• Journal of the Korean GEO-environmental Society
• /
• v.17 no.11
• /
• pp.45-53
• /
• 2016

A precast panel wall system resists against the horizontal earth pressure by increasing the shear strength of ground by reinforcement connected to the panel. The application of precast panel wall system is growing to lately minimize the earth work and environmental damage caused by large cut slope and to use the limited land effectively. The ground adhered panel wall system is the construction method that has the panel engraved with natural rock shape to improve the landscape. This system is developed to complete Top-Down method, and it is possible to have vertical cut, and to adhere to in-situ ground, improve construction ability by minimizing the ground relaxation and exclusion the trench and backfill process. In this study the field tests were performed to verify the construction ability about the vertical cut and complete Top-Down process and the construction behavior of ground adhered panel wall system was analyzed by large scale loading test and measurement results during loading test.

• Resources Recycling
• /
• v.5 no.1
• /
• pp.9-13
• /
• 1996

Once-used $CO_2$-silicate bonded sand from domestic foundry is mostly discarded in a reclaimed land because of its bad collapsibility and reproduction properties. So this causes serious environmental problem. We can get 82% recovery of silica from used sand by scrubbing reclamation process in this research. When we repeat the reclamation-recycling of the foundry sand, artificial silica sand is broken down below 2-cycles, but natural silica sand does not destroyed when used repeatedly more than 10-cycles and have a good property of recycling with little change of its size.

• Journal of Environmental Impact Assessment
• /
• v.15 no.1
• /
• pp.1-12
• /
• 2006

Changes in the soil physical property and the topographic condition derived from agricultural activities like as farming activities, land clearance and cutting down resulted in environmental and economic problems including the outflow of nutrient from farms and the water pollution. Several theories on the soil conservation have been developed and reviewed to protect soil erosion in the regions having a high risk of erosion. This study was done using the USLE model developed by Wischmeier and Smith (1978), and model for the slope length and steepness made by Desmet and Govers (1996), and Nearing (1997) to evaluate the potential of the soil erodibility. Therefore, several results were obtained as follows. First, factors affecting the soil erosion based on the USLE could be extracted to examine the erosion potential in farms. Soil erodibility (K), slope length (L), and slope steepness (S) were used as main factors in the USLE in consideration of the soil, not by the land use or land cover. Second, the soil erodibility increased in paddy soils where it is low in soil content, and the very fine sandy loam exists. Analysis of the slope length showed that the value of a flat ground was 1, and the maximum value was 9.17 appearing on the steep mountain. Soil erodibility showed positive relationship to a slope. Third, the potential soil erodibility index (PSEI) showed that it is high in the PSEI of the areas of steep upland and orchard on the slope of mountainous region around Dokjigol mountain, Dunji mountain, and Deummit mountain. And the PSEI in the same land cover was different depending on the slope rather than on the physical properties in soil. Forth, the analysis of land suitability in soil erosion explained that study area had 3,672.35ha showing the suitable land, 390.88ha for the proper land, and 216.54ha for the unsuitable land. For unsuitable land, 8.71ha and 6.29ha were shown in fallow uplands and single cropping uplands, respectively.

• Journal of Environmental Science International
• /
• v.13 no.3
• /
• pp.251-262
• /
• 2004

To identify the characteristics of wastewater flow generated in treatment basins of Seogwipo-city, we selected 3 stations representing the basin and performed 7 times of field survey including 5 times in dry periods and 2 times in wet periods from Feb. 25 to May 27, 2002 for the selected stations. From the analysis of flow data measured for more than 60 days in the interval of 5 minutes and concentration data obtained from laboratory analysis, we can draw several conclusions. First, in the analysis of diurnal variation of wastewater flow for land-use types, we could find the following results: in the residential area, it is observed that wastewater flow rates rise early in the morning for the office-going hour and fall gradually and rise again after the office-leaving hour, showing typical residential wastewater flow pattern, while for the residential and commercial area flow rates rise early in the morning at the office-going hour and move up and down repeatedly within wide range and last till the office-leaving hour, which can be resulted from wastewater that is generated by tourists activated after early in the afternoon, while for the touristy area flow rates rise early in the morning and fall gradually and rise again within wide range. Second, in the analysis of temporal variation of wastewater flow for monthly, it can be observed that in the residential area, in the residential and commercial areas the flow rate of May is higher than that of Feb., March, while for the touristy area flow rate is without monthly because it reflects the movement of population, Third, in wet periods concentration of water-quality item such as SS, BOD, and COD_{cr}$ is high in the beginning of rainfall by first flush, and falls down gradually to reach the steady state, which is the level of wastewater in dry periods after the cease of storm water due to diluting effect resulting from additional runoff water through storm sewers.

• Journal of Korean Society of Forest Science
• /
• v.70 no.1
• /
• pp.77-83
• /
• 1985

By the continuous and heavy rainfall of 615 mm during 15 days, landslide disaster occurred on July 5, 1985 at a steep-sloped land in Munhyon-dong, Pusan. This landslide was sized about 50 m long at slided part and 50 m long at buried part down, 30 m in average width, and 2 m in average depth respectively. 37 human lives and the great amount of properties have been last as the result of this landslide from the steep-sloped land. Summarizing the results of this study, the national-wide plan for the steep sloped land failure control measures on the steep-sloped possible-danger places should be established in Korea.

