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  • Title/Summary/Keyword: SOIL CHARACTERISTICS

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The Compressive Strength and Durability Characteristics of Lime-Cement-Soil Mixtures (석회-시멘트 혼합토의 압축강도 및 내구 특성)

  • Oh, Sang-Eun;Yeon, Kyu-Seok;Kim, Ki-Sung;Kim, Yong-Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.1
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    • pp.83-91
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    • 2012
  • In this study, the compressive strength characteristics of lime-cement-soil mixtures, composed of lime, soil, and a small amount of cement, were investigated by performing the unconfined compression tests, the freezing and thawing tests, the wetting and drying tests and the permeability tests. The specimens were made by mixing soils with cement and lime. The cement contents were 0, 6, 8 and 10 %, and the lime contents were 2, 4, 5, 10, 15 and 20 % in weight. Each specimen was cured at constant temperature in a humidity room for 3, 7 and 28 days. The compressive strength characteristics of the lime-cement-soil mixtures were then investigated using the unconfined compression tests, freezing and thawing tests and the wetting and drying tests. Based on the test results, a discussion was made on the applicability of the lime-cement-soil mixtures as a construction material.

A Study on the Infiltration Characteristics of Soil Cut-Slope (토사절토사면의 침투특성에 관한 연구)

  • Lee, Jeong-Yeob;Koo, Ho-Bon;Kim, Seung-Hyun;Bae, Gyu-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.735-738
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    • 2005
  • The purpose of this study is the infiltration characteristics of soil cut-slope by rainfall. Stability analysis of soil cut-slopes has been conducted by limit equilibrium method on Seep/w and finite element method on Slope/w. Result is same as following. First. the hour when seepage line and groundwater in contact is proportionate from rainfall rate condition and upper natural slope gradient condition which is identical. Second, when seepage line and groundwater is contact, seepage line moves gradually at soil cut-slope surface. Finally, seepage line is formed similarly with soil cut-slope gradient. Third, when rainfall is ended, from the recording upper natural slope where the hour will pass it is stabilized

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Characteristics of Youngjong Deposits with Engineering and Geological Standpoints (공학적/지질학적 관점에서 본 영종도 퇴적지반의 특성)

  • Kim, Ju-Hyong;Choi, Kyung-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.755-760
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    • 2009
  • It is essential to carry out site investigations such as SPT, CPT sampling etc. to understand the characteristics of soil deposits. However, the results deduced only from the engineering standpoint have limited information to fully understand ground characteristics. In this study, it is discussed site investigation results on Youngjong deposits obtained from not only the geotechnical standpoint, but also geotechnical and geological mixed standpoint to understand correct characteristics of Youngjong soil deposit.

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Physical and Chemical Characteristics of Dokdo Soil

  • Lee, Gil-Seong;Choo, Yeon-Sik
    • Journal of Ecology and Environment
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    • v.32 no.4
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    • pp.295-304
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    • 2009
  • To understand the properties of soil in Dokdo, we collected soil samples from 12 locations on Seodo and 23 locations on Dongdo, in Dokdo of Gyeongsangbuk-do Province in 2007-2008 and analyzed the soil's physical and chemical characteristics. Sand comprises the largest component (49.37%) of Dokdo soil, followed by silt (40.70%) and clay (9.93%). The soil structure consists mostly of sand loam, followed by loam and silt loam. The pH level of soils from Dokdo varied dramatically among sampling sites and seasons, ranging from 3.36 to 8.02. The total ion content of Dokdo soil also varies greatly among survey places and periods, but in general the total ion content was high in summer when vegetation develops, and low in spring. The exchangeable cation contents of the soil showed low levels in samples where the soil pH was low, including habitats dominated by Agropyron tsukushiense var. transiens and Echinochloa crus-galli, whereas the exchangeable cation contents were high where the organic contents were high, as in habitats dominated by Liriope platyphylla and Artemisia japonica subsp. littoricola. Soil N contents varied greatly among survey sites and higher N contents were found in soil inhabited by Chenopodiaceous plants than in habitats inhabited by other plants. The substantial differences in phosphorus contents among sites were related to excrement of black-tailed gulls. To understand the basic physical and chemical features of the soil on Dokdo, it will be necessary to conduct seasonal and long-term research on soil pH, ion contents, organic contents, N and P, as well as obtaining precise data from samples collected at different depths.

