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  • Title/Summary/Keyword: SOIL CHARACTERISTICS

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An Experimental Study on the Quality Characteristics of Soil-Cement for Deep Mixing Method Using Carbon Capture Minerals(CCM) (이산화탄소 포집광물을 활용한 심층혼합처리용 Soil-Cement의 품질 특성에 관한 실험적 연구)

  • Jung, Woo-Yong;Ju, Hyang-Jong;Oh, Sung-Rok;Choi, Yun-Wang
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.2
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    • pp.153-160
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    • 2020
  • In this study, the optimum ratio of soil-cement was derived to utilize carbon capture minerals(CCM) as soil-cement for deep mixing method, quality characteristics of soil-cement mixed with carbon capture minerals were evaluated. The CCM is generated in the form of a slurry, and as a result of evaluating water content, it was found to be about 50%. Accordingly, the water content of CCM was removed in the unit water of Soil-cement mix. As a result of field mixing of soil-cement using CCM on field soil, it showed that the design allowable bearing capacity was satisfied by showing 3.0MPa or more as of 28 days of age. As a result of the hazard verification of carbon capture minerals, 0.055mg/L of Cu was detected, but satisfies the acceptance criteria, and no other harmful substances were eluted.

Characteristics of accumulated soil carbon and soil respiration in temperate deciduous forest and alpine pastureland

  • Jeong, Seok-Hee;Eom, Ji-Young;Park, Ju-Yeon;Lee, Jae-Ho;Lee, Jae-Seok
    • Journal of Ecology and Environment
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    • v.42 no.1
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    • pp.20-29
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    • 2018
  • Background: For various reasons such as agricultural and economical purposes, land-use changes are rapidly increasing not only in Korea but also in the world, leading to shifts in the characteristics of local carbon cycle. Therefore, in order to understand the large-scale ecosystem carbon cycle, it is necessary first to understand vegetation on this local scale. As a result, it is essential to comprehend change of the carbon balance attributed by the land-use changes. In this study, we attempt to understand accumulated soil carbon (ASC) and soil respiration (Rs) related to carbon cycle in two ecosystems, artificially turned forest into pastureland from forest and a native deciduous temperate forest, resulted from different land-use in the same area. Results: Rs were shown typical seasonal changes in the alpine pastureland (AP) and temperate deciduous forest (TDF). The annual average Rs was 160.5mgCO2m2h1 in the AP, but it was 405.1mgCO2m2h1 in the TDF, indicating that the Rs in the AP was lower about 54% than that in the TDF. Also, ASC in the AP was 124.49MgCha1 from litter layer to 30-cm soil depth. The ASC was about 88.9MgCha1, and it was 71.5% of that of the AP. The temperature factors in the AP was high about 4C on average compared to the TDF. In AP, it was observed high amount of sunlight entering near the soil surface which is related to high soil temperature is due to low canopy structure. This tendency is due to the smaller emission of organic carbon that is accumulated in the soil, which means a higher ASC in the AP compared to the TDF. Conclusions: The artificial transformation of natural ecosystems into different ecosystems is proceeding widely in the world as well as Korea. The change in land-use type is caused to make the different characteristics of carbon cycle and storage in same region. For evaluating and predicting the carbon cycle in the vegetation modified by the human activity, it is necessary to understand the carbon cycle and storage characteristics of natural ecosystems and converted ecosystems. In this study, we studied the characteristics of ecosystem carbon cycle using different forms in the same region. The land-use changes from a TDF to AP leads to changes in dominant vegetation. Removal of canopy increased light and temperature conditions and slightly decreased SMC during the growing season. Also, land-use change led to an increase of ASC and decrease of Rs in AP. In terms of ecosystem carbon sequestration, AP showed a greater amount of carbon stored in the soil due to sustained supply of above-ground liters and lower degradation rate (soil respiration) than TDF in the high mountains. This shows that TDF and AP do not have much difference in terms of storage and circulation of carbon because the amount of carbon in the forest biomass is stored in the soil in the AP.

