• Journal of the Korean Professional Engineers Association
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• v.43 no.6
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• pp.31-34
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• 2010

Recently, due to localized heavy rain and flash floods in urban areas is becoming more frequent flood damage. To prevent flood inundation damage, to formulate the diverse directions in connection with the drainage system of buildings, roads, sewerage, pump stations, detention (retention) pond, and streams is very important. In addition, it is important for the uniform design criteria, the consistent of hydrologic and hydraulic analysis method, and a flood disaster mitigation systems connected with structural and nonstructural measures. To accomplish this, the method such as installation of storage facilities, infiltration facilities, and underground water tank, the optimal size of the design gutter and grate of the road, ensure the capacity of pumping stations, and the installation of a flood control channel into the deep underground requires comprehensive measures dimension in urban areas.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.25-36
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• 2008

When constructing subsea underground structures, the influence of high water and seepage pressure acting on the structures can not be neglected. Thus hydro-mechanical coupled analysis should be performed to estimate the behavior of the structures precisely In practice, relaxed rock load is generally used for the design of tunnel concrete lining. A method based on the distribution of local safety factor around a tunnel was proposed for the estimation of a height of relaxed rock mass ($H_{relaxed}$). In this study, the validation of the suggested method is investigated in the framework of hydro-mechanical coupled analyses. It was suggested that inducing inflow by pumping through a drainage well gave more reliable results than inducing inflow with shotcrete hydraulic characteristics in case of rock condition of Class III. In this study, therefore, inducing inflow by pumping through a drainage well are adopted in estimating $H_{relaxed}$ due to a tunnel excavation with the rock condition of Class I, III, and V. Also the estimated $H_{relaxed}$ results are compared with those of the existing suggested methods. As the result of this study, it is confirmed that estimating $H_{relaxed}$ based on the distribution of local safety factor around a tunnel can be effectively used even for the case of hydro-mechanical coupled analysis. It is also found that inducing inflow pumping through a drainage well gives more precise and consistent Hrelaxed of a subsea structure.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.2
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• pp.31-39
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• 1997

Between 40,000 and 60,000 liters of light oil were spilled when an underground pipe broke at a newly constructed landfill site in coastal area, Korea. Methods were presented to examine the subsurface distribution of the contaminants in hydrocarbon-contaminated soil. As results, large quantities of oil and grease were found to have migrated horizontally at the site. Oil and grease plume at concentrations of 38-88 mg/kg was formed horizontally through silty sand with gravel fill and the vertical movement of the contaminants was thought to be limited to groundwater level between 2 and 4 m corresponding to sea water level. Right after finding the leakage area, the early action of excavation and pumping out the mixture of groundwater and oil was taken and it was proved to be very effective for preventing further contamination. Two months after the leakage, oil and grease in sea water sample near contaminated area was not detectable.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.149-162
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• 2010

The most serious problem in oil stockpiles with artificial underground cavern is maintaining the stability of ground water system. In order to understand the ground water system around K-1 site, we determined the regional flow direction and level distribution of groundwater, and investigated the major geologic factors influencing their flow system. Reactivated surface along the contact between granite and gneiss, and fractures and faults along the long acidic dyke may contribute as important pathways for groundwater flow. Within K-1 site, groundwater level fluctuation is closely related to the rainfall events and injection from surface or influx water. In this project, the effect of groundwater pumping from the southern wells was examined. Based on equations relating water level drawdown to pumping rate at those wells, their pumped outflow of groundwater ranged from $80\;m^3$/day to less than $250\;m^3$/day. The modeling results with MODFLOW imply that the previous groundwater pumping at distance of 1.2 km may not affect the groundwater level variations of the K-1 site. However, continuous pumping work at quantity over $250\;m^3$/day in this area will be able to affect the groundwater system of the K-1 site, particularly along the acidic dyke.

• Journal of Soil and Groundwater Environment
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• v.17 no.3
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• pp.59-75
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• 2012

It is getting difficult to manage water resources in South Korea because more than half of annual precipitation is concentrated in the summer season and its intensity is getting severe due to global warming and climate change. Artificial recharge schemes can be a useful method to manage water resources in Korea adapting to climate change. Patent analysis enables us to prevent overlapping investment and to find out unoccupied technology. In this study, international patent trends and barriers of artificial recharge technology are analysed for patents of Korea, Japan, the United States and Europe. The four artificial recharge methods such as well recharge, surface infiltration, bank filtration and underground structures are classified as main class and the nine sub-technologies such as water intake, water treatment, injection wells, monitoring of groundwater flow, groundwater pumping, surface infiltration/soil aquifer treatment, radial collection well, iron/manganese treatment, and underground subsurface dam are classified as intermediate class. Water intake techniques are subdivided into five classifications. Total 1,281 of patents, searched by WIPS DB tool and selected after removing noisy patents, are analyzed quantitatively to evaluate application trends by year, applicant, country for each classified technologies and analyzed qualitatively to find out occupied and unoccupied technologies. It is expected that upcoming research and development project could be performed efficiently in that an avoidance plan for the similar patents and differentiation plan for the advancing patents are set up based on the quantitative and qualitative analysis results from this research.

