• 상하수도학회지
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• 제22권4호
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• pp.405-409
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• 2008

This technical paper is proposing a sound concept in the application of the rehabilitation method of the water supply steel pipe in the large diameter ranged from 1,800mm to 3,500mm. There were conducted the experimental tests for the specimens as well as the real steel pipe of diameter 2,200mm. The water pressure ejected from nozzle tip should be at least 2,500bar to have the satisfied surface profiles required in the design criterion. The most difficult thing is to keep the water pressure at the nozzle tip as 2,500bar during the consecutive work in the interval of the work site more than 1km. It is found that the method suggested in this study is adequate method to meet the specified design criteria. The results of this study provide the useful information how to setup the equipments for the successful work. This method also provides not only the omission of the blasting process but also the effect of the budget reduction.

• 상하수도학회지
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• 제12권2호
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• pp.76-82
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• 1998

It is necessary to calculate the accurate velocity from the hydraulic model for the reliable prediction of water quality changes in water supply system. To verify the hydraulic analysis of the water supply system, fluoride was used as a tracer to calculate the travel time from the injection point to the sampling points. Results from this field experiment indicate that fluoride can be a good conservative tracer while it showed a little longitudinal dispersion along the pipe lines. And the velocity from the model was verified by these travel times and calibrated by changing the ratio of the unaccountable water. When the ratio of the unaccountable water. When the ratio of the unaccountable water was 20%, the error between the estimation of hydraulic model and the real travel time was minimum.

• 한국수자원학회논문집
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• 제55권spc1호
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• pp.1187-1195
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• 2022

관망의 세그먼트를 파악하기 위한 알고리즘을 구동시키기 위해서는 관망의 주요 구성요소들인 절점, 파이프, 및 밸브 간의 상대적인 위치 관계를 세그먼트 탐색 알고리즘의 입력정보로 준비해야 한다. 실제 지자체 관망에 존재하는 세그먼트를 보다 정확하게 파악하기 위해서는 관망 수리해석 프로그램 구동을 위해 모델링된 관망 정보를 이용하기 보다는, 모든 제수밸브가 포함된 지자체 상수도 관망 GIS/CAD 데이터베이스를 이용하여 세그먼트 탐색에 적합하게 재구성된 관망 정보를 이용할 필요가 있다. 본 연구에서는 지자체 상수도 관망 GIS/CAD 데이터를 이용하여 관망 세그먼트 탐색에 적합한 노드-파이프-밸브 간의 상대적 위치관계를 수립할 수 있는 컴퓨터 계산 알고리즘을 개발하였으며, 이를 구현할 수 있는 MATLAB 프로그램을 개발하였다. 개발된 MATLAB 프로그램을 국내 지자체 상수도 관망에 적용하여 그 실효성을 확인하였다.

• 대한기계학회논문집A
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• 제32권8호
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• pp.633-641
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• 2008

Recently, the necessity for diagnosis and management of pipes has emerged as the issue due to contamination of water supply generated by corrosion of pipes. Although inspection has been performed with industrial endoscopes, the method has limits for full diagnosis of pipes due to the lack of working range. As a solution for this problem, many locomotive mechanisms for a micro robot with endoscope functions were proposed. In this paper, we analyze the locomotive mechanism of crawling robot proposed as locomotive device for pipe inspection. Based on a mechanical modeling of motor and micro robot inside small pipe, the theoretical formula for velocity is obtained. This derived theoretical formula is demonstrated the feasibility through the comparison with experimental result. Also, we could find the most important element influencing the moving velocity of micro robot when the robot operates in small pipe. Consequently, it is expected that this study can supply useful information to design of crawling robot to move in small pipe.

• 한국재난정보학회 논문집
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• 제11권1호
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• pp.35-43
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• 2015

본 연구에서는 상수도시설물에 대해 손상단계를 기능수행과 붕괴방지로 나누고, 해외실측지진과 한반도형 인공지진에 대해 각각의 최대지반가속도에 따른 취약도 함수를 도출하였다. 손상단계 및 지반가속도를 이용하여 상수도시설물의 지진파에 따른 취약도 곡선을 도출하여 비교분석하였다. 해석결과, 도복장강관과 덕타일 주철관에 한반도형인공지진을 재하하는 경우, 해외실측지진을 재하하는 경우에 비하여 중앙값이 최소 0.1에서 최대 0.4까지 작아지는 것으로 나타났다. 본 연구에서 제안된 한반도형 인공지진을 이용한 지진취약도 곡선은 국내실정에 맞는 합리적인 내진 설계에 활용될 수 있을 것이다.

