• Economic and Environmental Geology
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• v.32 no.2
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• pp.169-175
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• 1999

The water leakage of reservoir embankment usually occurs through water vein, which gives little influence on the embankment in a normal state. However, the embankment can be destroyed when the water level of reservoir increases with heavy rain in summer. Investigating the water vein and its path is therefore very important from the viewpoint of disater prevention and embankment protection. This paper presents survey results of one-meter-depth ground temperature and multi-point temperature logging in an embankment in Japan to delineate water veins and permeable formations. Four water veins have been predicted in the embankment by comparing measured one-meter-depth ground temperatures with the background ones which have no effect of water vein. The multi-point temperature logging was carried out in the borehole drilled at one of the predicted water veins. Depth and thickness of the permeable formation in the borehole can be determined from temperature restoration ratios with elapsed time. From these results we can find that the water leakage of reservoir embankment mainly occurs in sandy soil formation in the embankment.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.2
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• pp.59-66
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• 2010

This study was performed to develop the embankment protection method that can reduce demage by prevention of embankment loss and collapse from overflow due to heavy rain and flood. For overflow test, model dam was prepared and embankment behaviors were monitored with the established piezometer and strain meter during overflow. As a result of overflow test for model dam, in case of embankment without waterproof mat, the lower end of embankment was collapsed within 40 seconds after beginning of overflow. On the other hand, in case of embankment with waterproof mat, embankment collapse didn't occurred during overflow. Accordingly, establishment of waterproof mat for embankment showed that be absolutely effective for the embankment protection during overflow in reservoir. Also, it showed that the minimum establishment range of waterproof mat to prevent embankment collapse in reservoir is from maximum storage level to the lower end of embankment.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.73-84
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• 2015

An embankment raising project on 113 agricultural reservoirs in Korea was implemented in 2009 to increase water supply capacity for agricultural water and instream uses. This study evaluated the future water supply capacity of the Imgo reservoir at which the agricultural reservoir embankment raising project was completed, considering climate change scenarios. The height of the embankment of the reservoir was increased by 4.5 m, thereby increasing its total storage from 1,657.0 thousand to 3,179.5 thousand cubic meters. To simulate the reservoir water storage with respect to climate changes, two climate change scenarios, namely, RCP 4.5 and RCP 8.5 (in which greenhouse gas reduction policy was executed and not executed, respectively) were applied with bias correction for reflecting the climate characteristics of the target basin. The analysis result of the agricultural water supply capacity in the future, after the agricultural reservoir embankment raising project is implemented, revealed that the water supply reliability and the agricultural water supply increased, regardless of the climate change scenarios. By simulating the reservoir water storage considering the instream flow post completion of the embankment raising project, it was found that water shortage in the reservoir in the future is not likely to occur when it is supplied with an appropriate instream flow. The range of instream flow tends to decrease over time under RCP 8.5, in which the greenhouse gas reduction policy was not executed, and the restoration of reservoir storage was lower in this scenario than in RCP 4.5, in which greenhouse gas reduction policy was executed.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.11-17
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• 2012

In this study, an experiment with large-scale model was performed according to raising embankment in order to investigate the cause of collapse by a change in water level of reservoir. Also, the settlement and pore water pressure by high water level and a rapid drawdown were compared and analyzed. After raising embankment for inclined core, there was no infiltration by leakage. For the vertical core, the pore water pressure showed a largely change by faster infiltration of pore water than in the inclined core. In a rapid drawdown, inclined core was remained stable but vertical core showed a largely change in pore water pressure. A settlement after a raising embankment showed a larger measure of settlement than before the raising embankment. The leakage quantity before a raising embankment and an inclined extension showed no leakage. Leakage in vertical extension was measured 160 $l$. From the result, a instrument system that can accurately estimate a change of pore water pressure shall be established for a rational maintenance and stabilization of raising embankment for agricultural reservoir.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.2
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• pp.27-33
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• 2011

This study is a preliminary investigation into the development of a construction method that will protect a reservoir even during over flows caused by severe flooding. Through hydraulic modeling tests, the destructive phenomena caused by spillway-junction scour during reservoir overflow were modeled, and the effects on the embankment during such an overflow and the spillway-junction movements are discussed. The reservoir destruction model used the Tanbu reservoir, located in Gangwondo Chuncheon-si Namsanmyeon (H＝22 m, L＝115 m), as the model reservoir and created an embankment with a 1/60 ratio. We review the spillway-junction safety factor during overflow and embankment movement following reinforcement measures for three different cases: no reinforcement, cemented sand and gravel (CSG) reinforcement and water-blocking sheet reinforcement. The results of this study confirmed that when the spillway-junction is exposed to soil, it is very vulnerable to overflow and that a water-blocking sheet or CSG reinforcement are very effective measures in preventing embankment destruction in the long-term period.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.6
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• pp.33-43
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• 2009