Physiological Characteristics and Seedling Growth Patterns of Neem (Azadirachta indica A. Juss) under Different Soil Conditions

  • Ghimeray, Amal Kumar;Wu, Jin-Cheng;Sharma, Pankaja;Park, Chol-Ho;Cho, Dong-Ha
    • Korean Journal of Plant Resources
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    • v.22 no.6
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    • pp.528-534
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    • 2009
  • The study of germination and seedling growth characteristics of Neem under different soil and environment conditions was undertaken. The seed germination started 8 days after sowing in commercial bed soil, whereas, delayed germination was observed in sandy-loam (15 days) and sandy (19 days) soil. The highest germination (73.33%) was observed in commercial bed soil in green house, whereas, the lowest germination was observed in sandy soil (16.67%) and sandy-loam soil (8.33%). The seeds in the open field (sandy soil) also showed poor (10%) germination. The mean number of germination seed/day (GD) and seed germination vigor rate (GV) both were highest in the commercial bed soil with 0.733% and 16.67% respectively in the green house, whereas sandy and sandy-loam soil in green house and open field (sandy soil) all showed much lower GD and GV values. The seedling characteristics of nursery revealed that the seedling grown in the growth chamber in commercial bed soil was significantly higher in all the parameters comparing to others grown in green house and open field. The growth was nearly 7 fold in the chamber compared to that of the green house nursery observed in three months old seedlings. Likewise, HPLC analysis revealed that the green house grown seedling contain higher quantity of pigments compare to the chamber grown seedlings. Among the soils used the commercial soil alone or in combination with sandy and sandy-loam soil in the ratio of 2:1:1 respectively with the temperature of 27±2C showed better for Neem nursery preparation.

A Study on the Absorption Characteristics of Soil Block and Soil Plaster as Eco-Friendly Building Materials (친환경 건축재료로서의 흙벽돌과 흙미장의 흡음 특성에 관한 연구)

  • Hwang, Seong Il;Chu, Mun Ki;Hwang, hey joo;Oh, yang ki
    • KIEAE Journal
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    • v.7 no.3
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    • pp.57-62
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    • 2007
  • Most of current building materials are made of organic compounds or at least made with chemical treatments. Though easy to use and comparatively pay less, those materials are generally not enviornmentally sound. VOC is one of harmful effects. On contrary, natural materials such as soil are usually eco-friendly, and environmentally sustainable as well if not treated in autoclaves. Acoustica materials made of such environmentally sound and sustainable could be widely used. It is aimed to prove that soil based materials could be effectively used in acoustical fields rather than the other usual materials. Experiments with various types of soil blocks and soil plaster were performed. It is proved that the soil plaster has better apsorption features than cement plaster. Soil blocks have higher absorption cofficients than soil plaster, due to the thickness, and the absorption characteristics can be controlled by the design of the blocks.

Characteristics of Anthropogenic Soil Formed from Paddy near the River

  • Sonn, Yeon-Kyu;Zhang, Yong-Seon;Hyun, Byung-Keun;Kim, Keun-Tae;Lee, Chang-Hoon
    • Korean Journal of Soil Science and Fertilizer
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    • v.49 no.5
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    • pp.434-439
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    • 2016
  • Anthropogenic soil in cropland is formed in the process of subsoil reversal and the refill of soil into cropland. However, there was little information on the chemical properties within soil profiles in anthropogenic soil under rice paddy near the river. In this study, we investigated the chemical properties within soil profiles in the anthropogenic soil located at 4 sites in Gumi, Kimhae, Chungju, and Euiseong to compare with the natural paddy soil near the river. Among particle sizes, the sand content decreased under soil profiles but the silt and clay contents increased compared to the natural paddy soil in soil profiles. Organic matter content in topsoil of anthropogenic soil was lower than in that of natural soil, which was shown the contrary tendency within soil profiles. Also, the soil pH, available P2O5, and exchangeable cations were higher in anthropogenic soil compared to natural paddy soil at topsoil, which was maintained these tendency into soil depth. Nutrients may be equally distributed in anthropogenic soil during the process of refill in paddy soil near the river. This results indicated that anthropogenic soil would contribute to carbon sequestration, the mitigation of compaction, and reduction of fertilizer application in paddy soil. Therefore, characteristics of anthropogenic soil can be used for the soil management in cropland.

