• Title/Summary/Keyword: Weathering characteristic

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The Estimation of the Extent of Weathering using Fractal Dimension through a Comparison with Chemical Characteristic (화학적 특성과의 비교 분석을 통한 프랙탈 차원을 이용한 풍화도 추정)

  • Noh, Soo-Kack;Son, Young-Hwan;Bong, Tae-Ho;Park, Jae-Sung
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.2
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    • pp.127-135
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    • 2012
  • The processes of chemical and physical weathering occur simultaneously. The objective of this study was to estimate the degree weathered using fractal dimension through comparison with chemical characteristic of soil samples from Pohang (PH) and Kimpo (KP). Comparing chemical characteristics with fractal dimension, $SiO_2$, $Na_2O$, $K_2O$ content decreased and loss of ignition increased as fractal dimension increased. And fractal dimension showed high correlation with CWI while ATI, STI CIW, PI, CIA and RR demonstrated different degrees of correlation with fractal dimension. The tendency of the changes in oxide content and chemical weathering index with increasing fractal dimension appeared to be similar with the chemical changes due to weathering. Therefore, fractal dimension could be a good indicator representing the extent of weathering and chemical changes.

(A Study on Strength Anisotropy characteristic and Suggested Methods for Determining RQD as for Shale) (셰일의 강도이방성 특성 및 RQD결정에 관한 연구)

  • 이종규;이수곤;장서만;손경철
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.103-110
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    • 2003
  • This study is as for shale that attract recently geotechnical engineer more and more. like sedimentary rocks and metamorpic rocks, shales have many problem with anisotropy for stength and deformation and they have many problems with quick weathering progress and differential weathering of alternate bedding. In foreign countries, many renowned schalors, like Jaeger(1960),McLamore,Gray(1967),Donath(1972),Nova(1980),Hoek&Brown(1980),Ranamurthy(1985), have already studied for a variety of characteristic and announced high level results of their studies. In domestic also, there are many scholars who have announced high level research papers for shale. this study is a part of these stream. and this study not only analyzed strength anisotropy characteristic along with direction of testing(two-direction) by using point-load test(log-log method) but also compared uniaxial strength between the maximum saturated and dried condition. In this study, we also conducted slaking test. these results of slaking test show weathering characteristic of shales. also, we made the most of field data that obtained during slope stability project and we noticed that RQD measured in the field is much differ from drilled core RQD. In order to come close two different value or access to reality, we suggest new RQD method that artificially reduce RQD by separating core with light hand force.

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A Study on the Strength Degradation of Weathered Granite Soil by Freezing and Thawing (동결융해에 의한 화강풍화토의 강도저하에 관한 연구)

  • Kim, Yong-Soo;Jung, Soo-Jung
    • Journal of the Korean Geosynthetics Society
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    • v.6 no.3
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    • pp.1-7
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    • 2007
  • The property of weathered soil cannot but have a possibility of having a limit when its precise approaching due to the various weathering environment, and the peculiarity of its conduct affected by the weathering degree and effect factors. Especially most domestic or international researches are concentrated on the sedimentary soil, trying to analyze the mechanical behavior of weathered soil from the viewpoint of sedimentary soil. Therefore, it's difficult to judge if those results meet the actual conduct of weathered soil. This study suggested a way of weathering degree changing experiment as an early stage in an experiment of artificially changing weathering degree. In order to find out the property of strength change by the change of weathering degree, indoor mechanical experiment was made using soil sample after freezing and thawing. Under the weathering degree, characteristic change is watched by country rock and region of weathered granite soil.

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Physical and Chemical Variation of Sedimentary Rocks due to Weathering (풍화에 의한 퇴적암의 물리-화학적 변화)

  • Kim, Young-Su;Heo, No-Young;Jeong, Woo-Seob;Rui, Da-Hu;Lee, Jea-Ho
    • Journal of the Korean GEO-environmental Society
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    • v.3 no.2
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    • pp.49-60
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    • 2002
  • A study on mineral composition and chemical component governing of weathering process is necessary to know the weathering characteristics of sedimentary rocks. In this study, a mineral and chemical component analysis, and physical and engineering characteristic tests were conducted to find out the characteristics of sedimentary rocks in Daegu, according to the weathering degree of sedimentary rock. Test results show that the mineral composition of rock, such as Albite (Ab), Muscovite (Ms), Magenetite (Mt) and the chemical composition of $A_2O_3$, CaO, $Na_2O$, $K_2O$, MgO and so on are closely related to the weathering. Based on the test results, we illustrated the quantitative application of weathering decision for the sedimentary rocks.

