• Journal of the Korean Geosynthetics Society
• /
• v.16 no.4
• /
• pp.67-74
• /
• 2017

In order to prevent the ground subsidence accidents caused by the occurrence of underground cavity, it is necessary to evaluate the mechanical characteristics in the relaxation zone of the underground cavity. Also, the relaxation zone including underground cavity be appropriately reinforced. This paper described analysis results based on finite element method that was conducted to analyze the mechanism for occurrence of the relaxation zone around the underground cavity. The finite element analysis applied in forced displacement was carried out to simulate the underground cavity and relaxation zone, and then there were compared with previous research results. The analysis results showed that the void distribution of soil around the underground cavity has figured out. As a result, the area of the relaxation zone could be quantitatively presented by reduction characteristics of the shear stress.

• Tunnel and Underground Space
• /
• v.26 no.4
• /
• pp.253-265
• /
• 2016

In this study, travel time data collection of mine equipments was conducted in an underground mine using a reverse Radio Frequency IDentification (RFID) system. In the reverse RFID system, RFID readers and antennas are mounted on mine equipments, and RFID tags are attached to the underground mine gallery. Indoor experiments were performed to analyze how RFID reader transmission power levels affect tag readable area and tag recognition rates. The results showed that travel time measurement become precise when the reader transmission power was reduced, however tag recognition rates were reduced. The field experiments indicated that setting the reader transmission power to 28 dBm maintained the tag recognition rate while minimizing the tracking location error. In addition, the results revealed that the reverse RFID system can be used successfully in an underground mine to collect the travel time data of haulage trucks.

• Journal of Biosystems Engineering
• /
• v.30 no.2 s.109
• /
• pp.102-109
• /
• 2005

Water consumption at the farm is up to 48 percent of water resource of South Korea while manufacturing industry's is only $9.6\%$. The area of arable land is 2,077,067 ha and 27 percent of it is used for growing fruits and vegetables using furrow or surface irrigation at the greenhouse. Surface irrigation at the greenhouse for fruits and vegetables has problems such as over watering and insufficient supply of water to the fine roots of the plant. However, the research on the new method of irrigation to save water usage is few. The characteristics of soil wetting was measured for using surface irrigation and underground trickle irrigation method where water was supplied at 10, 15, 20, and 25 cm beneath the surface ground. Followings are summary of this study. 1. The efficiency of underground trickle irrigation was expected to be as high as twice of surface irrigation such as drip watering or sprinkling. 2. This improvement could be possible by using less than $50\%$ of irrigation water than surface irrigation to supply similar amount of water near fine roots. 3. Surface irrigation causes soil compaction as deep as 20 cm below the surface ground which reduces soil porosity and root respiration ending up developing less fine roots. 4. Underground trickle irrigation can prevent overdamping in the greenhouse since it does not over wet the surface soil. At winter, the amount of agricultural chemical usage could be reduced since this irrigation method does not develop blight or crop disease from condensation of water vapor.

• Korean journal of food and cookery science
• /
• v.16 no.5
• /
• pp.425-430
• /
• 2000

This study was carried out to estimate mineral contents of some underground vegetables including potatoes, sweet-potatoes, carrots, radishes, onions, and garlics produced in Korea using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). According to the measurements, the contents of Na, Mg, Al, K, Ca, Mn, Fe, Zn, and P in Korean underground vegetables were variable depending upon producing areas and individual plants. Compared with other underground vegetables, the contents of Na in carrots and lotus roots were quite high. The contents of Cd, Ag Co. and Sr appeared to be below hazard levels. It is expected that this study can be used to calculate the mineral intake from underground vegetables.

• International Journal of High-Rise Buildings
• /
• v.3 no.2
• /
• pp.155-165
• /
• 2014

This study measured and compared the variation of ventilation rate and fan energy consumption according to various control strategies after installing wireless sensor-based pilot ventilation system in order to verify the applicability of demand-controlled ventilation (DCV) strategy that was efficient ventilation control strategy for underground parking lot. The underground parking lot pilot ventilation system controlled the ventilation rate by directly or indirectly tracking the traffic load in real-time after sensing data, using vehicle detection sensors and carbon monoxide (CO) and carbon dioxide ($CO_2$) sensor. The ventilation system has operated for 9 hours per a day. It responded real-time data every 10 minutes, providing ventilation rate in conformance with the input traffic load or contaminant level at that time. A ventilation rate of pilot ventilation system can be controlled at 8 levels. The reason is that a ventilation unit consists of 8 high-speed nozzle jet fans. This study proposed vehicle detection sensor based demand-controlled ventilation (VDS-DCV) strategy that would accurately trace direct traffic load and CO sensor based demand-controlled ventilation (CO-DCV) strategy that would indirectly estimate traffic load through the concentration of contaminants. In order to apply DCV strategy based on real-time traffic load, the minimum required ventilation rate per a single vehicle was applied. It was derived through the design ventilation rate and total parking capacity in the underground parking lot. This is because current ventilation standard established per unit floor area or unit volume of the space made it difficult to apply DCV strategy according to the real-time variation of traffic load. According to the results in this study, two DCV strategies in the underground parking lot are considered to be a good alternative approach that satisfies both energy saving and healthy indoor environment in comparison with the conventional control strategies.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.643-646
• /
• 2007