Changes in Soil Water Content and Drainage Characteristics with Superabsorbent Polymers Amendment (고흡수성 수지 처리에 따른 토양 수분 함량과 배수 특성 변화)

  • Yun, Tae-Kang;Son, Young-Hwan;Park, Jae-Sung;Kim, Dong-Geun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.58 no.3
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    • pp.47-56
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    • 2016
  • Superabsorbent Polymers (SAPs) are hydrophilic synthetic polymers which could absorb water by hundreds of their own weight. They are used for multiple purpose including hygienic goods, soil conditioners, and hospital supplies. It is necessary to investigate the standard of their use including the amendment rate for soil application in agricultural fields. It is also important to understand their effects on the soil water content and engineering characteristics. The objective of this study is to find the water absorbing capacity and reusability of SAPs, and the characteristics of water release and effect of them on soil water content and engineering characteristics. In the result, SAPs per unit weight (1 g) used for this research could absorb about 200 g of water in max. The water absorbing capacity decreased after SAPs were used repeatedly. Released water of SAPs could provide the soils with about 9 % of the soil water content. Soil water content increased with decreasing distance from the SAPs. The distance of release was spreaded out with increasing water absorbed of SAPs. Finally, when a drainage and the capacity of soil water content were considered, it is recommended to amend the SAPs with soil by less than 0.25 %.

Desorption Kinetics and Removal Characteristics of Pb-Contaminated Soil by the Soil Washing Method: Mixing Ratios and Particle Sizes

  • Lee, Yun-Hee;Oa, Seong-Wook
    • Environmental Engineering Research
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    • v.17 no.3
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    • pp.145-150
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    • 2012
  • Pb-contaminated soil at a clay shooting range was analyzed by the sequential extraction method to identify metal binding properties in terms of detrital and non-detrital forms of the soil. Most of the metals in the soils existed as non-detrital forms, exchangeable and carbonate-bound forms, which could be easily released from the soil by a washing method. Therefore, the characteristics of Pb desorption for remediation of the Pb-contaminated soil were evaluated using hydrochloric acid (HCl) by a washing method. Batch experiments were performed to identify the factors influencing extraction efficiency. The effects of the solid to liquid (S/L) ratio (1:2, 1:3, and 1:4), soil particle size, and extraction time on the removal capacity of Pb by HCl were evaluated. Soil samples were collected from two different areas: a slope area (SA) and a land area (LA) at the field. As results, the optimal conditions at 2.8 to 0.075 mm of particle size were 1:3 of the S/L ratio and 10 min of extraction time for SA, and 1:4 of the S/L ratio and 5 min of extraction time for LA. The characteristics of Pb desorption were adequately described by two-reaction kinetic models.

An Estimation of Wedge Type Removable Soil Nailing System Using by Laboratory Tests (실내역학 실험을 통한 쐐기형 제거식 쏘일네일링 공법의 적용성 평가)

  • Park, Si-Sam;Han, Yeon-Jin;Heo, Seong-Jun;Yoon, Myung-June;Kim, Hong-Taek;Park, Ju-Seok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.1330-1333
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    • 2009
  • The soil nailing method had used in variable construction field because of construction convenience and reinforcement effect. Especially, the removal soil nailing method is useful support system in vertical excavation. In this study, to develop the wedge type removable soil nailing method for improvement of the removal soil nailing method. Because of the reinforcement materials is most important in soil nailing method, to evaluate the mechanical characteristics during laboratory strength test in this study. To conduct bond strength test of deformed bar combined with a wedged screw inside plastic fixed socket for evaluate the strength characteristics of wedge type removable soil nailing method and evaluate the strength characteristics of fixed socket based on laboratory tests.

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Analysis of Catena on Representative Soils derived from Granite and Granite Gneiss

  • Sonn, Yeon-Kyu;Cho, Hyun-Jun;Hyun, Byung-Keun;Chun, Hyen-Chung;Shin, Kook-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.4
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    • pp.255-261
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    • 2015
  • Soil catena can be characterized by some properties, such as drainage levels and soil textures. Characteristics of soil catena are different drainage levels from a summit to the direction of gravity and similar soil textures. Therefore this study was performed GIS (Geographic information system) and statistical analyses using perimeters from soil series in order to characterize quantitatively and objectively soil distributional properties in Korea. The total of 16 soil series from representative granite and granite gneiss originated soils were selected among inland soils from detailed soil maps (1:25,000 scale) in Rural Development Administration (RDA) and analyzed. After the detailed soil maps were merged by soil series unit, perimeters were measured from one soil series to neighboring soil series using functions of table join, merge, dissolve, buffer, and clip in ArcGIS (10.1). The covering ratio of each soil series unit was calculated from neighboring perimeters by soil series and applied to clustering analysis. Soils that were analyzed were the total of 16 soil series; 7 of sandy loam and 9 of clay loam. As a result, analyzed soil series adjoined complicatedly such as Hyocheon series adjoined 26 series and Jisan did 276 series. The results of the clustering analysis showed that soils were clustered by soil textures except a few soil series. This study applied only one property that was a length of neighboring soil series to GIS and statistical analyses. These results were compared to existing soil groups that were classified by new-soil taxonomy, texture, soil type and drainage level. It showed that these analyses can provide soil characteristics by soil texture. Based on this study, there is a need to investigate further objectively and quantitatively in statistical analyses of soil series.

