• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.63-74
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• 2006

During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the full-scaled field test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM. From the full-scaled test in field, the use of in-situ CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the ground surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was the smaller than the other cases, and the absolute value was almost zero. Judging from the full-scaled field test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing the failure of the underground pipes.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.167-175
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• 2019

To effectively deal with the fire in tunnel which is mostly the vehicle fire, it's more important to suppress the fire at early stage. In urban tunnel, however, accessibility to the scene of fire by the fire fighter is very limited due to severe traffic congestion which causes the difficulty with firefighting activity in timely manner and such a problem would be further worsened in underground road (double-deck tunnel) which has been increasingly extended and deepened. In preparation for the disaster in Korea, the range of life safety facilities for installation is defined based on category of the extension and fire protection referring to risk hazard index which is determined depending on tunnel length and conditions, and particularly to directly deal with the tunnel fire, fire extinguisher, indoor hydrant and sprinkler are designated as the mandatory facilities depending on category. But such fire extinguishing installations are found inappropriate functionally and technically and thus the measure to improve the system needs to be taken. Particularly in a double-deck tunnel which accommodates the traffic in both directions within a single tunnel of which section is divided by intermediate slab, the facility or the system which functions more rapidly and effectively is more than important. This study, thus, is intended to supplement the problems with existing tunnel life safety system (fire extinguishing) and develop the remote-controlled automatic fire extinguishing system which is optimized for a double-deck tunnel. Consequently, the system considering low floor height and extended length as well as indoor hydrant for a wide range of use have been developed together with the performance verification and the process for commercialization before applying to the tunnel is underway now.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2368-2373
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• 2012

In this research, finite element method was carried out to evaluate the defomation of pipe and surface displacement for backfill of underground ficility. Various conditions for analysis were employer, including two different pipes(PE and concrete pipe), two different excavation depth(60cm and 150cm) and width(1.5D and 2D), a regular sand backfill, and four different flowable backfills. The vertical deformation of 60 cm diameter for PE was measured three times more than that of 30 cm diameter. The measured deformations for regular backfill and four flowable backfills were 0.320mm, and 0.135mm to 0.155mm, respectively. It ratio was around 40%. In case of 30cm diameter of concrete pipe, the measured vertical defomation was around 0.004mm for all the backfill materials. In case of installation depth, the effect of flowable backfill for flexible pipe is better than for rigid pipe. There is little effect on the deformation of concrete pipe with regular sand backfill and flowable backfill.

• Journal of the Korean GEO-environmental Society
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• v.6 no.4
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• pp.47-58
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• 2005

Development of underground space is conducted for various useful facility and underground structures and deep excavation technology for reclaimed area has been researched and developed. The seepage flow and behavior of phreatic line in reclaimed area was predominated by transient flow caused by tidal action. Also the soil-water characteristic relation is most important factor for transient flow analysis, therefore the research about the soil-water characteristic is strongly required. In this paper, laboratory tests (pressure cell, desiccator, and tensiometer test) and theoretical analysis were performed to investigate the soil-water characteristic such as air-entry value, metric suction, and residual water content. And the feasibility of prediction method for soil-water characteristic are presented by transient seepage analysis and comparison between analysis results and in-situ measured seepage flux in LNG TK-00 storage tank. Based on the result of laboratory and theoretical analysis, Fredlund and Xing's method provide to work out well for reclaimed ground soils. Also, the transient analysis result is more reasonable and effective for design of deep excavation work in coastal and reclaimed ground.

• Tunnel and Underground Space
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• v.29 no.4
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• pp.215-229
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• 2019

This technical note describes the current status of Finnish radioactive waste disposal project which started to construct the repository for spent nuclear waste for the first time in the world. Finland started operating nuclear power plant in 1977 and is currently operating four nuclear power plants. After detailed site surveys started in 1993, Olkiluoto was finally selected by the parliament of Finland as the site for geological disposal in 2001 followed by a construction license in 2015. If the operating license is approved by the government in the 2020s, it would be the world's first case of geological disposal. In ONKALO, a site-specific underground research facility at the site of Olkiluoto, various studies were conducted to verify the safety of the repository. Finland uses the KBS-3 disposal concept, and Korea considers a similar disposal concept because of similar rock formations. The entire process in Finland including the operation status of intermediate and low-level waste disposal, site investigation and selection stages, and the latest rock mechanics and hydrogeological studies in ONKALO are presented. Suggestions for the radioactive waste disposal in Korea is given based on the Finnish case.

• The KSFM Journal of Fluid Machinery
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• v.15 no.2
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• pp.20-29
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• 2012

The green house on the waterfront is air-conditioned by a water-source heat pump system with riverbank filtration water. In order to supply riverbank filtration water in alluvium aquifer, the riverbank filtration facility for water intake and recharge, two pumping wells and one recharge well, has been constructed. The research site in Jinju, Korea was chosen as a good site for riverbank filtration water supply by the surface geological survey, electrical resistivity soundings, and borehole surveys. In the results of two boreholes drilling at the site, it was revealed that the groundwater table is about 3 m under the ground, and that the sandy gravel aquifer layer in the thickness of 6.5 m and 3.5 m occurs at 5 m and 7 m in depth below the ground level respectively. To prevent the recharge water from affecting the pumped water which might be used as heat source or sink, the distance between pumping and recharge wells is designed at least 70 m with a quarter of recharged flow rate. It is predicted that the transfer term, the recharge water affects the pumping well, is over 6 months of heating season. Hydrogeological simulation and underground water temperature measurement have been carried out for the pumping and recharge well positions in order to confirm the capability of sustainable green house heating and cooling.

