• Environmental Engineering Research
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• 제18권3호
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• pp.117-121
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• 2013

For underpasses in Yeongjong Sky City business district, the guided drainage system, as a buoyancy prevention system has been designed, and is under construction. This paper investigates the safety of the guided drainage system for underpass structures being constructed in Yeongjong Sky City business district. This paper also calculates the amount of outflowing groundwater generated by the guided drainage system, and proposes alternative usages of the water. In order to investigate safety and field applicability of the guided drainage system for underpasses, characteristics of the surface flow for the area of interest have been analyzed, and the flow change of groundwater following the underpass structure construction has been evaluated using the 3-dimensional groundwater program MODFLOW. The influence of ground water on safety of the underpass structures has been calculated by FLAC2D analysis. For alternative usages for the outflowing groundwater generated by the guided drainage system, utilization methods of the outflowing groundwater in national and international resources have been researched. The amount of an outflowing groundwater to be generated in the area of interest has been analyzed, and efficient potential usages of this groundwater have been researched. When guided drainage technique is applied, the change in flow of groundwater must be evaluated and considered as safety factor relating to the buoyancy of the structure. As a result, safety factor demonstrated more than 1.2, meaning that the underpass structure is safe. The amount of subsoil drain generated by the guided drainage system was also analyzed. The quality and amount of water satisfied the standards and volume requirements, so as to make it applicable for a number of uses, such as X, Y, and Z, and should prove to be a valuable resource as the circumstances of the neighboring area change over time. These resources can be used as basic data for future urban water circulation studies, as well as generating research of alternative water usages.

• 한국터널지하공간학회 논문집
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• 제17권6호
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• pp.675-683
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• 2015

주방식 지하구조물은 주방식 채광법의 개념을 이용한 지하구조물 건설 방법이다. 주방식 공법에서 배수는 터널의 싱글쉘 개념과 유사하며, 주방식 지하구조의 장기적인 안정화를 위해서 복공 뒷면의 지하수를 배수하여 지하수위를 사전 저감시키는 방식이 유효하다. 그러나 배수공에 의한 지하수위 저감 방식은 지하 굴착시 굴착면에 지하수압이 작용하지 않거나 발생 용수량이 크지 않다면 배수공은 필요치 않게 된다. 본 연구에서는 지하 굴착시 발생용수량에 따른 배수공 적용 유무를 검토하여 주방식 지하구조에서 배수공 적용 유무를 판단하는 기준을 제안하고자 하며, 배수공 적용이 불필요한 구간에 대해서는 숏크리트를 통한 유도 배수시스템을 제안하고자 한다.

• Tuberculosis and Respiratory Diseases
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• 제81권2호
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• pp.106-115
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• 2018

Chest tube insertion is a common procedure usually done for the purpose of draining accumulated air or fluid in the pleural cavity. Small-bore chest tubes (${\leq}14F$) are generally recommended as the first-line therapy for spontaneous pneumothorax in non-ventilated patients and pleural effusions in general, with the possible exception of hemothoraces and malignant effusions (for which an immediate pleurodesis is planned). Large-bore chest drains may be useful for very large air leaks, as well as post-ineffective trial with small-bore drains. Chest tube insertion should be guided by imaging, either bedside ultrasonography or, less commonly, computed tomography. The so-called trocar technique must be avoided. Instead, blunt dissection (for tubes >24F) or the Seldinger technique should be used. All chest tubes are connected to a drainage system device: flutter valve, underwater seal, electronic systems or, for indwelling pleural catheters (IPC), vacuum bottles. The classic, three-bottle drainage system requires either (external) wall suction or gravity ("water seal") drainage (the former not being routinely recommended unless the latter is not effective). The optimal timing for tube removal is still a matter of controversy; however, the use of digital drainage systems facilitates informed and prudent decision-making in that area. A drain-clamping test before tube withdrawal is generally not advocated. Pain, drain blockage and accidental dislodgment are common complications of small-bore drains; the most dreaded complications include organ injury, hemothorax, infections, and re-expansion pulmonary edema. IPC represent a first-line palliative therapy of malignant pleural effusions in many centers. The optimal frequency of drainage, for IPC, has not been formally agreed upon or otherwise officially established.

