• Structural Engineering and Mechanics
• /
• 제86권6호
• /
• pp.779-791
• /
• 2023

Long-termly used in water supply, an underground concrete pipe is easily subjected to the coupled action of pressure loading and flowing water, which can cause the chemo-mechanical damage of the pipe, resulting in its premature failure and lifetime reduction. Based on the leaching characteristics and damage mechanism of concrete pipe, this paper proposes a coupled chemo-mechanical damage and failure model of underground concrete pipe for water supply, including a calcium leaching model, mechanical damage equation and a failure criterion. By using the model, a numerical simulation is performed to analyze the failure process of underground concrete pipe, such as the time-varying calcium concentration in concrete, the thickness variation of pipe wall, the evolution of chemo-mechanical damage, the distribution of concrete stress on the pipe and the lifetime of the pipe. Results show that, the failure of the pipe is a coupled chemo-mechanical damage process companied with calcium leaching. During its damage and failure, the concentrations of calcium phase in concrete decrease obviously with the time, and it can cause an increase in the chemo-mechanical damage of the pipe, while the leaching and abrasion induced by flowing water can lead to the boundary movement and wall thickness reduction of the pipe, and it results in the stress redistribution on the pipe section, a premature failure and lifetime reduction of the pipe.

• Smart Structures and Systems
• /
• 제30권5호
• /
• pp.433-446
• /
• 2022

Despite efforts to reduce unexpected accidents at confined construction sites, choking accidents continue to occur. Because of the poorly ventilated atmosphere, particularly in long, confined underground spaces, workers are subject to dangerous working conditions despite the use of artificial ventilation. Moreover, the traditional monitoring methods of using portable gas detectors place safety inspectors in direct contact with hazardous conditions. In this study, a long-range (LoRa)-based wireless safety monitoring system that features the network organization, fault-tolerant, power management, and a graphical user interface (GUI) was developed for underground construction sites. The LoRa wireless data communication system was adopted to detect hazardous gases and oxygen deficiency within a confined underground space with adjustable communication range and low power consumption. Fault tolerance based on the mapping information of the entire wireless sensor network was particularly implemented to ensure the reliable operation of the monitoring system. Moreover, a sleep mode was implemented for the efficient power management. The GUI was also developed to control the entire safety-monitoring system and to manage the measured data. The developed safety-monitoring system was validated in an indoor testing and at two full-scale water pipeline construction sites.

• 수산해양교육연구
• /
• 제22권4호
• /
• pp.604-610
• /
• 2010

Busan subway transportation system has been established a key role in the society last 20 years. However many people are suffering from hot and humid environment at subway station and platform due to deteriorated ventilation system as well as insufficient air conditioning system in existing stations and platforms. As a result, these systems require revitalization. There is about 5400tons of low temperature underground water is generated from subway stations every day. By using this method and air washer we are trying to lower the temperature. Air washer is commonly used for removing humidity but in this experiment it will be used as air precooling. This research offers result of experiment using air washer system to lower the temperature in large spaces like subway station. The experiment result has shown when L/G was the same, at condition which water spray temperature at $18^{\circ}C$ resulting inlet and outlet temperature difference larger. Also, in the same water spray temperature conditions, larger L/G condition showed a greater temperature difference. LCC evaluation of both system were shown that air washer system of using underground water will save 53% of the initial cost than refrigeration system, and save 75% of operating cost.

• 화약ㆍ발파
• /
• 제14권3호
• /
• pp.3-9
• /
• 1996

The scope of this cable works was as follows, it was drilled two shafts, NO. 1 shaft (${\phi}6.8m{\times}31m$), NO.2 shaft (${\phi}6.8m{\times}33m$), ) and it was connected two shaft in Tunneling. The first, it was needed to investigate the surey of influenced of vibration and noise by blastig to near by housing structure. 2nd, it was essential to decide the boundary line of influenced for agriculture water and portable water, by draw down of underground water. Blasting works has been done successfully without any problem, but by draw down of underground water, with in 250m level from #1 shaft, agriculture well drilled 8 place and portable water well drilled 7 place for near by farmers.

• Korean Journal of Geomatics
• /
• 제1권1호
• /
• pp.75-83
• /
• 2001

Due to the fast industrial growth and unplanned urban underground development in Korea, systematic management for water lines could not be accomplished. Unsystematic water line management has resulted in difficulty in finding the exact location and the age of the lines, which has the potential of leading to a disastrous situation. The objective of this study is a development of safety management system for water lines using GIS. This system is constructed to easily estimate water line deterioration by the geographic output system on it, search for damaged objectives near the surrounding area in a situation of destruction, and offer the emergency information by which one can quickly take action. Also, it is constructed to prevent accidents from occurring during work by presenting underground utilities and states of work.

