• Title/Summary/Keyword: hardened layer

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Changes in Salinity, Hydraulic Conductivity and Penetration Resistance of a Silt Loam Soil in a Reclaimed Tidal Land (미사질 양토인 간척지 토양에서의 염류도와 수리전도도 및 관입 저항의 변화)

  • Jung, Yeong-Sang;Yoo, Sun-Ho;An, Yeol;Joo, Jin-Ho;Yu, Il-Ho
    • Korean Journal of Soil Science and Fertilizer
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    • v.35 no.4
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    • pp.207-215
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    • 2002
  • Changes in salinity, hydraulic conductivity and penetration resistance in a reclaimed tidal land reclaimed in 1986 were studied. The salinity monitoring based on electrical conductivity of saturated extract, ECe, was conducted from 1994, when the land use for experimental crop production started after tile drainage. The site was abandoned since 1999. The hydraulic conductivity was measured by a sand fill auger hole method, and the resistance was measured with a dynamic penetrometer in situ. The averaged ECe in 1994 was $33.7dS\;m^{-1}$ ranging from 25.5 to $44.8dS\;m^{-1}$, and was decreased to $25.7dS\;m^{-1}$ with large range from 0.8 to $70.3dS\;m^{-1}$ before experiment was $1.89{\times}10^{-7}m\;s^{-1}$. It increased to $1.32{\times}10^6m\;s^{-1}$ in the top 20-cm soil with large variability, while it showed $3.44{\times}10^7m\;s^{-1}$ beneath the 20-cm soil depth with less variability. The penetration resistance of the soil ranged from 0.05 to 9.99MPa. The vertical distribution of penetration resistance indicated the hardened layer was developed at the depth of 20~40 cm where the hydraulic conductivity was sharply decreased.

Heavy Metal Contamination of Soil by Wash Water of Ready Mixed Concrete (레미콘 세척수에 의한 토양의 중금속 오염)

  • Oh, Se-Wook;Lee, Bong-Jik
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.5
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    • pp.51-57
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    • 2011
  • Generally, ready-mixed concrete(RMC) gets hardened by time, so the remaining concrete in the drum should be cleaned. But if the RMC waste water generated from this is discharged to soil without any treatment, the strong alkaline elements and heavy metals affect water and ecosystem pollution. Although about 10 to 15% of water used for cleaning in the RMC factory is discharged to soil or river, the concrete report of this affecting soil pollution has not been sufficient. Hence, in this study it was analyzed the extraction of cleaning water from RMC factories all over the country and heavy metal and pH components remaining in soil when this is penetrated to various soils having water permeability. The specimens used for the experiment are weathering soil and soils having different particle size, and it is made to be penetrated to those for 24 hours while fixed thickness of the layer is maintained. Cleaning water is divided into that before deposition treatment(sludge water) and that after deposition treatment(upper water) to be penetrated into soil, and according to the result of penetrating sludge water to soil, Cu and Mn, Fe, and Zn were found to be remained over 23 to 90%. However, it is analyzed that in upper water having deposition treatment, Cu and Mn remain as 60% or more only in weathering soil.