• The Journal of Engineering Research
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• v.2 no.1
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• pp.165-174
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• 1997

It is not possible to define the earth's interior because of it complicity. However, it can be interpreted directly and/ or indirectly. Geophysics is the subject of this study. To study the possibility of construction supervision by geophysical method, geophysical prospecting was performed and studied at the SamYang pumping well area in Cheju Island, where, although underground dam was constructed, the saline water invade the pumping well area. This study focuses on the construction supervision by electrical measurements. Two electric resistivity survey lines are installed in the pumping well site, and at each line electric survey was conducted at ebb and flow tides. To increase the data quality SP (self-potential) survey was also performed. As a result the geophysical exploration methods explained the defect of construction well, and It shows that geophysical probe can be a useful tool for the construction supervision.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.37-46
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• 2012

This study was conducted to identify groundwater recharge and discharge amounts of a representative urban-rural composite area located in Yongin city, Kyounggi-do, Korea. Groundwater recharge would be affected by mainly two processes in the study area: rainfall and leakage from public water pipelines including water-supply and sewage system. Groundwater recharge rate was estimated to be 13.5% by applying annual groundwater level data from two National Groundwater Monitoring Stations to the master regression curve method. Subsequently, the recharge amounts were determined to be $13,253{\times}10^3m^3/yr$. Leakage amounts from water-supply and sewage system were estimated to be $3,218{\times}10^3$ and $5,696{\times}10^3m^3/yr$, respectively. On the whole, a total of the recharge amounts was $22,167{\times}10^3m^3/yr$, of which 60% covers rainfall recharge and 40% pipeline leakage. Groundwater discharge occurred through three processes in the composite area: baseflow, well pumping, and discharge from urban infrastructure including groundwater infiltration into sewage pipeline and artificial extraction of groundwater to protect underground facilities from submergence. Discharge amounts by baseflow flowing to the Kiheung agricultural reservoir and well pumping were estimated to be $382{\times}10^3$ and $1,323{\times}10^3m^3/yr$, respectively. Occurrence of groundwater infiltration into sewage pipeline was rarely identified. Groundwater extraction amounts from the Bundang subway line as an underground facility were identified as $714{\times}10^3m^3/yr$. Overall, a total of the discharge amounts was determined to be $2,419{\times}10^3m^3/yr$, which was contributed by 29% of artificial discharge. Even though groundwater budget of the composite area was identified to be a surplus, it should be managed for a sound groundwater environment by changing deteriorated pipelines and controlling artificial discharge amounts.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.145-155
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• 2010

Recently interest in subsea tunnels is increasing nationwide and the construction of a subsea tunnel is taking place. For the stability of such a subsea tunnel, grouting is necessary for the water barrier and reinforcement of the tunnel. In this study, therefore, it was investigated how the grouting reinforcement had an effect on the stability of a subsea tunnel located in a great depth. To this end, Hydro-mechanical coupled analyses were performed for a sensitivity analysis in terms of different grouting range, rock class, shotcrete thickness, coefficient of lateral earth pressure, grouting thickness, and pumping existence for the rock classes I, III, and V. FLAC-2D ver. 5.0 was used for the numerical analyses. It was came to the conclusion that the effect of the increased water pressure due to the water barrier of the grouting should be considered as well as the strength improved effect in designing grouting reinforcement of subsea tunnels.

• Journal of the Korean earth science society
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• v.41 no.4
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• pp.381-390
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• 2020

When a radial collector well is installed and operated for agricultural purposes, negative impacts may be observed over time due to the clogging of horizontal arms, such as reduced groundwater discharge and water quality deterioration. When radial collector well No. 2 was rehabilitated using the high-pressure impulse generation technique, the specific capacity and transmissivity were increased by 43.1 and 100.6%, respectively. In contrast, according to air surging, the specific capacity and transmissivity increased by 33.8 and 85.8%, respectively, compared to the initial rate before rehabilitation. During the operation of radial collector wells since construction, the time of well rehabilitation can be effectively determined by continuously monitoring the groundwater level and pumping rate of the radial collector wells, thereby preventing a decrease in productivity.

• Geomechanics and Engineering
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• v.13 no.4
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• pp.671-683
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• 2017

Groundwater control is a significant issue in most underground construction. An estimate of the inflow rate is required to size the pumping system, and treatment plant facilities for construction planning and cost assessment. An estimate of the excavation-induced drawdown of the initial groundwater level is required to evaluate potential environmental impacts. Analytical and empirical methods used in current engineering practice do not adequately account for the effect of the jointed-rock-mass anisotropy and heterogeneity. The impact of geostructural anisotropy of fractured rocks on tunnel inflows is addressed and the limitations of analytical solutions assuming isotropic hydraulic conductivity are discussed. In this paper the unexcavated Zagros tunnel route has been classified from groundwater flow point of view based on the combination of observed water inflow and numerical modeling results. Results show that, in this hard rock tunnel, flow usually concentrates in some areas, and much of the tunnel is dry. So the remaining unexcavated Zagros tunnel route has been categorized into three categories including high Risk, moderately risk and low risk. Results show that around 60 m of tunnel (3%) length can conduit the large amount of water into tunnel and categorized into high risk zone and about 45% of tunnel route has moderately risk. The reason is that, in this tunnel, most of the water flows in rock fractures and fractures typically occur in a clustered pattern rather than in a regular or random pattern.