• 상하수도학회지
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• 제37권6호
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• pp.409-423
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• 2023

In this study, we analyzed how the revenue water ratio(RWR) is affected by changes in conditions of the water supply area, such as the ratio of aging pipes, maintenance conditions, and revenue water. As a result of analyzing the impact of pipe aging and maintenance conditions on the RWR, it was confirmed that the RWR could be decreased if the pipe replacement project to improve the aging pipe ratio was not carried out and proper maintenance costs were not secured. It was also confirmed that an increase in the revenue water could be operated to facilitate the achievement of the project's target RWR. In contrast, a decrease in the revenue water due to a population reduction could affect the failure of the target RWR. In addition to analyzing the causes of variation in the RWR, the calculation of estimated project costs was considered by using leakage reduction instead of RWR from recent RWR improvement project cost data. From this analysis, it was reviewed whether the project costs planned to achieve the target RWR of the RWR improvement project in A city were appropriate. In conclusion, the RWR could be affected by variations in the ratio of aging pipes, maintenance conditions, and revenue water, and it was reasonable to consider not only the construction input but also the input related to RWR improvement, such as leakage reduction, when calculating the project cost.

• 상하수도학회지
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• 제26권5호
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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.

• 대한환경공학회지
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• 제31권6호
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• pp.460-466
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• 2009

간이상수도 시스템에서 공급하는 식수는 일정한 잔류 약품(염소)량을 유지해야 하기 때문에 물과 약품의 혼합방법은 매우 중요하다. 본 연구에서는 물과 약품의 혼합방법을 최적화하기 위하여, 4가지 모델에 대한 농도분포 및 혼합지수를 구하였다. 그중 2가지 모델에 대해서는 혼합효과가 높게 나타났다. 하나는 지하수 공급 파이프 중앙에 약품을 공급하는 모델이고, 또 다른 하나는 약품공급 파이프 하류에 반원형태의 블록을 설치한 모델이다. 이러한 모델들은 유동의 확산 및 교란을 야기시켜 혼합효과를 증가시키는 결과를 가져왔다. 이와 같은 수치해석 결과는 최적의 혼합효과를 얻기 위한 시스템을 설계하는데 도움이 될 것으로 기대된다.

• 대한토목학회논문집
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• 제37권1호
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• pp.73-82
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• 2017

우리나라 상수도 기반시설 설비에 관련된 기존의 인증평가는 경제적 측면과 내구성 등 물리적 측면에 초점을 맞추어 사용되어 왔다. 그러나 경제수준이 상승하면서 상수도에 대한 위생, 보건, 안전성, 삶의 질에 대한 국민의식이 향상됨에 따라 상수도 서비스의 위생보건학적 품질향상이 요구되고 있다. 지난 5년간 국내 497개 정수장의 수질분석 자료를 고찰한 결과 pH는 5.8~8.5의 범위로 나타났다. 하지만, 현재 우리나라 수도용 자재 및 제품의 위생안전기준 공정시험방법(위생안전시험법)은 pH 7.0에서만 평가하고 있어, 실제 상수도 pH 조건에서 관내 중금속용출에 대한 기초정보가 부족하다. 이러한 배경으로 본 연구에서는 국내에서 대표적으로 사용되는 관에 대하여 pH변화가 중금속용출에 미치는 영향을 실험적으로 분석연구하였다. 본 연구 결과, pH가 낮아질수록 일부 금속의 용출정도가 증가하는 것을 확인하였다. 특히 pH 5.8일 경우, 구리재질의 관에서 Cu가 보정계수(Normalization Factor) 적용 후에도 위생안전기준을 상회하였다. 스테인레스 재질의 관에서는 Cr, Cu가, 구리재질의 이음관에서는 Cd, Pb, Cu, Zn이, 아연재질의 이음관에서는 Zn이 기준치를 각각 상회하였으나 보정계수를 적용하면 기준치를 만족하였다. 본 연구의 결과로 현행 위생안전시험법에서 pH조건을 7.0 이외의 낮은 pH 조건을 포함하는 개정의 필요성이 제안되었다. 추후 상수도관으로 사용되는 다른 종류의 관에 대한 추가 연구의 필요성도 제시되었다. 본 연구는 차후 우리나라 위생안전기준의 개정연구에 필요한 기초자료 제시에 기여를 하였다.

• 상하수도학회지
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• 제32권5호
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• pp.435-443
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• 2018

Most of aged water supply pipes have been replaced by the open cut method. However, this method has some limitations because water pipes, in many cases, are buried together with other underground facilities or are buried in the middle of high-traffic roads or in narrow alleyways where boring machines cannot be used. This research developed a pipe bursting device for small diameter pipes that enables pipe replacement without excavating the ground, by the busting of existing buried pipes followed by the traction and insertion of new pipes. As a results of examining the field applicability of the developed device, PE pipes and PVC pipes required the tractive force of 413.65~665.69 kgf and 457.43~791.35 kgf respectively, plus an additional 30 % tractive force per elbow. The proper number of bursting head was demonstrated that the connection of more than 2 heads could secure a stable bending radius of 15D. The developed device can be improved through field experiments involving various pipe types and pipe diameters, as well as presence/absence of elbow, so as to be utilized regardless of diverse variables according to the conditions of the soils surrounding existing pipes.