This study analyzed data on the pore water pressure, the ground water level, the horizontal displacement and the resistivity monitoring from instrument system, which is established to evaluate the safety in reservoirs. The pore water pressure in the embankment ranged from $0.035{\sim}1.116kg/cm^2$. The seepage that piping showed, as well as the leakage from the reservoirs are acceptable for the safety management of the reservoir. The maximum horizontal displacement and direction analyzed from the measured inclinometer data gives us very effective information to evaluate the safety in reservoirs. The resistivity monitoring technique, which is obtained on the reservoir crest, is an efficient tool to detect leakage zone. The safety index (SI) was predicted by the resistivity monitoring, and was evaluated to have a safety level of 0.8-1.0 at all reservoirs. Safety evaluations of reservoir through instrument systems are effective when studying the embankment, when the results of the instrument system have been analyzed compositively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.787-799
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• 2017

Although the long-term leakage between the box culvert and the soil contact surface is one of the main causes of the failure in the embankment of the reservoir, there is a little studies on this matter. If a leakage occurs by the structure such as the buried box culvert of reservoir embankment is partially damaged, it is difficult to observe and there is a possibility of damage caused by piping. For these reasons, more research is necessary. In this study, the embankment type of the reservoir is divided into the core type and the homogeneous type when the damaged box culvert passing through the embankment of the reservoir is leaked due to the differential behavior of materials like differential settlement. In view of the condition, the seepage analysis of 2D was performed according to the water level change. The result of the study shows that the possibility of piping increases at the upper part rather than the bottom part of the box culvert when the leakage occurs to the box culvert passing through the embankment of the reservoir. Particularly, it is considered that the presence of the core helps to maintain the seepage stability of the embankment in case where the leakage occurs at the downstream side of the embankment. Also, if there is a drastic decrease on the internal pore water pressure in the embankment of reservoir, it is necessary to consider the possibility of piping.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.1
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• pp.49-56
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• 1998

Ths study was peformed to evaluate the degree of degradation and safety of a small agricultural reservoir, Kosam Reservoir, in Kyungki Province. Evaluation was done by the program developed by the authors. Results of the study are as follows: 1) Although many burrows were found in downstream side of embankment and cracks were found in wall joining spillway, it appeared that degree of degradation of embankment was in good conditions. 2) Compressive strengths of concrete of crest, side channel, chute floor of spillway were in poor condition. But it appeared that overall degree of degradation of structures was in medium condition based on the criteria of the evaluation system 3) From the analysis of slope stability, safety factor of downstream slope was over 3.3 for the worst condition, such as flood and high water level and that of upstream slope was also over 3.6 for rapid drawdown. In case of earthquake, safety factors were over 2.5 for all conditions. Therefore embankment slopes of Kosam Reservoir were very stable for normal and earthquake condition. 4) As upon assumed failure of embankment of Kosam Reservoir, degree of damage was estimated to be very serious because of many loss of life and properties in the downstream area. 5) Overall grade of safety of Kosam Reservoir was in good condition. Therefore safety was considered to be "No problems" at the present time but further degradation may be proceeded partly and continuously as time goes by.e goes by.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.840-851
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• 2010

This study analyzed data on the pore water pressure, the ground water level, the horizontal displacement and the resistivity monitoring from instrument system, which is established to evaluate the safety in reservoirs. The pore water pressure in the embankment ranged from $0.035{\sim}1.116kg/cm^2$. The seepage that piping showed, as well as the leakage from the reservoirs are acceptable for the safety management of the reservoir. The maximum horizontal displacement and direction analyzed from the measured inclinometer data gives us very effective information to evaluate the safety in reservoirs. The resistivity monitoring technique, which is obtained on the reservoir crest, is an efficient tool to detect leakage zone. The safety index(SI) was predicted by the resistivity monitoring, and was evaluated to have a safety level of 0.8-1.0 at all reservoirs. Safety evaluations of reservoir through instrument systems are effective when studying the embankment, when the results of the instrument system have been analyzed compositively.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.107-112
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• 2007

To establish the reinforce region and technique through the embankment dike after identifying the region of seawater inflow, we carried out small-loop electromagnetic (EM) survey, electrical resistivity survey and refraction seismic method. We also analyzed the distribution of electrical conductivity in reservoir with depth every two month and monitored water level variations with tidal variation in four observation wells located at seaside and reservoir side in order to analyze the relationship with survey results. From both the cross-correlation between tidal and water level variation at four wells and the distribution of electrical conductivity in reservoir with depth, the major portion of seawater inflow are identified through the embankment dike. From electromagnetic and electrical resistivity survey results, it was found that the seawater inflow were happened through several small regions at seaside and became wider near reservoir side. The 2-D inversion sections of refraction seismic method showed that the pebble-bearing sand layer is spread over the whole region with two to four width. From the this study, small-loop EM, electrical resistivity and refraction seismic surveys accompany with the distribution of electrical conductivity in reservoir with depth and the monitoring results for water level variations are revealed to be effective to identify seawater inflow pathway through embankment dike and to establish the reinforce region and technique through the embankment dike.