slope of 1:2. A new material mixed with biopolymer powder, water, weathered granite, and loess in an appropriate ratio was sprayed on the levee body's surface at a thickness of about 5 cm, and vegetation recruitment was also monitored. At the Andong River Experiment Center, a flow (4 ㎥/s) was introduced from the upstream of the A3 channel to induce the lateral overflow. The change of lateral overflow was measured using an acoustic doppler current profiler in the upstream and downstream. Additionally, cameras and drones were used to analyze the process of the levee breach. Also, a new method using 3D point cloud for calculating the surface loss rate of the levee over time was suggested to evaluate the performance of the levee reinforcement method. It was compared to existing method based on image analysis and the result was reasonable. The proposed 3D point cloud methodology could be a solution for evaluating the performance of levee reinforcement methods.

• Water for future
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• v.28 no.5
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• pp.163-174
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• 1995

A diffusion hydrodynamic model named "DFLOW-2" for the floodwave analysis from levee-break in protected lowland has been developed. The model has been applied to Ilsan levee-break, which occurred on September 12-13, 1990 in the downstream of the Han River. An unsteady flow analysis has been made in the reach from Indokyo to Junryu. Overflow through broken levee has been treated as internal boundary condition in the channel. A post-processor has been also developed to demonstrate the simulation results. The velocity distributions and inundated depths have been presented. The computed results have good agreements with observed data in terms of inundation depth, flood arrival time and flooded areas.ded areas.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.1-9
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• 2015

According to national regulations and its commentary, such as Rivers Design Criteria & Commentary (KWRA, 2009), Foundation Structure Guideline and its Commentary(MLTM, 2014 and KGS, 2009), the integrity evaluation of river levee includes slope stability evaluation of both riverside/protected low-land and piping stability evaluation with respect to foundation and levee body along with water level conditions. In this case the design hydro-graph can be the most important input factor for the integrity evaluation, however it is fact that the national regulations do not provide any proper determination methods regarding hydro-graph. The authors thus executed an integrity evaluation of sluice gate in levee by changing each hydro-graph factor, including rising ordinary water level, lasting flood water level, falling water level, and flood frequency, in order to suggest a determination method of reasonable hydro-graph. As a result, the authors suggested that at least over 57 hours of rising ordinary water level and over 53 hours of lasting flood water level should be considered for the design hydro-graph of sluice gate in levee at Mun-san-jae.

• Spatial Information Research
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• v.18 no.2
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• pp.25-34
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• 2010

This study simulated flood inundation each frequency rainfall using GIS spatial information and FLUMEN model for part of Muju-Namdae Stream. To create geomorphology for the analysis of flood inundation, Triangle Irregular Network(TIN) was constructed using GIS spatial interpolation method based on digital topographic map and river profile data, unique data source to represent real topography of the river areas. And also flood inundation was operated according to the levee collapse to consider extremely flood damage scenarios. As the analysis of result, the inundation area in the left levee collapse showed more high as 3.13, 3.69, and 4.17 times comparing with one of right levee for 50, 100, and 200 year frequency rainfall and showed 1.00, 2.15, and 3.34 times comparing with one of right levee in the inundation depth with over 1.0 meter, which can cause casualties. As the analysis of inundation area of the inundation depth with over 1.0 meter, which can cause casualties in left levee collapse, it increased more high as 263% and 473% when 50 year frequency change into 100 and 200 year frequency. Also As the analysis of inundation area of the inundation depth with over 1.0 meter in right levee collapse, it increased high as 123% and 142% when 50 year frequency change into 100 and 200 year frequency. Especially, the inundation area of the inundation depth with 3.0~3.5m showed more high as 263% and 489% when 50 year frequency change into 100 and 200 year frequency. It is expected that flood inundation map of this paper could be important decision making data to establish land use planning and water treatment measures.

• The Korean Journal of Quaternary Research
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• v.16 no.1
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• pp.17-27
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• 2002

Analysis of No. 199∼145 cross-sections set up by the Ministry of Construction (1978) in the middle reaches of the Sumjin River around Sunchang, Daegang, and Goksung areas have been done for delineating the changes In fluvial geomorphic features. The entire river-bed in the study area has been considerably degraded since 1978. In some cross-sections, the thalweg shillings are observed. Two aspects are responsible for the erosion-dominant environment. First, flow velocity has been increased. Human activities including wetland destruction, ex-channel destruction and artificial levee construction reduced the channel width, and fixed the channel geometry. This has resulted in increase of the water velocity. Pebble and granule∼coarse sand are prevailing on the river-bed, indicate the high speed of the currents. Second, aggregate has been intensively mined during 1980s∼1990s around the areas. Especially, in the right side of the cross-sections No. 188∼187 and the left side of the cross-section No. 155, erosion toward under the artificial levee is remarkable. This can be led to bank failure in case of heavy rainfall.

• Journal of Korea Water Resources Association
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• v.31 no.4
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• pp.415-427
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• 1998

FIAS (Flood Inundation Analysis System) using Arc/Info is developed and applied to the South Han River basin. The DWOPER model is revised and expanded to handle simultaneous multiple overtopping and/or breaking and to estimate the inundation depth and extents. The model is applied to an actual levee overtopping case, which occurred on August 23~27, 1995 in the South Han River. Stage hydrographs inside and outside of the levee are compared, then inundated discharges from overbank spilling are computed. The Graphic User Interface is developed with AML(Arc/Info Macro Language). Two-and three-dimensional inundation maps by Arc/Info are presented. The computed inundation extends agree with observations in terms of inundation depth and flooded area. Keywords : River, Floodwave, Flood Inundation, Geographic Information System.

• Journal of the Korean Geotechnical Society
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• v.34 no.3
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• pp.29-41
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• 2018

In the case of the enlargement levee on the soft foundation, the existing levee and the enlargement levee connection can be damaged due to heterogeneous subsidence such as differential settlement at the joint of the box culvert passing through the levee. This study selected the downstream region of the Geum River and then confirmed the influence of the piping possibility on the levee by performing a 2D seepage analysis and analyzing the seepage tendency according to the position of the box culvert's gate. As a result, the flow velocity and the hydraulic gradient are larger in the upper breakage than the lower breakage, and the upper leak was more vulnerable to the piping than the lower leak. If leaks occur in the gate located on the riverside land, the risk of piping is increased when the water level rises and is maintained highly. In the case of the gate located on the inland, it could be predicted that the leakage could damage the stability of levee by increasing the water pressure inside the levee. As a result, if leakage occurs at any position in the box culvert, the pore water pressure is increased or decreased compared with the case when no leakage occurs. Therefore, if the pore water pressure is drastically reduced or increased compared with the normal case, leakage may occur. However, the result of this study is based on a 2D seepage analysis, and it is likely to be different from actual cases. Therefore, more detailed analysis by 3D analysis is recommended.