• KIEAE Journal
• /
• 제16권6호
• /
• pp.109-114
• /
• 2016

Purpose: The underground air is the warm air discharged from the porous volcano bedrock 30-50m underground in Jeju, including excessive humidity. The temperature of the underground air is $15-20^{\circ}C$ throughout the year. In Jeju, the underground air was used for heating greenhouses by supplying into greenhouses directly. This heating method by supplying the underground air into greenhouses directly had several problems. The study was conducted to develop the heat pump system using underground air as heat source for resolving excessive humidity problem of the underground air, adopting the underground air as a farm supporting project by Ministry of Agriculture, Food and Rural Affairs(MAFRA) and saving heating cost for agricultural facilities. Method: 35kW scale(10 RT) heat pump system using underground air installed in a greenhouse of area $330m^2$ in Jeju-Special Self-Governing Province Agricultural Research & Extension Services, Seogwipo-si, Jeju. The inlet and outlet water temperature of the condenser, the evaporator and the thermal storage tank and the underground air temperature and the air temperature in the greenhouse were measured by T type thermocouples. The data were collected and saved in a data logger(MV200, Yokogawa, Japan). Flow rates of water flowing in the condenser, the evaporator and the thermal storage tank were measured by an ultrasonic flow meter(PT868, Panametrics, Norway). The total electric power that consumed by the system was measured by a wattmeter(CW240, Yokogawa, Japan). Heating COP, rejection heat of condenser, extraction heat of evaporator and heating cost were analyzed. Result: The underground air in Jeju was adopted as a farm supporting project by Ministry of Agriculture, Food and Rural Affairs(MAFRA) in 2010. From 2011, the heat pump systems using underground air as a heat source were installed in 12 farms(16.3ha) in Jeju.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2004년도 학술.기술논문발표회
• /
• pp.91-95
• /
• 2004

Utilization of underground construction if increased by the large size ＆ skycraperlization of building recently. Therefore. waterproof dependence of underground construction is risen. However, water leakage was happened by rupture by concrete conduct, drying shrinkage. form tie. In underground environment soil class, degradation of waterproofing is showing to corrode by oil. An odious smell by oil, promotion evil of reinforcing rod corrosion, declination of durability can happen. Then, practical un degree of underground spare becomes low, Because oil or water permeates by construction by degradation to waterproof class corrode by oil, is considered to affect evil durability of construction.

• 한국화재소방학회논문지
• /
• 제15권4호
• /
• pp.57-63
• /
• 2001

최근 지하공동구내의 화재가 자주 발생, 도시의 기능이 마비되는 등 국민생활을 위협하고 있으며, 막대한 재산 및 인명피해를 초래하고 있다. 지하공동구 화재로 인한 조기진압은 소방법의 연소방지설비 기준에 적용하였을 경우 화재진압시 많은 문제가 있다고 판단된다. 지하공동구의 연소방지설비 중에는 여러 방식을 적용할 수 있으나, 본 연구에서는 물을 이용한 방식 중에 국내 및 소방법에서 적용되지 않고 있는 워터 미스트(water mist)방식에 대해서 연구하고 그 설치 방안을 제시하고자 한다.

• 한국건축시공학회지
• /
• 제5권4호
• /
• pp.165-171
• /
• 2005

Nowadays, a source of all water, which has been spent by a lot of people, is the rainwater The rainwater is directly relating human being' life. According to how to use rainwater. human being' life is abundant or poor. Due to the lack of underground filtration quantity, the water circulation of the city is discontinued and the underground ecosystem is destroyed. This study suggest that the unused underground space of building and temporary structure can be used into rainwater storage tank in the facility to use rainwater. Moreover, in this study, while the building is constructed, It is showed that the water used in construction can be replaced in the rainwater.

• Spatial Information Research
• /
• 제16권2호
• /
• pp.263-278
• /
• 2008

최근 지방자치단체들은 u-City 사업구상을 통해 지능형 지하시설물 관리를 계획하고 있지만, 지하시설물의 지능화를 위해서는 막대한 재원이 소요되므로 단계적 접근이 필요하다. 따라서 본 연구의 목표는 센싱기술 개발의 우선순위가 높은 상수도 모니터링 항목을 도출하여 기술적 실현가능성과 경제적 파급효과가 높은 킬러어플리케이션을 발굴하는데 있다. 이를 위해 상수도 업무분석, 심층면담조사, 지자체 설문조사, 전문가의견조사 등을 통해 최종 모니터링 항목을 도출하였다. 분석 결과 유량계 유량, 상수관로 누수 균열, 상수관로 압력, 정수장 유량에 대한 모니터링 기술개발의 우선순위가 높게 나타났다. 이러한 연구결과는 상수도 시설물 관리의 실제적인 수요와 우선순위를 도출하고 평가하였다는데 의의가 있으며, 향후 지하시설물 지능화 관련 기술개발의 방향성 제시에 기여할 것이라 기대된다.