• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.157-170
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• 1999

A new design technique is presented to stabilize cut slopes in cohesive soils by use of piles. The design method can consider systematically factors such as the gradient and height of slope, the number and position of pile's rows, the interval and stiffness of piles, etc. The design method is established on the basis of the stability analysis of slope with rows of piles. The basic concept applied in the stability analysis is that the soil across the open space between piles can be retained by the arching action of the soil, when a row of piles is installed in soil undergoing lateral movement such as landslides. To obtain the whole stability of slope containing piles, two kinds of analyses for the pile-stability and the slope- stability must be performed simultaneously. An instrumentation system has been installed at a cut slope in cohesive soil, which has been designed according to the presented design process. The behavior of both the piles and the soil across the open space between piles is observed precisely. The result of instrumentation shows that the cut slope has been stabilized by the contribution of stabilizing effect of piles on the slope stability in cohesive soil.

• Journal of Environmental Science International
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• v.29 no.5
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• pp.519-529
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• 2020

The purpose of this study was to provide basic health care data for the climate aspects of park re-cultivation by evaluating air ions according to the type of vegetation in the valley and upper slopes of the mountain park. Simple negative or positive air ions were expected to show the same tendencies, so they were analyzed in terms of correcting the air ion index. By analyzing the air ions according to the topography, it was found that valley > slope in terms of the air ion index. When analyzing air ions according to tree species, we found that evergreen conifers in the valley > the deciduous broad-leaved trees in the valley > the evergreen conifers in the slope = the deciduous broad-leaved trees in the slope. For DBH(Diameter at breast height), the valley large pole > slope large pole > slope medium hard wood, while crown density was analyzed as valley dense > slope dense> valley proper > slope proper. Layered structure analysis showed that the multi-layer structure of the valley > multi-layer structure of the slope = the single-layer structure of the valley > the single-layer structure of the slope. The correlation coefficient was determined according to vegetation type and air ion index in the order of DBH > crown density > layer structure > geomorphic structure. In this study, limits exist except for ridge line, valley, and slopes in urban mountain parks. Therefore, analysis should be made considering both topographical structure and various vegetation types in future studies of air ions.

• Journal of the Society of Disaster Information
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• v.14 no.4
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• pp.421-429
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• 2018

Purpose: This study conducted a slope stability study considering changes in the ground water level due to rain phenomena and the duration of rainfall, that is for the purpose of analyzing the stability of the slope surface of the cut section, seepage numerical analysis is performed by height of slope and rainfall accident, and the characteristics of rainfall was applied reasonably in order to determine the slope change during rain by analyzing rainfall and rainfall pattern due to climate change. Results: As a result of numerical analysis of stability for slope composed of the granite weathered soils according to the characteristics of rainfall(Uniform Rainfall, US Army Corps., Huff's method - 1/4, 4/4), Conclusion: The higher the slope, the smaller the safety factor of the slope, the smaller the elevation of the ground water level as the rainwater seepage does not reach the underground water level. In addition, the ground water level was assessed to be rose significantly in condition of case 3 Huff's method - 1/4, rain pattern with the largest initial rainfall duration, and the safety factor was analyzed to be small.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.6
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• pp.72-82
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• 2000

Many lot of books introduce the methods to calculate the time of concentration, and these are described as various forms of formulas. There are few formulas appropriate for our basin characteristics Therefone, there are problems to make excessive or less estimation when these formulas are used. To solve these problems, comparison of formulas and sensitivity analysis for them were made with converting parameters. Finally, Time of concentration was estimated to derive Application limits for 3 watersheds by standardized formulas. In the case of input parameters analysis, SCS formula has the highest value by the length, Kerby by the height and SCS by the slope, respectively, while Kraven formula has the lowest value among them. Concerning the relative sensitivity by Taylor series, the time of concentration showed the constant effect while increasing of the length and slope, and the length was more sensitive than the slope in parameters. Finally the standardization formula developed in this study was applied to derive application limits for 3 watersheds(total 17 subbasins). In this case, Rziha(8 subbasins) and SCS(9 subbasins) formulas were the most similar to observed data of total 17 subbasins respectively. Application limits were about 300~500$\textrm{km}^2$ area, 30~60km length and under 0.01 slope for Rziha formula and about 100~200$\textrm{km}^2$ area, 10~30km length, and over 0.01 slope for SCS formula, respectively.

• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.337-358
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• 2006

The field survey was conducted weekly from April to October in 2004 and 2005 on the sites along the 5.16 road. Sampling sites were made every 100 m height starting from 250 m altitude of both sides of Mt. Halla along 5.16 Road, which crosses the mountain from North to South. Totally 31,698 individuals of 76 species belonged to 25 families were collected. It was July that showed the largest number of species, as 48 species in the northern sloper 42 in the southern slope, and 22 at the highest site (at an altitude of 750 m), while it was April that showed the smallest as 17 species, 15 and 5, respectively. As for monthly fluctuation, the northern slope and the highest site reached their top in August, whereas it was June in the southern slope. In the analyses of similarity (chord distance) of any pair of temporal communities, the closest pair was between June and July in the northern slope area, between July and August in the southern slope and between July and September at the highest site, respectively.

• Journal of the Korean Institute of Rural Architecture
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• v.2 no.1
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• pp.101-112
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• 2000

Green environment is most important factor to human being taking a side view of psychological aspect. But, as the civilization progresses rapidly, the green environment decreases. At present, various environmentally friendly methods are developed to prevent the ill effect of the concretes. n this study, Ecostone retaining wall method, which is a kind of environmentally friendly block, are used for verifying the application to the slope stability and protection of rural hosing. In case of rural hosing and structure, the height of the slope is not high and additional loading doesn't act on the slope except the gravity loading of housing and structure. From the result of the stability analysis of Ecostone, 3m to 7m Ecostone retaining wall can have an equivalence capacity comparing with the concrete retaining wall. Therefore, Ecostone method can apply to retaining wall with the structural safety and environmentally friendly aspect using the plants and vegetation.

• Geomechanics and Engineering
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• v.14 no.3
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• pp.257-269
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• 2018

Analysis of slope stability failures, as one of the complex natural hazards, is one of the important research issues in the field of civil engineering. Present paper adopts and investigates four soft computing-based techniques for this problem: Patient Rule-Induction Method (PRIM), M5' algorithm, Group Method of data Handling (GMDH) and Multivariate Adaptive Regression Splines (MARS). A comprehensive database consisting of 168 case histories is used to calibrate and test the developed models. Six predictive variables including slope height, slope angle, bulk density, cohesion, angle of internal friction, and pore water pressure ratio were considered to generate new models. The results of test studies are used for feasibility, effectiveness and practicality comparison of techniques with each other, and with the other available well-known methods in the literature. Results show that all methods not only are feasible but also result in better performance than previously developed soft computing based predictive models and tools. It is shown that M5' and PRIM algorithms are the most effective and practical prediction models.

• Proceedings of the KSEG Conference
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• 2002.04a
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• pp.61-73
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• 2002

Daegok dam is Concrete Face Rockfill Dam(C.F.R.D) of which 52m height, 190m length, that construction in beneath 306, Chanjeon-Ri, Dudong-Myeon, Ulju-Gun, Ulsan Metrocity. Left slope excavation of spillway have related to Daegok dam construction are developing crack in Sta. No. 1~2, EL. 134~137m after 67.0mm rainfall from 2000. 7. 23. 13:00 to 7. 24. 04:00. Surface geological survey and slope stability investigation with stereographic projection method in order of slope stability establishment. Partial supplement excavation and SSL. P. C. Anchoring method is able to pre-stressing are think about unstable element after excavation. This slope stability establishment is very successfully completion.

• Journal of Korean Society of Forest Science
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• v.71 no.1
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• pp.50-54
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• 1985

The effect of relations parameters on the declination gradient of trees was studied in natural forest of Quercus variabilis, Quercus ${\times}$ grosseserrata, Quercus aliens, and Quercus dentata grown at various slope gradient. The declination gradients of trees were effected by the species, slope gradient, and direction of slope, but not effected by density and height in all species. The species shows a superior factor effecting declination gradient of trees compared with other relations parameters, and next effective factor was slope gradient. Especially in all of slope gradient, the declination gradient of Quercus ${\times}$ grossesserrata was highest.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.83-91
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• 2002

Stability analysis of rocky embankment slopes is done by both the limit equilibrium method and the finite difference method. The height or the rocky embankment is approximately 40 m and the side slope is 1 vertical to 1.5 horizontal. The cohesion and internal friction angle of rock debris are assumed zero and 43$^{\circ}$, respectively. For finite difference analysis, strength reduction method is used to calculate the saft factor of the slope. As a result, the safety factor of the slope is discovered to be 1.4 by using either methods. Considering that the design criteria of the safety factor is 1.3, it can be judged that the rock fragments embankment slope is in a stable state.