• 한국농공학회논문집
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• 제54권2호
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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.

• 한국지형학회지
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• 제23권1호
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• pp.1-16
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• 2016

This study estimates relationships between physical and chemical weathering indices of various rock types and topographical relief. Physical weathering properties such as rock strength and joint and chemical weathering indices such as the $SiO_2/Al2O_3$, CIA and WPI were analyzed from 18 rock outcrops in mountain and valley areas consisting of 9 rock types. The results indicate that the elevation and relief of topography increase physical strength of rock increases. It can be suggested that the total r(rock-mass strength rating) and R(rock rebound strength by Schmidt Hammer) are most useful indices as a quantitative weathering property factor to explain formative causes of topographical relief. The results also suggest that rock types such as sandstone, granite, gneiss and schist are most suitable to explain meaningful difference in topographical relief with the physical and chemical weathering indices.

• 지질공학
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• 제27권4호
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• pp.451-462
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• 2017

Physical weathering caused by external forces and chemical weathering caused by the decomposition or alteration of constituent materials are the two factors that dominate the mechanical properties of rocks. In this study, a field investigation was undertaken to identify the physical and chemical weathering characteristics of the biotite granite and granitic weathered soils in Gyeongju, South Korea. Samples were collected according to their grade of weathering and subjected to modal analysis, XRD analysis, XRF analysis, physical property tests, particle size distribution tests, and slake durability tests. Modal and XRD analysis identified these rocks as biotite granite; secondary alteration minerals were not observed. Physical property tests and particle size distribution analyses indicate an average porosity of 41.28% and a sand content of > 90 wt.%. These values are somewhat higher than those of granites in general. The results of the slake durability test and XRF analyses show that the physical and chemical weathering indices of the samples vary with the degree of weathering.

• 자원환경지질
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• 제8권4호
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• pp.211-221
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• 1975

Weathering of granites has a geochemical role of great significance, because of their abundance and because of chemical instability near the surface of the earth, which is more pronounced than in most other rocks. On the other hand the granites are tectonically fragile and "react" to deformation with marked facility, giving rise to a whole gamut of deformed rocks. Therefore, the writer has studied on the weathering of granitic rocks at of Iri city and Jeonju city Jeollabukdo, Korea, The fresh and weathered rocks were used as material for the investigation. The results obtained by chemical analysis and observation are as follows. 1) The order of mobility in major elements was Ca, Na and K$H_2O$ was observed clearly and late stages of weathering processes. 3) The early stage of weathering is commenced by physical weathering and followed by chemical weathering. 4) The ratio of FeO/. $Fe_2O_3$, FeO/MgO, and $SiO_2/Al_2O_3 $ decreased uniformly from early to late stage of weathering processes. 5) It was proved that weathering potential of granite was larger than that of basaltic rocks.

• 자원환경지질
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• 제7권4호
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• pp.175-184
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• 1974

Weathering of granites has a great geochemical significance, because of their chemical stability near the earth surface which is more pronounced than in most other rocks. The author intended to observe the relative mobility of major elements in weathering process of the granite, distributed on outskirts of Iri city Jeolla-bugdo, Korea. He analysed fresh granites and weathered ones from the Baeg-Gu granite mass and obtained following conclusions in the triangle-diagrams and the oxidized variation diagrams of the samples. 1) The increasing phenomena of $H_2O$ was observed clearly in early and late stages of weathering process. 2) The early stage of weathering is commenced by physical weathering and followed by chemical weathering. 3) The ratio of $FeO/Fe_2O_3$, FeO/MgO, and $SiO_2/Al_2O_3$ decreased uniformly from early to late stage of weathering processes. 4) It was proved that weathering potential of granite was larger than that of basaltic rock. 5) The order of mobility in major elements was Ca, Na and K

• 한국토양비료학회지
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• 제47권3호
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• pp.179-186
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• 2014

Weathering indexes of the typical pedons derived from different parent materials of the soils of Korea were calculated by Kronberg and Nesbitt (1981) to understand weathering degree of the soils which might give a clue of soil formation and characterizing a soil pedon. The weathering index W1 was chemical change index, and the weathering index W2 was silicate dominant index. The chemical compositions of the 49 typic pedons were extracted from the Taxonomical Classification of Korean Soils (NIAST, 1999). The weathering indexes of Kimhae series, derived from fluvio marine material, were the highest among the analyzed soils. Within parent materials, the weathering indexes of the soils derived from limestones parent materials were high, and those derived from phorphyry materials were low. The relationship between W1 and W2 showed unique pattern which implied certain sequence within the same parent materials.