• Journal of Biosystems Engineering
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• v.39 no.1
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• pp.39-46
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• 2014

Purpose: Monitoring and control of environmental condition is highly important for optimum control of the conditions, especially in greenhouses and plant factories, and the condition is not uniform within the facility. Objectives of the study were to investigate variability in soil water content and to provide information useful for better irrigation control. Methods: Experiments were conducted in a strawberry-growing greenhouse (greenhouse 1) and a cherry tomato-growing greenhouse (greenhouse 2) in winter. Soil water content, electrical conductivity (EC), and temperature were measured over the entire area, at different distances from an irrigation pump, and on ridge and furrow areas. Results: When measured over the entire greenhouse area, soil water content decreased and temperature and electrical conductivity increased over time from morning to afternoon after irrigation. Water content decreased by distance from the irrigation pump up to 70 m and increased after that, and temperature showed an inverse pattern. Soil water contents on the ridge were lower than those on the furrow, and the differences were 10.2~18.4%, indicating considerable variability. The lowest EC were observed on the furrow and highest values were observed on the ridge. Soil water contents were less and temperature levels were greater at the window side than in the center locations. Conclusions: Selection of number and location of soil water content sensor would be the first step for better water content monitoring and irrigation control. Results of the study would provide basic data useful for optimum sensor location and control for underground greenhouse environment.

• Tunnel and Underground Space
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• v.33 no.1
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• pp.42-56
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• 2023

In deep geological disposal of high-level radioactive waste (HLW), the natural barrier must physically support the disposal facility and delay the movement of radionuclides for at least hundreds of thousands of years. To evaluate the long-term geological evolution of the natural barriers, it is essential to analyze the long-term behavior of rock joints, including the frictional healing behavior. This study aimed to experimentally analyze the frictional healing behavior of rock joints under hydro-mechanical (H-M) conditions through the slide-hold-slide (SHS) test. The SHS tests were performed under mechanical and H-M conditions for joint specimens of different roughness. In the H-M conditions, the frictional healing rate tended to increase, which was more evident in the specimens with large roughness. In addition, it was confirmed that the effect of the hydro-mechanical conditions was more significant when the effective normal stress acting on the joint surface was small. These results are expected to be used as fundamental data to understand the frictional healing behavior of rock joints in the natural barriers.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.899-915
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• 2018

In this study, in order to construct an eco-friendly advanced road transportation network, the multi-layer tunnel, which is a small-sized car road, is designed to have a height of less than 60 cm. However, the shape of the tunnel is low and the height of the traffic sign is small. In order to solve these problems, traffic sign characters were designed in three dimensions, and the possibility of applying the design of the three - dimensional sign that can obtain greater visibility than the existing signs at the same distance and the possibility verification through virtual simulation were performed. The three-dimensional sign is horizontally installed on the ceiling of the multi-layer tunnel. To be seen vertically, it is enlarged by a certain ratio by the perspective, and the width and height are enlarged. Respectively. In addition, 3D simulation was performed to verify the visibility of the stereoscopic signs when the driver ran through the stereoscopic sign design specifications. As a result of the design and experimental study, it was confirmed that the stereoscopic sign could be designed through the theoretical formula and that it could provide the driver with a larger traffic sign character because there is no limitation of the facility limit compared to the existing vertical traffic sign. Also, we confirmed that it can be implemented in the side wall by using the stereoscopic sign design principle installed on the ceiling part. It was confirmed that the design of the stereoscopic sign can be designed to be smaller as the distance that the driver visually recognizes the sperm is shorter, the height of the protrusion vertically at the lower part of the stereoscopic sign becomes higher. As a result of 3D simulation running experiment based on the design information of the stereoscopic sign, it was confirmed that the stereoscopic sign is visually the same as the vertical sign at the planned distance. Although the detailed research and institutional improvement of stereoscopic signs have not been made in Korea and abroad, it is evolved into a core technology of new road traffic facilities through various studies through the possibility of designing and applying stereoscopic signs developed through this study Expect.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.365-372
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• 2004

The purpose of this study was to implement HACCP system to foodservice of W and D elementary schools with joint-lunch management system in Kyungsan area. Steamed rice with squid was selected and Control Action, Monitoring Procedure and Control measure were identified based on HACCP flowchart to produce safe and healthy food. It was suggested that frozen squid must be thawed under the cold running city water and kept temperature below 1$0^{\circ}C$ and receiving/thawing procedure has to be done within 30 min. Raw vegetables must be washed under three-tube wash stand and whole prepreparation procedures should be done in 20 minutes. Clean and sanitize all the equipment and utensils before and after handling squid. Knives and cutting boards for vegetable and squid should be classified. Sauce for steamed rice with squid should be heated about 21 minutes to reach the temperature of 94$^{\circ}C$ before serving and internal temperature of food must be kept above 84.4$^{\circ}C$ during serving. The ideal temperature of kitchen should be remained 15∼18$^{\circ}C$. The underground water has to be excluded to minimize the risk of contamination in the foodservice facility and the prepreparation place must be separated with cooking place. Also, Personal hygiene Practice should be check in each stage. Further, additional research needs to be conducted to determine models for HACCP implementation for different menu.