• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.37-42
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• 2011

Recently, the cause of flood damage has been the local torrential rainfalls rather than a total amount of yearly rainfalls. The domestic design code of drainage pump is being improved by considering the effect of local torrential rainfalls, while there is no consideration on the local torrential rainfalls in the domestic design code of bridge-deck drainage. Compared with the code of Federal Highway Administration in USA, no rational bases are specified in the domestic design code of bridge-deck drainage. This paper proposes the reasonable design guideline for bridge-deck drainage considering the effect of local torrential rainfalls.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.603-607
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• 2008

최근 이상기후현상으로 인한 가뭄과 홍수의 빈번한 발생으로 인해 인명 및 재산피해가 증대되고 있다. 특히 도시지역에서의 홍수 피해가 심각한 상황이다. 도시지역에서는 불투수 면적의 증가로 우수 유출량의 대부분을 배수관망에 의존하고 있다. 그럼에도 불구하고 현재 배수관거에 대한 관리는 미흡한 실정으로 노후되거나 부실한 배수관을 통해 토양으로 누수되거나, 관로 내에 누적된 퇴적물로 인한 관경의 축소 등으로 인해 우수가 원활하게 배제되지 못하고 지체되면서 인근지역의 침수피해를 증가시키고 있다. 이러한 피해를 경감시키기 위해서 지속적이고 신뢰성 있는 배수관 내 유황자료의 획득이 시급한 상황이다. 그러나 현재 수집되고 있는 도시지역의 배수 자료는 하천유황자료에 편중되어있으며, 배수관망 자료는 배수관망 내 유황자료의 획득이 어렵고, 배수관망 내에서 흐름의 경로 파악이 불가능 하다는 문제점을 가지고 있다. 본 연구에서는 도시 배수관망에 대한 지리정보시스템의 자료와 ubiquitous floater로부터 획득한 유황자료를 결합하여 도시 배수 관리 시스템을 구축하는 것에 목적을 두었다. 도시 배수 관리 시스템에서는 bluetooth 무선통신 기술을 이용한 ubiquitous floater를 사용하여 배수관망 내의 유속과 흐름 경로를 측정하고, 측정된 실시간 수문자료는 CDMA 무선통신모듈을 이용하여 server 컴퓨터에 전송된다. 수집된 자료는 대상유역의 지리정보시스템의 자료와 결합하여 도시 배수 관리 시스템으로 구축된다. 도시 배수 관리 시스템은 관리자가 배수관의 특성을 파악하고 문제발생시 신속하게 조치할 수 있게 도움을 줄 수 있으며, 전문적인 지식이 없는 누구나(whoever), 언제(whenever), 어디서(wherever)든 PC 앞에서 원거리에 위치한 도시 배수관망 내의 흐름 경로를 파악하고 관망 내 흐름의 현황을 파악할 수 있다.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.5
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• pp.556-560
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• 2001

Remote field eddy current testing (RFECT) with through-wall transmission characteristic is being applied to pipes ranging from small tubes of heat exchanger to natural gas supply pipelines. Cast iron pipes with nominal diameter of 100mm are used primarily as the waterline pipes. The leakage of water occurs due to defects in the pipes caused by vibration of automobiles and corrosion. But, the use of direct inspection methods such as insertion of inspection equipment inside the pipelines has been limited due to its lack of economical efficiency. Economical development of inspection equipments is possible since RFECT method can be easily employed for system integration and quantitative evaluation of both inside and outside defects. In this study, the development of underground pipeline inspection system was tarried out by using RFECT method in consideration of the characteristics of waterline network. This paper specifically describes the design and production of RFECT pipeline inspection pig using centralizer mechanism, development of remote field eddy current signal acquisition and processing software, and review of RFECT system operation procedures.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.6
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• pp.555-561
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• 2000

The remote field eddy current (RFEC) inspection was performed on the ductile cast iron pipes with nominal outer diameter of 100mm, which were machined with various shapes and sizes of defects. Ductile cast iron pipes which are used as water supply pipe have the non-uniform thickness and asymmetric cross section due to relatively high degree of allowable errors during the manufacturing processes. These characteristics of ductile cast in pipes cause the long range background noises in RFEC signals along the pipe. In this study, tile machined defects in pipes were effectively classified by the moving window average (MWA) method which eliminated the long-range noise. The voltage plane polar plots (VPPP) method was used to quantitatively evaluate the depth and circumferential degree of defects. The VPPP signatures showed that the angle between defect signature and the normalized in-phase component on the VPPP is linear to the depth of defects. The nondestructive RFEC technique proved to be capable of quantitatively evaluating the machined defects of underground water supply pipe.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.669-683
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• 2012

The water supply pipes are buried across wide range of areas, so it is hard to spot them using excavation and takes a large amount of expense. Thus, there is a high risk for direct research and application, accompanying many difficulties in implementation of them. Therefore, it is more economical and convenient to use indirect evaluation variables than direct evaluation of the buried pipes in assessing the degree of pipe deterioration. To assess the degree of pipe deterioration using the indirect evaluation variables, it should be done first to identify how and to what extent they affect the degree of deterioration. This study measured the evaluation variables for pipe deterioration using the pipe endoscope and analyzed the measurement results and the degree of impact on the pipes. In addition, this study attempted to evaluate the adequateness of the pipe deterioration evaluation using the indirect variables based on the analysis results. The evaluation variables measured through the pipe endoscope were the thickness of sediments, size of scale, degree of desquamation and condition of connections. For the indirect evaluation variables, the data such as the property data from GIS pipe network map as well as the material, diameter, age and pipe lining material of the pipe, road type, leakage frequency, average water velocity and water pressure using the leakage repair records was collected. Using the collected data, this study comparatively analyzed the indirect evaluation variables for the degree of pipe deterioration and the results from the pipe endoscope to choose appropriate variables for pipe deterioration evaluation and calculated the weights of the indirect variables on the degree of deterioration. The results showed that the order of the impact of indirect variables on deterioration was pipe age > pipe lining material > road type > leakage frequency > average water velocity with their weights of 0.45, 0.20, 0.15, 0.10, and 0.10, respectively. Conclusively, the results suggest that the measures of sediment thickness, scale size, degree of desquamation and condition of connections are appropriate for the evaluation of pipe deterioration and sufficient for the analysis of the impact of the indirect variables on deterioration.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1982-1990
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• 2010

Excepting tunnel of dorimstream - ccachimountain station section, the subway line No.2th section was build using ASSM and NATM methods because of soil pressure and land condition. The way of dealing underground water was selected without sufficient preconsideration of geographical features, ground condition, influence of lowing underground water, and long-term cost of running maintenance so that the form of undrained tunnel was build having decreased construction characteristics and technically improper elements. The form of partial drainage is very difficult to manage structures of tunnel, because water leakage, water pressure causing cracks of lining concretes and scaling are constantly happened. so partial drainage suggest that setting reinforced Anchor Bolt to prevent buoyancy and should increase center drainage way up to height of railroad. Partial drainage suggest that holey pipe(${\phi}$350mm) manhole, drainage checking pipe manhole are should be regularly dredged, when changing roadbed(gravel${\rightarrow}$concrete) drainage checking pipe manhole should be build and setting a limitation of entering underground water's quantities. Beside drainage degree in changed section of structures causing instability of structures is continuous degree. so if efficient drainage way and the patterns of flaws, problems are considered in survey, it will be expected to have a advantage condition in maintenance part.