• 터널과지하공간
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• 제22권1호
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• pp.32-42
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• 2012

암석에 대한 풍화특성 연구는 시공간적 제약으로 인한 어려움이 따른다. 이 연구는 경상남도 김해시 일대에 분포하는 백악기 화강암에 대하여 물리적 및 화학적 풍화과정을 인공적으로 재현하고 풍화진행에 따른 암석의 지질공학적 특성변화를 고찰하였다. 인공풍화과정에 의하여 시료의 탄성파속도는 현저하게 감소하였으며 공극률 및 흡수율은 뚜렷하게 증가하였다. 초기 풍화등급이 높은 암석일수록 인공풍화과정에 따른 물성변화의 폭이 크며 풍화에 취약한 것으로 나타났다. 공극률, 흡수율 및 탄성파속도는 연구지역의 화강암에 대한 풍화지수로 유용하게 사용할 수 있다. 물리적 및 화학적 풍화과정이 복합적으로 일어나는 조건에서 암석풍화는 더욱 촉진된다. 이 연구에서 복합적인 풍화과정을 재현한 연구방법은 암석의 풍화특성을 규명하고 예측하는 데에 활용할 수 있을 것으로 기대된다.

• 한국지반공학회논문집
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• 제15권1호
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• pp.127-140
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• 1999

본 연구는 16개 지역 화강풍화토를 대상으로 물성시험과 화학시험을 실시하여 화강토의 풍화특성을 파악하였다. 그 결과, 화학적 풍화지수(CWI)가 15.5~30의 범위내에 있고 CWI가 20이상인 화강토가 12개 지역이 해당되며 Sueoka의 분류법에 의하면 완전풍화토로 분류되었다. 특히 화학적 풍화지수(CWI)와 강열감량(Li), $SiO_2,\; 파쇄비(\DeltaS/S)$, SAR간의 관계가 좋은 대응을 보여 이들 모두 풍화정도를 판단하는 지표가 될 수 있으며 이 가운데 특히 Li나 $SiO_2$에 의한 풍화도의 판정은 지반 공학적으로도 쉽게 접근할 수 있는 분류법으로 생각되었다. 그리고 N치와 Li의 관계도 풍화의 정도를 판단하는 좋은 지표가 될 수 있다고 본다.

• 한국지반환경공학회 논문집
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• 제3권2호
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• pp.49-60
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• 2002

퇴적암의 풍화특성을 파악하기 위해서는 풍화과정을 지배하는 암석의 광물조성과 화학성분에 대한 연구가 필요하다. 본 논문에서는 풍화정도에 따른 퇴적암의 특성을 고찰하기 위해서 대구지역에 분포하고 있는 퇴적암을 채취하여 화학 및 광물성분 분석과 물리 및 역학특성 시험을 실시하였다. 화학적풍화지수와 감열감량, 흡수율과 일축압축강도, 풍화지수와 일축압축강도가 좋은 상관관계를 나타내었으며 모암에 함유된 $A_2O_3$, CaO, $Na_2O$, $K_2O$, MgO 등의 화학성분과 조장석(Albite, Ab), 백운모(Muscovite, Ms), 마그네타이트(Magenetite, Mt)등의 광물성분이 풍화와 밀접한 관계가 있었다. 이 시험결과를 토대로 하여 퇴적암에 적용할 수 있는 정량적인 풍화도판정법의 적용성을 제시하자고 하였다.

• 자원환경지질
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• 제26권1호
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• pp.67-81
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• 1993

This dissertation is a basic research on the degradation of rocks and aims at clarifying the relations between the progression of degree of weathering and the variation of chemical composition. The author wants to make clear the degradation of rocks and the process of formation of sedimentary rocks from a standpoint of elucidation of migration of elements. This study is considered to be significant not only as a part of research on the distribution of earth crust materials but as the petrogenesis of rocks. The chemical studies on the weathered rocks have been started relatively early and there are not a few researches on them: Goldich, 1938; Harris, et al., 1966; Ruxton, 1968; Berner, et al., 1982; Kanuss, 1983; Lasaga, 1984; Siagel, 1984. The degree of migration of elements in weathering is the composite result of various factors. Because, at the present time, it is difficult to clarify the individual and composite effects of each factor theoretically and quanititatively, we must accumulate empirical data and use them relatively. In such consideration the author acquired some data of chemical weathering from the chemical analysis of granitic and basaltic rocks in and around Fukuoka city, Japan and granitic rocks in and around Chonju and Iri cities, Korea. Because both rock types studied can be considered as representative materials of acidic and basic rocks compsing the earth crust, it is significant to examine the phenomena of weathering of both rock types. The following results are obtained from the analysis and examinations of chemical compositions of the original and weathered rocks. The loss rate of major elements has no uniformity, but the following relation holds in general; Ca, Na> K, Si> Mg> Fe, Al. As weathering proceeds, the ratio of $Al_2O_3/CaO$ shows increasing phenomena, and that of $Na_2O/CaO$ decreasing. The range of migration of composition is broad in basaltic rocks but narrow in granitic rocks. The reason is that the chemical weathering of basaltic rocks progresses more easily than that of granitic rocks. The chemical weathering potenitial index of basaltic rocks in larger than that of granitic rocks. The reason is that the chemical weathering of basaltic rocks proceeds more easily than that of granitic rocks. In weathering, the decrease of mobile cations such as $Ca^{2+}$, $Na^{2+}$, $Mg^{2+}$ and the increase of $H_2O$ in basaltic rocks are more obvious than in granitic rocks.