• The Journal of Engineering Geology
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• v.34 no.2
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• pp.193-206
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• 2024

A standard slope stability analysis was undertaken for new railway sections, based on the slope of sedimentary rock layers and filling material (sand), to evaluate the stability of the cut-off slope in the section passing through a zone of sedimentary rock. The stability analysis was undertaken during the dry and rainy seasons, accounting for earthquake occurrence, based on slope design criteria. It was found that if the slope of the sedimentary rock formation was <10°, the effect on the safety rate of the cut-off slope was insignificant. Furthermore, a slope relief of 1:1.0 or more should be applied with slopes of 10~20°, and 1:1.2 or more with >20°. This study provides an important reference for evaluation of slope stability when railway and road construction is undertaken in areas of sedimentary rock.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.3
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• pp.4449-4461
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• 1977

Subsurface Drinage Problems arise from many causes. Flatland tends to be poorly drained, particularly where the subsoil permeability is low. There are many wet areas, however, where there is no evident connection between the area of seepage, or a high water table, and the topography of the site. High water tables may occur where the soil is either slowly or rapidly permeable, where the climate is either humid or arid, and where the land is either sloping or flat. This study is to bring light on subjects relating to increasing yield of crop and possibility of double crops a year in water logging paddy fields. Obtained results are briefly summarized as follows: 1. Effect of crop-yield in the plot A resulted 20.2 percent higher than the ordinary plot with yield of brown rice. 2. Possibility of double-crops a year is investigated. Effect of the barley production of the test plot resulted 168.2 percent higher than the other uplands near test plot with the yield of 1977 production and it is 3.8 percent higher compare with the yearly yields. 3. Decreasing depth of water level was measured 23.9mm per day and 14.3mm per day at the test plot and ordinary plot respectively and the amounts of subsurface drainage measured 30mm to 35mm per day. It is required that the relief well should be controled carefully and adequately. 4. Mean depth of ground water levl was measured 0.4∼0.5m regardless the width of corrugated pipe. It is significantly lowere than the ordinary plot(0.15∼0.20m) 5. The ground temperature of the test plot is higher 1 degree of centigarade or more than the ordinary plot and soil moisture content of the ordinary plot is higher 12.4∼27.8 percent than the plot reversely. There should be a relationship between rising of ground temperature and soil moisture.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.61-66
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• 1970

This study examined the morphology and physical and chemical characteristics of the Changpyeong series developed on gently sloping to rolling relief on dissected old paddiplains and terraces. This soil has dark brown silty clay loam A horizons, very thick dark red to red silty clay or clay Bt horizons, and C horizons of old alluvial materials frequently with strongly weathered round cobbles and pebbles. It is strongly acid with a low organic matter content, relatively low in cation exchange capacity, but with relatively high base-status based on amount of extractable cations. There is no obvious changes in particle size distribution with depth and textural B horizons probably have not been formed by podzolization but formed by mechanical movement of clay. This soil is classified as Typic Hapludalfs in USDA 7th approximation and Brunic Luvisols in FAO classification system.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.1
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• pp.1-8
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• 1973

This study examined the morphological, physical and chemical characteristics of the Yesan and the Songjeong series derived from residuum of the granite developed on gently sloping to rolling relief in Honam reclamable land Area. The results of this study are summarized as follows. 1. The morphological characteristics. In the Yesan series, the surface soils(Ap horizons) are brown to dark brown sandy loam. The subsoils(B horizons) are yellowish red to red sandy clay loam to sandy loam and the soil profile development is weak. The Songjeong series, the surface soils (Ap horizons) are washed by erosion, so the subsoils are revealed on the surface, and these are dark red silty clay loam. The subsoils (B horizons) are red silty clay loam and thin clay cutans are formed on the ped faces of the structure. The substrata of two soil series are deeply weathered granitic saprolite. 2. The physical and chemical characteristics. The distribution of clay content tends to increase from surfaces to subsoils with depth gradually. On the Yesan series, the content of clay is less than 18%, soil pH (6.0 in the surface-soil, 4.5-5.0 in the subsoil), the content of organic matter (1.8% in the surface soil, 0.1~0.4% in the subsoil), available phosphate (40 ppm), the cation exchange capacity(4~8 me/100 gr) are very low, and the base saturation (57.8% in the surface soil, 46.3% in the subsoil) is moderate. On the Songjeong series, the content of clay is 30~40%, pH (5.7-6.0), the content of in organic matter (1.25% in the surface soil, 0.1~0.4% in the subsoil), available phosphate(4 ppm), the cation exchange capacity(6.2 me/100 gr in the surface soil, 2~6 me/100gr in the subsoil) are very low, and the base saturation(28.1% in the surfacesoil, 16~23% in the subsoil) is also low. 3. The Yesan and Songjeong series are for med under a temperate humid climate, and classified as Red Yellow Soils in the old classification system. According to U.S.D.A. 7th approximation the former belongs to Typic Dystrochrepts in Inceptisols, and the latter, Typic Hapludults in Ultisols.