• Title/Summary/Keyword: 토질시험

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Soil Layer Distribution and Soil Characteristics on Dokdo (독도의 토층 분포 및 토질 특성)

  • Kyeong-Su Kim;Young-Suk Song;Eunseok Bang
    • The Journal of Engineering Geology
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    • v.33 no.3
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    • pp.475-487
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    • 2023
  • We surveyed the distribution of soil layers on Dongdo and Seodo of Dokdo and measured the physical properties of the soils. To investigate the distribution of soil layers, the soil depth was measured directly in accessible locations, and visual observations of inaccessible locations were carried out using drones and boats. Soil depths ranged from 3 to 50 cm, and most soil layers had depths of 10~20 cm. Based on these results, a map of the soil layer was drawn using 5 cm intervals for soil depth. To analyze the soil characteristics of Dokdo, soil samples were collected from 13 locations on Dongdo and 13 locations on Seodo, in consideration of various geological settings. According to the results of grain size distribution tests, sand contents were >75%, and soil from Seodo contained more gravel-sized particles than that from Dongdo. Using the unified soil classification system (USCS) and textural classification chart of the United States Department of Agriculture (USDA), most of the soil samples from Dokdo are classified as sand, and some are classified as loamy or clayey sand. In addition, well-graded loamy or clayey sands are more common in Dongdo, and poorly graded sands with gravel are more common in Seodo. These results are expected to be important for studying soil characteristics on Dokdo.

A Probabilistic Study on the Engineering Characteristics of Soil in Korea by the Unified Soil Classification (통일분류(統一分類)에 의한 우리나라 토질(土質) 공학적(工學的) 특성(特性)에 관한 확률론적(確率論的) 연구(硏究))

  • Chung, Chul Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.9 no.3
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    • pp.115-123
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    • 1989
  • This paper probabilisticly analyses the variance of the soil parameters on kinds of soil by conducting statistical analysis through the Unified Soil Classification System. Data used are the result of soil test which the Korea National Housing Corporation conducted in 176 sites of 74 cities throughout the country during the past 13 years from 1974 to 1986. In this paper, soil parameters such as natural water contents, specific gravity of soil particle, Atterberg limits, N-values, unconfined compression strength, compression index and shear strength parameter etc., is analysed. The result of the analysis is as follows. 1) The variance in physical properties of the soil is, when compared with coefficient of variation which is statistical variable, comparatively small. 2) The shear strength parameter is proved to be about 40% and compression index is about 32%. 3) The variance in specific gravity is 0.87-2.49% in granular soil and 0.91~5.03% in cohesive soil respectively. So, the degree of the variance is very small.

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Characteristics Analysis of Mudstone Weathered Soils in the landslide Area using Statistical Technique (통계기법에 의한 산사태발생지역 이암 풍화토층의 토질특성 분석)

  • Hwang, Eui-Soon;Chung, Dae-Seouk;Kim, Kyeong-Su;Lee, Moon-Se;Song, Young-Suk
    • Journal of the Korean Geosynthetics Society
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    • v.12 no.3
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    • pp.31-41
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    • 2013
  • In this study, the properties of mudstone weathered soils related to landslides were analyzed at the area of landslide induced by heavy rainfall in Pohang. The soil tests were carried out to the soils obtained from landslide and non landslide sites, and the soil properties were investigated. The correlation between soil properties and landslides were analyzed using statistical technique, and then the soil factors were extracted from the correlation analysis. The correlation equation which can calculate the coefficient of permeability influenced on landslides was proposed using the soil factors. As the result of analysis, the porosity and unit weight of soils from the landslide area is smaller than those of soils from the non landslide area. The soils with poor grain size distribution and loose unit weight are prone to landslides because the soils have a large void ratio and a low unit weight. The permeability of soils from the landslide area is larger than that of soils from the non landslide area. According to the result of correlation analysis, the effective grain size, the saturated unit weight and silt and clay contents are evaluated as the influence factors. These factors were considered to estimate the coefficient of permeability of mudstone weathered soils.