• Geotechnical Engineering
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• v.11 no.4
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• pp.111-124
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• 1995

On development of mountaneous or hilly area, stability of cut slope should be provided to prevent undesirable landslides. When piles are used as a countermeasure to stabilize existing landslide, stabilities for both piles and slope should be simultaneously satisfied to obtain the whole stability of the slope reinforced by piles. In order to confirm the effect of stabilizing piles on slope stabilization, it is necessary to investigate the behavior of the slope, in which the piles are installed. In this paper, first, the countermeasures used commonly to control unstable slope in Korea were summerized systematically. Nezt, the behavior of piles and slope soil was investigated by instrumentation installed into a cut slope for an apartment stabilized by a row of piles. Instrumentation could present sufficient effect of piles on slope stabilization Construction works in front of the row of piles affected the displacement of piles and slope. The construction works were divided into four stages, i.e. initial cutting stage of slope, excavation stages for retaining wall and parking space, and construction of retaining wall. As the result of research, the applicability of the proposed design method could be confirmed sufficiently.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.176-176
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• 2020

본 연구는 북한의 식량난과 산림복구의 일환으로 추진되고 있는 임농복합경영의 현주소를 파악하고 북한의 임농복합경영이 가지는 대표적인 문제점이자 한국농어촌공사에서 접근할 수 있는 기술분야인 관개시설의 구축방안에 초점을 두어 해결방안을 모색하고자 하였다. 특히 임농복합경영 대상지의 경우, 산지를 개간하여 경사도 30° 이하의 경사지를 이용하고 있기 때문에 이 경우 토성이 사질 혹은 식질이 많아 보수력이 평지에 비해 크게 떨어지고 유효수분이 있는 토심도 낮기 때문에 가뭄 및 한발피해에 취약하다. 한발 시 관개를 위해 필요한 저수규모를 설정하기 위해서 강릉 안반데기와 영월 조전지구에서 산정한 단위용수량을 근거로 저수규모를 결정하였다. 계곡물이나 빗물은 자연흐름식 등의 방법으로 동력을 사용하지 않고도 집수할 수 있지만 하천이나 지하수를 퍼올려야 할 경우는 동력이 필수적으로 요구되기 때문에 대체에너지 활용을 고려하는 것이 필요하다. 따라서 임농복합경영을 위한 관개분야에 대한 대책으로 복합 취수원에 따라 하천, 지하수, 계곡, 빗물 등으로 구분하고 그에 따른 주요시설과 사업비를 산출하였다. 북한에서는 임농복합경영을 위한 경제성이 있는 규모로 50ha를 제안하고 있어 50ha규모의 임농복합경영 관수시설 부분에 대한 제안과 북한이 추진하고 있는 임농복합경영은 대부분 외부 지원에 의존하고 있기 때문에 지원의 용이성 및 가능성을 고려하여 10ha의 규모 역시 제안하였다. 50ha의 규모일 때 주요시설은 취수보, 양수장, 암반관정, 저수조, 물탱크, 송수관로, 급수관로, 급수대, 팜폰드, 둠벙, 배수로, 농로 등이며 수원공은 하천, 계곡, 지하수, 빗물이다. 동력은 태양광, 풍력으로 저수규모는 저수조에 2,000톤(40%여유수량), 팜폰드 및 둠벙에 800톤(60%여유수량)을 확보하였다. 10ha의 규모일 때 주요시설은 저수조, 물탱크, 급수관로, 팜폰드, 둠벙, 배수로, 농도 등이며 수원공은 빗물이다. 동력은 경사차를 이용한 자연흐름식 집수 방식으로 무동력이다. 본 연구는 향후 남북관계 개선시 우선 지원사업의 하나로 활용이 가능하다는데 의의가 있다. 50ha의 규모에 제시된 동인 태양광 및 풍력의 경우도 지속적인 유지관리 비용이 들지 않지만 초기 설치비가 높기 때문에 경제성이 있는 관개시스템을 개발할 필요가 있다.

• Journal of Korean Society of Forest Science
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• v.39 no.1
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• pp.1-34
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• 1978

On July 8, 1977, 432mm of precipitation which is the largest daily storm in Korea fell on the city of Anyang where a nearby suburban community of Seoul. Average storm intensities of 90mm per hour were recorded during the period from 1900~2200 hours on this date. Area of landslides triggered by this storm is about 96 hectares resulting from 1,876 places within about 12,600 hectares of the watershed studied. These hazards injured hundreds of human lives and took 122 human lives. Rail and highway systems were disrupted and about 30 hectares of rice paddies were washed away and hundreds of hectares were inundated. About 500 houses were destroyed. The objectives of this study are (a) to describe the problem areas, identifying critical factors causing the landslide hazards including earth and stone-debris avalanches, (b) suggest measures which might enhance the effectiveness of stabilization measures, and (c) also suggest the landslide and flood damage prevention methods from the point view of the upper-watershed conservation techniques in Anyang hollow-basin.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.477-487
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• 2010