As increase of the land price at downtown area, it makes people more and more interested of improving the space utilization such as makes buildings bigger, deeper and higher. Therefore, the importance of the underground construction which is the basic principle has been increased. As constructors have to complete underground construction as soon as possible with the minimum costs, they concentrate on the whole process of underground structure. Although they makes every these efforts, construction failure still happen because of the uncertainty of the condition of soil and the unexpected danger of underground construction. To make matter worse, there are only some examples without detailed information like 'how much this breakdown damage to the construction?' so it is the anther problem that most of people doesn't recognize the economical negative impact of underground structure breakdown. This report would make people understood the importance and risk of the underground construction by showing some analysis which was assumed from the real accidents.

• Journal of the Korean Geosynthetics Society
• /
• v.21 no.3
• /
• pp.11-19
• /
• 2022

Underground environmental infrastructure and energy production facilities, which are recognized as avoidable facilities such as landfills, are emerging as an important social issue due to urbanization and economic growth. It is necessary to analyze the stability according to various ground conditions and load conditions for the construction of large-scale underground complex plants. In this paper, horizontal/vertical displacement and stress distribution according to the load condition and construction process were analyzed using finite element analysis (FEM), Based on the analysis results of various conditions, factors to be considered in the detailed design and construction of the underground complex plant were reviewed and the implications on design factors (Intermediate wall installation status, Pre-reinforcing area, etc.) for underground large space construction were derived.

• Korean Institute of Interior Design Journal
• /
• v.24 no.3
• /
• pp.197-204
• /
• 2015

This study investigated the characteristics of architectural planning in the youth training centers, which were introduced to the magazines from 2000 to 2010. The result are as followings. Firstly, the youth training centers were located mainly in general residential area, that the youth could be easily accessible. And, it were located mainly in green natural area, which is adjacent to the mountain or park. The site area of the youth training center was analyzed to approximately $10,000m^2$ below. Secondly, the placement and the form of the youth training center is divided two types, which are a single and two buildings type. A single building case is found the type of 'ㄴ' and 'ㄷ' shape, and two buildings case is found the type of 'ㄴ + ㅡ', 'opened ㅁ', 'ㅡ + ㅡ' shape. It is found mostly the type of 'ㄷ' shape. Thirdly, the youth training center is planned mostly with fifth stories above ground and three underground levels. And, sometimes it is planned a mixed-use buildings with a sports center, community center and senior welfare center. Lastly, the space of youth training center is zoned horizontally for each mass of building, which is planned the educational, cultural and sports facilities. And, it is zoned vertically some of the sports facilities and administrative support facilities in the underground, and a educational and cultural facilities on the ground.

• Structural Engineering and Mechanics
• /
• v.31 no.6
• /
• pp.679-696
• /
• 2009

The paper aims at analyzing the stress distribution around an underground opening that is subjected to non-symmetrical surface loading with emphasis on opening shapes with sharp corners and the stress concentrations developed at these locations. The analysis is performed utilizing the BIE method coupled with the Neumann's series. In order to implement this approach, the special recurrent relations for half plane were proven and the modified Shanks transform was incorporated to accelerate the series convergence. To demonstrate the capability of the developed approach, a horseshoe shape opening with sharp corners was investigated and the location and magnitude of the maximum hoop stress was calculated. The dependence of the maximum hoop stress location on the parameters of the surface loading (degree of asymmetry, size of loaded area) and of the opening (the opening height) was studied. It was found that the absolute magnitude of the maximum hoop stress (for all possible surface loading locations) is developed at the roof points when the opening height/width ratio is relatively large or when the pressure loading area is relatively narrow (compared to the roof arch radius), and contrarily, when the opening height/width ratio is relatively small or when the surface pressure is applied to a relatively wide area, the absolute magnitude of the maximum hoop stress is developed at the bottom sharp corner points.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.29 no.5
• /
• pp.43-50
• /
• 2001

This design proposal was accepted to a design competition for the improvement of Indi Youth Street, Mapo-Gu, which was held by the Seoul Metropolitan Government in June, 2000. The \`Hong-ik University District\` projected area consists of several streets, where the independent and youth culture unique to this area is blossoming-Indi music, underground arts, and historic meaning of the area as an estuary of Mapo. The site is also expected to attract many citizens and fereigners because of convenient accessibility of the new subway station to the Inchon International Airport and because of many attractions on the street- foods, music, art and people. Accordingly, the proposal set the main design concept of this project as \`the Street of Youth Culture\` considering its special and social status as well as the physical improvement of the street environment. With this concept in mind, the proposal designed the improvement of the physical conditions based on the motive of \`the Street of Youth Culture\`, having Indi/under art, Indi/ under music, Indi/under drama and Indi/multimedia animation. This design proposal of the Street of Youth Culture consist of three segments, which symbolize the millenium Youth Plaza, MultiMedia Animation Pocket and Arts Exhibition Pocket based on unity and balance. This plan has the ultimate aim of making the district one of the people\`s favorite streets in Seoul, which people love to visit again and find the vivacity of the new millennium youth culture.