Soil Classification of Anthropogenic Soils in a Remodeled Area Using Soil Taxonomy and World Reference Base for Soil Resources

  • Lee, Seung-Been;Chun, Hyen-Chung;Cho, Hyun-Jun;Hyun, Byung-Keun;Song, Kwan-Cheol;Zhang, Yong-Seon;Sonn, Yeon-Kyu;Park, Chan-Won
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.6
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    • pp.536-541
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    • 2013
  • In Soil Taxonomy system, anthropogenic soils are still classified as Entisols since the International Classification Committee for Anthropogenic Soils is in the process of classifying anthropogenic soils as new orders. In reality, it is difficult to characterize anthropogenic soils because Soil Taxonomy (ST) system does not distinguish between natural and anthropogenic Entisols. On the other hand, World Reference Base for soil resources (WRB) considers human impacts on soils and contains an independent category of anthropogenic soils, which makes easier to understand anthropogenic soil characteristics than Soil Taxonomy system. A remodeled paddy field (Gasan) was selected to classify by ST and WRB. Soil samples were taken to analyze chemical and physical properties. Based on the results of the analyses, the ST system classified Gasan as coarse loamy, mixed, mesic, Aquic Udorthents while the WRB did as Stagnic Urbic Technosols (Oxyaquic, Arenic). As a conclusion, the WRB classification information of the anthropogenic provides more detail characteristics of the anthropogenic soils.

Experimental Research on Impulse Breakdown Characteristics of Soil

  • Lee, Jaebok;Sughun Chang;Sungho Myung;Yuengue Cho
    • KIEE International Transactions on Electrophysics and Applications
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    • v.4C no.2
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    • pp.60-63
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    • 2004
  • The electrical breakdown characteristics of different types of soil samples have been measured. It is shown that the threshold soil breakdown strength is affected by many factors, such as types of soil, grain size, and soil compaction. The breakdown process in the test soil samples appears to be due to air ionization in the voids between the soil particles. The results have been compared with the relevant experimental results of other researchers.

Seismic Response Analysis Method of Bridge Considering Foundation-Soil Interaction and Multi-support Input Motion (기초-지반 상호작용을 고려한 교량의 다지점 입력 지진해석 기법)

  • Kim, Hyo-Gun;Choi, Kwang-Kyu;Eom, Young-Ho;Kwon, Young-Rog
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.284-291
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    • 2006
  • This paper presents a seismic response analysis of bridge structures considering foundation-soil interaction and multi-support input motion. In the earthquake analysis of structures it is usually assumed that the input ground motion is the same at all supports. However, this assumption is not justified for long structures like bridges, because observations have shown the earthquake ground motion can vary considerably within relatively small distances. When the soil under the foundation is relatively soft and deep, analysis for foundation-soil interaction always must be peformed. To consider foundation-soil interaction, soil response analysis is preceded, and after determining the material characteristics of foundation element obtained by foundation-soil interaction analysis at the frequency domain, the seismic response analysis of bridge superstructure with the equivalent spring and damper is performed. Finally, influences of multi-support input motion, which are affected by different soil characteristics, are also considered in this paper.

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Effect of Salinity on Mechanical Characteristics of Stabilized Dredged Soil (고화준설토의 역학적 특성에 대한 염분의 영향)

  • Kim, Yun-Tae
    • Journal of the Korean Geotechnical Society
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    • v.27 no.9
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    • pp.47-53
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    • 2011
  • Marine dredged soils taken from navigation channels or construction sites of coastal area usually have a lot of salt in pores of clayey soils. This paper investigates effect of salt on mechanical characteristics of non-salt and salt-rich stabilized dredged soil. The stabilized dredged soil (SDS) consisted of dredged soil and cement. Several pairs of SDS with non-salt and salt-rich dredged soils, noted as N-SDS and S-SDS, respectively, were prepared to compare their strengths and compressibility characteristics. The microstructures, strength and compressibility characteristics of N-SDS and S-SDS specimens at 7 and 28 days of curing time were evaluated using scanning electronic microscope (SEM), unconfined compression test, and oedometer test. It was found that salt concentration of clayey soil affected not only the formation of soil structure but also the strength development of mixture. The compression index and swelling index of S-SDS were also greater than those of N-SDS, which indicated that the compressibility of mixture increased due to salt concentration. Salinity in clayey soil had a negative effect on the strength development and compressibility characteristics of stabilized dredged soils.