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A Study of Weathering Characteristic of Baeknokdam Trachyte in Jeju Island (제주도 한라산조면암의 풍화특성에 관한 연구)

  • Lee, Chang-Sup;Cho, Tae-Chin;Lee, Sang-Bae;Won, Kyung-Sik
    • The Journal of Engineering Geology
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    • v.17 no.2 s.52
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    • pp.235-251
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    • 2007
  • Baeknokdam rock mass at the crest of Halla mountain is composed of Baeknokdam trachybasalt in the eastern region and Hallasan trachyte in the western region. On-going weathering, rockfall and collapse of Baeknokdam wall rock are closely linked to the weathering of trachyte distributed in the western region of Baeknokdam, though within the restricted area of eastern region trachybasalt blocks has been naturally formed and may be rolled down neering properties have been conducted. Based on the results of these experiments variations of mineralogical-petrographical characteristics of trachyte together with chemical and physical properties with respect to the degree of weathering have been analyzed. Weathering mechanism of Baeknokdam trachyte has been delineated by investigating the environmental cause of weathering and the peculiar features of weathered rock mass.

Characteristic Nature of the Unconformity between Holocene and Late Pleistocene in the Tidal Deposits along the Western Coast of Korea

  • Park, Yong-Ahn
    • The Korean Journal of Quaternary Research
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    • v.17 no.2
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    • pp.13-14
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    • 2003
  • It is generally well known that Quaternary is characteristic geologically in terms of glacial and interglacial repeats and their associated unconformity formation. This paper deals with the first finding of the characteristic and significant meaningful unconformity between Holocene and late Pleistocene, which implies submergence and emergence of the tidal sedimentary basin along the western coastal zone of Korea during interglacial stage(IOS-5e) and glacial time(IOS-2). The stratigraphy of intertidal deposits in the Haenam Bay, western coast of Korea shows two depositional sequence units (Unit I of Holocene and Unit II of late Pleistocene) bounded by an erosional surface of disconformity. The disconformity is related to the latest Pleistocene sea-level lowstands (probably during the LGM). The Unit II is interpreted as intertidal deposit showing tidal sedimentary structures and crab burrow ichnology and has two parts (the upper part and the lower part) showing different lithology and character. The upper part of Unit II shows characteristic subaerial exposure features (emergence) and its related lithology. Such subaerially exposed upper part (more or less 4m to 5m in thickness) is characterized by yellow-brownish sediment color, cryoturbat-ed structure, crab burrow ichnofacies and high value of shear strength. Geochemical and clay mineral analyses of the upper part sediments also indicate subaerial exposure and weathering. In particular, very high value of magnetic susceptibility of the upper part in comparison to that of the lower part is interpreted as pedogenetic weathering during the subaerial exposure period.

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Influence of Water on Compression Characteristic of Decomposed Granite Soil Based on Single Particle Crushing Strength (단입자파쇄강도에 기초한 화강풍화토의 압축특성에 미치는 수분의 영향)

  • Ham, Tae-Gew;Kim, Uk-Gie
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.101-109
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    • 2008
  • In order to investigate the influence of the water on compression characteristic of decomposed granite soils, a single particle crushing test and one-dimensional compression tests were carried out on three decomposed granite soils and Silica sand. The initial fracture strength for single particle reduced and variability of the strength increases due to weakening by existing water. Moreover, it was recognized that one-dimensional compression characteristic was related to the initial fracture strength characteristic, and the initial fracture strength also has the effect of weathering.

A Study on the Characteristic and Reinforcement of Road Cut Slope all over the HanGye Pass (한계령 일대 도로절토사면 특성과 보강방안 연구)

  • Rhee, Jong-Hyun;Kim, Seung-Hyun;Lee, Jung-Yup;Koo, Ho-Bon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.676-680
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    • 2006
  • Many collapse of road cut slope consisted of representative granite of korea peninsula is happened by weathering progress. Chose hangye pass consisted of korea peninsula's representative granite style for this study. Purpose of this study is that consider suitable reinforcement of cut slope consisted of granite by analyzing characteristic of hangye pass vicinity road cut slope.

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