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권3호
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• pp.1-11
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• 2023

Permeable reactive barrier (PRB) is a prominent in-situ remedial option for cleanup of contaminated groundwater and has been gaining increasing popularity in recent years. Funnel-and-gate systems, comprised of two side wings of impermeable walls and a central gate wall, are frequently implemented in many sites, but often suffers from bypassing of groundwater due to the progressive clogging of the gate wall over extended period of time. This study investigated technical feasibility of a hybrid funnel-and-gate system designed to address the flow deterioration in the gate wall. The key attribute of the proposed hybrid system is the operation of drainage units at the barrier walls and rear end of the gate wall. A conceptual modeling with MODFLOW indicated the groundwater inside the barrier was maintained at appropriate level to be guided toward the gate wall, yielding constant discharging of groundwater from the gate.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.325-335
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• 2010

A new geothermal energy source obtained from a tunnel structure has been studied in this paper. The geothermal energy is extracted through a textile-type ground heat exchanger named "Energy Textile" that is installed between a shotcrete layer and a guided drainage geotexitle. A test bed was constructed in an abandoned railway tunnel to verify the geothermal heat exchanger system performed by the energy textile. To evaluate the applicability of the energy textile, we measured the thermal conductivity of shotcrete and lining samples which were prepared in accordance with a common mixture design. An overall performance of the energy textile installed in the test bed was evaluated by carrying out a series of in-situ thermal response test. In addition, a 3-D finite volume analysis (FLUENT) was adopted to simulate the operation of the ground heat exchanger being encased in the energy textile with the consideration of the effect of the shotcrete and lining thermal conductivity.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.195.1-195.1
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• 2011

This paper presents an experimental study on a new potential geothermal energy source obtained from tunnel structures. An "energy textile", which is a textile-type ground heat exchanger, was fabricated between a shotcrete layer and a guided drainage geotextile in the tunnel lining system. To examine the long-term thermal behavior of the energy textile, the difference in temperatures of the inlet and outlet fluid circulating through the heat exchange pipe within the energy textile was monitored using a constant-temperature water bath. Daily heat exchange rate of the energy textile during cooling operation was estimated from the measured temperatures of the inlet and outlet fluid through the energy textile. The air and ground temperature was also continuously monitored. The operation of the energy textile as a ground heat exchanger was simulated using a 3D numerical CFD model (Fluent). The thermal conductivity of shotcrete and concrete lining components and temperature variation of air in the tunnel were incorporated in the model. The numerical analysis shows a good agreement with the long-term monitoring result.

• 환경영향평가
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• 제10권2호
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• pp.157-165
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• 2001

This paper presents the policy directions of total maximum daily loads(TMDL), which was recently adopted in Korea, for scientific management of water quality. The basic principles of water quality management are also discussed in this paper, along with the TMDL policy in United States as well as the previous policy in Korea. We discussed several unreasonable points out of the previous approaches, such as regulation of all point sources with equal standards, negligence of an assimilative capacity of the receiving water, and emphasis only on drinking water supply, etc.. For successful applications of the TMDL policy in Korea, the following directions are suggested: 1) the unit drainage basin for each TMDL application should be given, 2) the water body where the water quality standards should be maintained, needs to be guided, 3) the water quality parameters of TMDL should be given, 4) the technical guidances should be given for applications of water quality models, and 5) the seasonal TMDL would be allowed. In order to maximize the benefits of the TMDL policy, the local governments would need to implement the following strategies: 1) the increment of an assimilative capacity of the receiving water, 2) the effective controls of the non-point source pollution, 3) the advanced treatment of the point sources, 4) application of system optimization techniques along with effluent trade, and 5) utilization of watershed management systems.