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공명식(Myeongsik Kong),강재모(Jaemo Kang) 한국지반환경공학회 2021 한국지반환경공학회논문집 Vol.22 No.11
도심지 지하에 매설된 열수송관 등 지하매설관이 점차 노후화함에 따라 파손에 의한 인적, 경제적 피해가 증가하고 있다. 외부로 노출되지 않아 파손 등 문제점을 즉시 확인하기 어려운 열수송관의 특징을 고려할 때, 시설물 유지관리를 통해 주기적으로 수집하는 이력정보를 기반으로 시설물의 상태를 간접적으로 확인하는 방법이 현실적이다. 본 논문에서는 열수송관 이력정보를 검토하여 파손확률과 연관성을 가지는 평가인자를 도출하고, 이를 통해 파손확률을 추정하는 방법론을 제시하고자 한다. 파손확률 추정을 위한 영향인자는 유럽의 사례, 국내 열수송관 관리기준 등을 분석해 도출하였으며, 데이터의 확보 가능성도 함께 고려하여 선정하였다. 열수송관 설치기준이 변경된 1999년을 기준으로 매설시기에 따라 2가지 파손확률 추정 함수를 달리 제시하고 관경, 용도, 관리주체 등 평가인자별 정보에 따른 가중치를 부여하여 파손확률을 보정하여 파손확률추정의 신뢰성을 확보하였다. Losses of both life and property increased from damage to underground pipe such as heat transmission pipe buried underground in downtown because pipes are gradually aging. Considering the characteristics of the heat transmission pipe, which is not exposed to the outside and difficult to immediately identify problems such as damage, it is realistic to indirectly check the condition of the facility based on the historical information that is periodically collected through facility maintenance. In this study, a methodology for estimating the damage probability was developed by examining the history information of the heat transmission pipe, deriving an evaluation factor that is related to the damage probability. The contribution factor of the damage probability were reviewed by analyzing not only the guidelines for maintenance of heat transmission pipe of advanced European countries and domestic district heating companies, but also the cases of waterworks with similar characteristics. Evaluation factors were selected by considering not only the correlation with the damage probability but also the possibility of securing data. Based on 1999, when the construction technology and standards of heat transmission pipe changed, the damage probability estimation function according to the period of use was divided into the case of being buried before 1998 and the case of being buried after 1999, and presented. In addition, the damage probability was corrected by assigning weights according to the measured data for each evaluation factor such as the diameter, use, and management authority.
공명식 ( Myeong Sik Kong ),이현동 ( Hyun Dong Lee ),강성원 ( Sung Won Kang ),이준형 ( Joon Hyung Lee ) 한국수처리학회 2013 한국수처리학회지 Vol.21 No.5
The Revenue Water(RW) rate, used for a performance assessment and a performance improvement in Korea, was calculated through top-down analysis. However, Some problems that RW rate lack credibility have been pointed out as a performance indicator. Therefore, the relationship among the RW rate, Non-Revenue Water(NRW) and the system input volume were analyzed. The results of this study showed that the RW rate varied with system input volume even if the NRW has a certain value. Furthermore, the relationship between the RW rate and real loss, using performance improvement, could not be identified. Based from the results of this study, the necessity on the application of a new performance indicator was confirmed. Moreover, the Infrastructure Leakage Index (ILI), RW rate and NRW rate were analyzed in this study. It was observed that there was a high correlation between the ILI and real loss(R2=0.9185), and NRW(R2=0.8069) represents the condition of the water supply system. Therefore, ILI was chosen as performance assessment indicator to represent the exact water loss in the water supply system.
공명식 ( Myeong Sik Kong ),이현동 ( Hyun Dong Lee ),강성원 ( Sung Won Kang ),박은주 ( Eun Zoo Park ) 한국수처리학회 2013 한국수처리학회지 Vol.21 No.4
Characteristics of leak noise frequency was built through comparison analysis of collected acoustic signals from pipeline before and after leakage. Leakage was identified at 10 points, acoustic signals were collected at 14 water supply facilities(manhole, water valve, stop valve). Investigation time was set up from 11 PM to 5 AM in order to minimize effect of white noise caused by water usage, vehicle traffic, etc. Comparing results from characteristics of acoustic signals before and after leakage showed that signal strength became weaker after repaired pipeline from the full range of frequency bands, except for some uncertain data that include heavy noise. Frequency bands indicating strong signal strength were from 200 to 2,000 ㎐, with or without leakage. As a result of analysis based on pipe material, leakage-related frequency bands were identified from 300 to 2,000 ㎐ in case of galvanized steel pipe. On the other hand, frequency bands were related less than 1,200 ㎐ if leak occurred in stainless steel pipe. Frequency analysis result according to leak point, leak noise were related from 500 to 2,000 ㎐ in case of a leak in a straight pipe, frequency bands of leak noise in joints and junction had relevance to the range of 300 to 1,200 ㎐.
공명식 ( Myeongsik Kong ),곽필재 ( Pilljae Kwak ) 한국수처리학회 2021 한국수처리학회지 Vol.29 No.6
Nondestructive diagnostic technology can be used to check for abnormalities such as metal loss, deformation, and cracks in water pipelines. However, new standards and guidelines for water pipeline maintenance must be revised or established in order to apply new technologies such as nondestructive diagnosis to the field. Herein, policies and guidelines are proposed for the diagnosis of water pipelines using nondestructive technology. Amendments are proposed to allow accurate and reliable nondestructive diagnostic technology to be applied to pipeline maintenance by reviewing the diagnostic standards and laws for water pipelines. The design standards for water conveyance, water transmission, and water distribution pipelines have been revised in order to use advanced technologies such as nondestructive technology to identify abnormalities while minimizing the impact on facilities when inspecting and diagnosing water pipelines. In addition, a revision of the detailed guidelines of the Ministry of Land, Infrastructure, and Transport according to the KS and ASTM standard is required to allow for the use of nondestructive equipment when inspecting welds. Nondestructive diagnostic guidelines that summarize the characteristics and performance of nondestructive diagnostic equipment, diagnostic procedures, and verification processes are also proposed to help managers understand the technology and easily apply it in the field when diagnosing water pipelines.