• International Journal of Concrete Structures and Materials
• /
• v.9 no.4
• /
• pp.439-451
• /
• 2015

This study analyzed the isolation effect for a 15-story reinforced concrete (RC) building with regard to changes in the beam-column stiffness ratio and the difference in the vibration period between the superstructure and an isolation layer in order to provide basic data that are needed to devise a framework for the design of isolated RC buildings. First, this analytical study proposes to design RC building frames by securing an isolation period that is at least 2.5 times longer than the natural vibration period of a superstructure and configuring a target isolation period that is 3.0 s or longer. To verify the proposed plan, shaking table tests were conducted on a scaled-down model of 15-story RC building installed with laminated rubber bearings. The experimental results indicate that the tested isolated structure, which complied with the proposed conditions, exhibited an almost constant response distribution, verifying that the behavior of the structure improved in terms of usability. The RC building's response to inter-story drift (which causes structural damage) was reduced by about one-third that of a non-isolated structure, thereby confirming that the safety of such a superstructure can be achieved through the building's improved seismic performance.

• The Korean Journal of Ecology
• /
• v.20 no.4
• /
• pp.275-283
• /
• 1997

Vertical and temporal characteristics of desalinized reclaimed soil were analyzed from reclaimed coastal land on the western coast of Korea. Of the vertical changes during desalting, pH valuse were the lowest at the topsoil without regard to reclaimation time. The content of C1 were designated as the early period (the first 2-4 years) which decreased exponentially and the later period(the last 5-7 years) which was almost constant, from top to down. In temporal changes of the soil attributes, pH values increased for 5 years and decreased at 6 year after reclamation. Chlorine leaches more rapidly than Na does, K and Ca are constant but Mg increases as time elapsed after reclamation. Sometimes the content of Ca and K in the reclaimed soil are of higher concentration than that of the seawater after reclamation. During desallinization as exemplified by decreasing EC of the soil, Cl and Na are rapidly leached, but K, Ca and Mg are somewhat enhanced. The ration of Na/Cl in the soil equals 1 when the EC registers 5 mmho and then increases dramatically as the EC decreases. Rapid leaching of $Cl^{-}$ elicits an increasing pH valus. The electrostatic balance of the soil is achived by replacement of $Cl^{-}$ with $OH^{-}$ until stationary or until a decreasing pH value is reached again.

• Journal of Korean Society of Rural Planning
• /
• v.6 no.2 s.12
• /
• pp.43-49
• /
• 2000

Buffer zone selection technique for natural purification of livestock wastewater within a small agricultural watershed was developed using Geographic Information Systems. The technique was applied to $4.12\;km^2$ watershed located in Gosan-myun, Ansung-gun which have 20 livestock farmhouses. As a necessary data for selecting process, feedlot site map, digital Elevation Model (DEM), stream network, soil and land use map were prepared. By using these data, wastewater moving-path tracing program from each feedlot to the stream was developed to get the basic topographic factors; average slope through the paths, distance to the nearest stream and watershed outlet. To identify the vulnerable feedlots for storm event, the grid-based storm runoff model (Kim, 1998; Kim et al., 1998) was adopted. The result helps to narrow down the suitable area of buffer zone, and finally by using subjective but persuasive conditions related to elevation, slope and land use, the suitable buffer zones were selected.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.144-144
• /
• 2011

We have estimated power generation potential in Korea following the recently announced EGS protocol. According to the protocol, we calculated the theoretical potential first, which assumes 30 year operation, minimum temperature being surface temperature+$80^{\circ}C$, depth range being from 3 km to 10 km. In this new assessment the in-land area was digitized by 1' by 1' blocks, which is much finer than suggestion of the protocol (5'by 5'). Thus estimated theoretical potential reaches 6,975 GWe which is 92 times of the total power generation capacity in 2010. In the estimation of technical potential, we limited the depth range down to 6.5 km, assumed recovery factor as 0.14 and also counted for temperature drawdown factor of $10^{\circ}C$ following the protocol. Accessible in-land area excluding steep mountains, residence and industrial region, wet area and others covers 40.7% of total area. Finally, we could come up with 19.6 GWe for technical potential, which would be 56 GWe if we do not account for the temperature drawdown factor. These are important results in that we made the first potential assessment for geothermal power generation.

• Proceedings of the Korean Institute of Landscape Architecture Conference
• /
• 2007.10b
• /
• pp.127-132
• /
• 2007

Geomancy(風水, Fengshui in Chinese) is a geographic idea of the Orient that studies a piece of land(a site) to pursue the healthier and more comfortable life for people seeking a harmony with nature, and also, a practical science. Among the theoretical systems of the traditional geomancy handed down by the scriptures, the compass school(理氣論) makes researches into mountains, winds, the currents and amount of water circulation by using luo-pan(羅盤) for finding spot(穴), and it has been considered that it is the objective and logical analysis system of natural environment of selecting a good site by dividing the vitality of the ground into 12 levels of natural circulation principles and judging its direction by means of 88-direction method. In this context, researcher optimized the logic of 88-direction method by the 12-circulation system(胞胎法) of the compass school on the basis of directional theory, then after, using GIS analytical tool, researcher performed comparative analysis between the results from land suitability analysis of the subject site and the resulting value of the directional method in geomancy. The results therefrom indicated that more flexible directions and site could be chosen by applying 88-direction method. For the future research, it is required to apply wider variety of variables to the field study and more careful review of the case study with a focus on the 88-directiont method.