The degradation characteristics of waste cigarette filter in outdoor (실외에서 발생되는 폐 담배필터의 분해특성)

  • 김주학;윤오섭;이문수
    • Journal of the Korean Society of Tobacco Science
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    • v.21 no.2
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    • pp.136-143
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    • 1999
  • This study was conducted to evaluate the degradation characteristics of waste cigarette filters under 0, 5, 10, and 15cm in depth from soil surface by environmental conditions. Weather was the most important factor during degradation of waste cigarette filters in this study. Bulking of cellulose acetate filaments exposed on soil surface was observed after 2 months, but the form of filter was kept up after 12 months. The treated cigarette filters in soil landfill revealed a little different degradation pattern at each soil landfill depth, The sample in 5cm depth of soil was more degraded then other site. A fluffy appearance of cellulose acetate filaments in the control filter rods was also developed more strongly in soil landfill then on soil surface. From the observation of waste cigarette filters by scanning electron microscopy, much degradation of the fiber of waste cigarette filters could be ascertained in soil landfill. The weight of waste cigarette filters under 5cm from soil surface was reduced about 50%, and the tensile strength of the samples in soil surface and under 5cm from soil surface were reduced 66.0% and 92.4%, respectively. The microbial experiment date that the viable cell number in microbial population and cellulolytic microorganisms showed the maximum values under 5cm from soil surface, suggest that microorganisms in soil play an important roll in the degradation of acetate cigarette filters.

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Analysis of Soil Moisture Recession Characteristics in Conifer Forest (침엽수 산림에서의 토양수분 감쇄특성 분석)

  • Hong, Eun-Mi;Choi, Jin-Yong;Nam, Won-Ho;Yoo, Seung-Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.53 no.4
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    • pp.1-9
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    • 2011
  • Forest area covers 64 % of the national land of Korea and the forest plays a pivotal role in the hydrological process such as flood, drought, runoff, infiltration, evapotranspiration, etc. In this study, soil moisture monitoring for conifer forest in experimental forest of Seoul National University has been conducted using FDR (Frequency Domain Reflection) for 6 different soil layers, 10, 20, 30, 60, 90 and 120 cm during 2009~2010, and precipitation data was collected from nearby AWS (Automatic Weather Station). Soil moisture monitoring data were used to estimate soil moisture recession constant (SMRC) for analyzing soil moisture recession characteristics. From the results, empirical soil moisture recession equations were estimated and validated to determine the feasibility of the result, and soil moisture contents of measured and calculated showed a similar tendency from April to November. Thus, the results can be applied for soil moisture estimation and provided the basic knowledge in forest soil moisture consumption. Nevertheless, this approach demonstrated applicability limitations during winter and early spring season due to freezing and melting of snow and ice causing peculiar change of soil moisture contents.

Cover Crop Effects of Winter Rye (Secale cereale L.) on Soil Characteristics and Conservation in Potato (Solanum tuberosum L.) Slope Field (경사밭 감자(Solanum tuberosum L.) 재배 시 휴한기 호밀(Secale cereal L.) 재배에 따른 토양 특성 및 토양 보전 효과)

  • Bak, Gyeryeong;Lee, Jeong-Tae
    • Journal of Environmental Science International
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    • v.30 no.12
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    • pp.1015-1025
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    • 2021
  • Our research work aimed to evaluate cover crop effects of winter rye on soil characteristics, soil conservation, and yield productivities on potato fields with 15% slope during a fallowed period. There were two controls of bared field without any cultivation and conventional potato cultivation without winter rye. Potato cultivation increased soil pH, organic matter, available phosphate, and exchangeable cation regardless of cover crop cultivation. Sub-soil, particularly, all components of soil chemical properties showed higher value in winter rye cultivation than conventional cultivation. Higher soil density was observed on cover crop cultivation than conventional cultivation resulting from root residues of the cover crop both topsoil and subsoil. Cover crop residues positively affected plant growth and reduced the amount of soil erosion by holding the soil. Although severe soil erosion was seen in conventional cultivation, winter rye cultivation declined soil erosion by 47% during the fallow period on potato slope fields. Distinct soil bacterial communities were detected among treatments and some OTU(Operational Taxonomic Unit)s showed significantly higher abundance in winter rye treatment. Total yield and commercial rate demonstrated no significant differences while higher tuber phosphate, K+, and Mg2+ contents were observed in winter rye cultivation.