In North Korea, forests were intensively degraded by forest land reclamation for food production and firewood collection since the mid-1970s. These degraded forests have to be certainly recovered for economic support, environmental protection and disaster prevention. In order to provide detailed land cover information of forest recovery project (A/R CDM), this study was focused to develop an improved classification method for degraded forest using 2.5m SPOT-5 pan-sharpened image. The degraded forest of North Korea shows various different types of texture. This study used GLCM texture bands of segmented image with spectral bands during forest cover classification. When scale factor 40/shape factor 0.3 was used as a parameter set to generate segment image, segment image was generated on suitable segment scale that could classify types of degraded forest. Forest land cover types were classified with an optimum band combination of Band1, Band2, band3, GLCM dissimilarity (band2), GLCM homogeneity (band2) and GLCM standard deviation (band3). Segment-based classification method using spectral bands and texture bands reached an 80.4% overall accuracy, but the method using only spectral bands yielded an 70.3% overall accuracy. As using spectral and texture bands, a classification accuracy of stocked forest and unstocked forest showed an increase of 23~25%. In this research, SPOT-5 pan-sharpened high-resolution satellite image could provide a very useful information for classifying the forest cover of North Korea in which field data collection was not available for ground truth data and verification directly. And segment-based classification method using texture information improved classification accuracy of degraded forest.

• Journal of Korean Society of Forest Science
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• v.13 no.1
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• pp.67-78
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• 1971

The measures of contour-terracing with sod has been executed as a major measures for hillside erosion control works for a long time in Korea. It is, however, recognized that pair terracings make a new slope-face having the more steeper degree of slope between the upper and the lower terraces on hillsides and it also does not contribute for establishing the natural vegetation-cover by penetration of pioneer seeds on the slope faces or cut-faces of hillsides. The study was therefore conducted in connection with the above problems on the cut-face having slope of $40^{\circ}$ and 1.6 meter in slope length with clay soils. Plot allocation for the experiment consists of 3 kinds of 3 replica plots having each $1.6m^2$ of slope area, i. e., the control plot with direct seeding on slopes only ($T_1$), the covering plot with the straw-mats after seeding on slopes ($T_2$) and the seeding plot after covering with the straw-mats. ($T_3$). The main results obtained may be summarized as follows : 1. Effects of the straw-mat mulchings on surface soil loss control:-The total amount of soil losses from each treatments are measured as 4,651 gr from $T_1$, 163 gr. from $T_2$ and 2,891 gr. from $T_3$ treatment respectively. (Refer to table No. 2, 3 and 4). In short, it is recognized that effect of $T_2$ treatment is compared as 28.5 times than that of $T_1$ treatment and 17.7 times than that of $T_3$ treatment respectively. Effect of $T_3$ treatment compared with $T_1$ treatment is also such recognizable as 1.6 times in control of surface soil losses on a slope face. 2. Effect of the straw-mat mulchings on soil moisture content on slopes; -Average per cent of surface soil moisture content by treatments show as 21.60 at the $T_1$, 23.04 at the $T_2$ and 22.21 at the $T_3$ treatment respectively and that of subsurface soil moisture content by treatment show as 23.81 at the $T_1$, 26.16 at the $T_2$ and 24.81 at the $T_3$ treatment respectively. The variance of soil moisture content by treatments was highly significant (Refer table No. 7, 8 and 9). 3. Effect of the straw-mat mulchings on vegetation establishment;-Average numbers of germination by treatments are counted as 237 Nos. at the $T_1$, 246 Nos. at the $T_2$ and 262 Nos. at the $T_3$ treatment plots and the vegetation coverage on ground was almost same as about 90% of covers in all treatments. This effect is more or less lower than that of surface soil erosion control. 4. Regarding the effect on surface soil erosion control, the straw-mat mulchings would be effective as a new measures for control of soil erosion on erosion susceptible lands such slope-faced bare-lands as cut-fill faces, mass-movement faces and bare hillsides.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.155-160
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• 2018

The unmanned aerial vehicle (UAV) is used in various fields, such as land surveying, facility management, and disaster monitoring and restoration because it has low operational costs, fast data acquisition, and can generate a digital surface model (DSM). Recently, the UAV has been applied to process management in construction projects. Construction projects are widely distributed not only in urban areas but also in mountainous areas and rural areas where people are rarely in traffic or in vehicles. Projects range from a few hundred meters to several kilometers long. In order to perform a reconnaissance survey, a surveying method using a global positioning system (GPS) or a total station has mainly been used. However, these methods have a disadvantage in that a lot of time is required for data acquisition. This study's purpose is to evaluate the usability of a UAV DSM for surveying a construction area. Data was acquired using the UAV and a three-dimensional (3D) laser scanner, and the DSM of the construction site was created through data processing. The UAV DSM showed accuracy to within 30 cm based on the 3D laser scanner data, and a process comparison between the two work methods was able to present the usability of the UAV DSM in the field of construction surveying. Future utilization of the UAV DSM is expected to greatly improve the efficiency of work in construction projects.

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.122-130
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• 2010

Seventy percent of Korea's national territory is covered with mountains, and the land is frequently exposed to typhoons and localized torrential downpours, particularly in July through September. For this reason, slope failure is one of the most frequent types of natural disasters in Korea. To prevent the damage caused by slope failure, the Korean government, academia and industry have strived together to develop and install a wired system for monitoring slope failures. However, conventional wired monitoring systems have been reported to have limitations, such as possible system errors caused by lightning, and the difficulties of restoration and management of the systems. To solve these problems, this research suggests a USN-based monitoring system for slope failures. First, the trend of slope measurement and USN technology was analyzed, and then the current status of damage caused by slope failures in Korea was reviewed. Next, a USN-based monitoring scenario for slope failures, incorporating both USN and slope monitoring technique, was developed. Finally, sensors were decided based on the developed scenario. It is expected that the results of this study will be utilized as fundamental data for the development of monitoring prototype systems for slope failures in the future. The development of the USN-based monitoring system for slope failures and its application in the field will also ultimately contribute to the prevention of slope failures and the minimization of related damage.

• Korean Journal of Environment and Ecology
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• v.1 no.1
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• pp.24-34
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• 1987

This study was conducted to investigate avifauna and user's effect on the avifauna in Bukhan Mountain district of Bukhan Mountain National Park. Avifauna were investigated bimonthly from April to October 1987 over four districts which were main trail and sub-trail in each valley and ridge-midslope region by line transect methods. The observed birds in Bukhan Mountain districts was 34 species and 753 individuals and these consist of 19 species for residents. 11 species for summer visitor. 2 species for passage migrant and 2 species for winter visitor. The dominant species were Parus major (22.7%), Paradoxornis webbina(10%), Parus palustris (10.8%), Pica pica (10.0%) in order. No. of species and species diversities was higher in valley region than in ridge-midslope region. No. of species, individuals and species diversities were lower in main trail of high user's density than in sub-trail. Especially avifauna in main trail was severely decreased in August in valley region in which users were concentrated. But there was no change in similarity indices according to user's intensities. Therefore avifauna protection policy such as restoration and rehabilitation of edge species along trail, user's control in valley region during breeding periods, etc., shall be made for Bukhan Mountain National Park.

• Journal of Korea Water Resources Association
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• v.51 no.4
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• pp.301-311
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• 2018

Recently, the flood inundation caused by heavy rainfall in urban area is increasing due to global warming. The variability of climate change is described in the IPCC 5th report (2014). The precipitation pattern and hydrological system is varied by climate change. Since the heavy rainfall surpassed the design capacity of the pipeline, it caused great damage in metropolitan cities such as Seoul and Busan. Inundation in urban area is primarily caused by insufficient sewer capacity and surplus overflow of river. Inundation in urban area with concentrated population is more dangerous than rural and mountains areas, because it is accompanied by human casualties as well as socio-economic damage to recover destruction of roads, brides and underground spaces. In addition, various factors such as an increase in impervious area, a short time of concentration to outlet, and a shortage of sewer capacity's lack increase flooding damage. In this study, flood inundation analysis was conducted for vulnerable areas using XP-SWMM. Also, three structural flood prevention measures such as drainage pipeline construction, detention reservoir construction, and flood pumping station construction are applied as flood damage prevention alternatives. The flood data for each alternative were extracted by dividing the basin by grid. The Spatial Compromise Programming are applied using flood assessment criteria, such as maximum inundation depth, inundation time, and construction cost. The purpose of this study is to reflect the preference of alternatives according to geographical condition even in the same watershed and to select flood defense alternative considering regional characteristics.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.710-716
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• 2011

The growth characteristics and the several component content of leaves in one year old tetraploid of Robinia pseudoacacia introduced at five site planted respectively were surveyed in Sangwon area Pyongyang, and the expand plant possibility and the leaves harvested as feed additive use of possibility in Democratic People's Republic of Korea was discussed in comparison with tetraploid of R. pseudoacacia of Yanqing area. The results were as follows (1) the length and stump diameter of annual sprouting stems at Sangwon area were smaller 50% than the tetraploiod of R. pseudoacacia stems that Yanqing area; (2) the length of sprouting stems in slope sites of Eastern (E), Western(W) and Southern(S) at Sangwon were higher 23~30% than the length that Northern slope site(N), and the diameters of sprouting stem in the slope of Eastern(E) and Southern(S) were higher 14~23% than the slope sites of Northern(N) and Western(W); (3) crude protein contents and ash contents of leaves at Sangwon were higher 40% general R. pseudoacacia and similar to the leaves that Yanqing area.