• Title/Summary/Keyword: Weathering Degree

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Shear Characteristics of Weathered Granite Soils for Degree of Weathering and Saturation (화강토의 풍화도와 포화도에 따른 전단특성)

  • Song, Chang-Seob;Jang, Wong-Hee
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.3 no.3
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    • pp.1-7
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    • 2000
  • The aim of the work described in this paper is to study the shear characteristics of the weathered granite soil. To this end, a series of consolidated undrained triaxial compression tests are carried out to investigate the shear parameters-cohesion and internal friction angle for the degree of saturation and degree of weathering. From the results, it is found that the shear parameters of weathered granite soil are influenced on the degree of saturation, degree of weathering and disturbance. Especially, internal friction angle is more influenced on the upper factors than cohesion. And shear parameters are more acted on the degree of saturation than the degree of weathering in the test range. It is, therefore, recommended that must be considered the conditions of granite soil-degree of saturation, degree of weathering and disturbance etc-in case of the calculation of bearing capacity, stability analysis and other designs with shear parameters.

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Mechanical Characteristics of Weathered Granite Soils for Degree of Weathering and Saturation (풍화도과 포화도에 따른 화강토의 역학적 특성)

  • Lim, Seongyoon;Song, Changseob;Kim, Myeonghwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.57 no.3
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    • pp.93-100
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    • 2015
  • The object of this paper is to study the shear characteristics of the weathered granite soil. To this end, a series of consolidated undrained triaxial compression tests are carried out to investigate the shear parameters-cohesion and internal friction angle-for the degree of saturation and degree of weathering. From the results, it is found that the shear parameters of weathered granite soil are influenced on the degree of saturation, degree of weathering and disturbance. Especially, internal friction angle is more influenced on the upper factors than cohesion. And shear parameters are more acted on the degree of saturation than the degree of weathering in the test range. It is, therefore, recommended that must be considered the conditions of granite soil-degree of saturation, degree of weathering and disturbance etc-in case of the calculation of bearing capacity, stability analysis and other designs with shear parameters.

Experimental approach to evaluate weathering condition of granite using electrical resistivity

  • Oh, Tae-Min;Cho, Gye-Chun;Son, Thai An;Ryu, Hee-Hwan;Lee, Changho
    • Geomechanics and Engineering
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    • v.8 no.5
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    • pp.675-685
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    • 2015
  • Weathering is the breaking/cutting down process of rocks due to physical and chemical processes in natural as well as artificial environment including $CO_2$ injection for storage in the sediment, or natural resource recovery process. This study suggests an alternative method to estimate the degree of weathering for granites. A series of laboratory and field experiments are performed to measure electrical resistivities on various rock samples experienced different degrees of weathering and their residual soils under different saturation conditions. It is found that the normalized electrical resistivity increases with a decrease in water absorption and the saturation. Simple boundaries are suggested to identify the weathering degree of granites, based on limited data. Field test results for three sites confirm that the suggested method could be estimated well the degree of weathering of granites compared with the other methods suggested previously. Although further research is required, this study suggests that an electrical resistivity could be an effective approach to estimate the degree of weathering of granites compared with the other methods suggested previously.

Estimation of Weathered Degree Using Fall cone in Weathered Soil ; Silty Sand (Fall Cone을 이용한 풍화도 측정(실트질 모래에 대하여))

  • Son, Young-Hwan;Kim, Seong-Pil;Chang, Pyoung-Wuck
    • Journal of The Korean Society of Agricultural Engineers
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    • v.50 no.1
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    • pp.61-68
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    • 2008
  • It is essential to analyze and classify the physical characteristics of weathered granite for engineering purposes. This paper is to suggest a physical method to determine the degree of weathering of weathered soils. A new classification method for determining the degree of weathering is suggested, based upon the results from laboratory tests including fall cone test. According to the proposed physical method using fall cone apparatus, the measured values of the samples from the same area show distinctive difference of weathering. The water content tends to increase with increasing the degree of weathering at the same penetration in fall cone test. And relationship between CWI and water content are expressed one equation in Hwaseong area and Ilsan area.

Estimation of Degree of Weathering in Residual Soil Using Water Content from Fall Cone Test Result (Fall cone test의 함수비를 이용한 잔적토의 풍화도 측정)

  • Son, Young-Hwan;Chang, Pyoung-Wuck;Kim, Seong-Pil
    • Journal of the Korean Geotechnical Society
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    • v.23 no.12
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    • pp.13-23
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    • 2007
  • Weathered soils appear from the rock and its weathering result. In accordance with the degree of weathering the roch may become soft rock, weathered rock and residual soil. In general, classification method for determining the degree of weathering are performed by chemical method and N-value. But these method have some problems. So, this research is to suggest an appropriate physical method to determine the degree of weathering of weathered soils. A new classification method for determining the degree of weathering is suggested, based upon the results from fall cone test. According to the proposed physical method using fall cone apparatus, the measured values of the samples from the same area show distinctive difference of weathering. For the checking, we selected two areas. As a result, the relationship between CWI and water content according to penetration is expressed as an equation in Ilsan and Incheon area. And it proved to be a good method to determine the degree of weathering.

Evaluation Methods of Weathering Degree for Korean Decomposed Granite Soils (국내 화강풍화토 지반의 풍화도 평가방법)

  • 박병기;이광찬
    • Journal of the Korean Geotechnical Society
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    • v.15 no.1
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    • pp.127-140
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    • 1999
  • In this study, decomposed granite soil samples were taken from 16 different regions and their weathering properties were investigated by testing their physical and chemical properties. According to the results, the Chemical Weathering Index (CWI) ranges from 15.5 to 30 in general and 12 out of the 16 regions show over 20 in CWI. The 12 regions are categorized into complete granite soil areas by Sueoka's classification. CWI, Li. $SiO_2,\; \DeltaS/S$ and SAR are all correlated significantly and used as indicators by which the degree of weathering can be judged. The degree of weathering can be measured especially through Li or $SiO_2$ which is considered as an easy approach of geotechnical classification. Also, the relationship between the value of N and Li is regarded as a good indicator in estimating the degree of weathering.

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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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Analysis The Intensity of Weathering of The Rock Surface Using 3D Terrestrial Laser Scanner and Thermal Infrared Instrument (열적외선 기기와 3차원 레이저 스캐너를 이용한 암석 표면의 풍화강도 분석)

  • Lee, Soo-Gon;Cho, Hang-Kyo;Xu, Jing
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1324-1333
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    • 2010
  • This paper is used in a recent civil engineering field in three-dimensional laser-meter tiles using thermal imaging cameras for the weathered rock slopes precisely measured indirectly, to the degree that began in the will. In the field is difficult to access the degree of weathering of the rock slope to the existing direct way to compensate for the shortcomings of 3D Terrestrial Laser Scanner and weathering characteristics of rocks using thermal imaging cameras to get the information to analyze the degree of rock weathering is. Intensity of 3D TLS and the thermal camera with image analysis to analyze the degree of weathering of bedrock in the field of core drilling targeting indoor laboratory tests were analyzed through the study. Granite, gneiss, sandstone, much of the cancerous samples, each experiment has a 40 per category, each of which 30 were used to analyze the data collected. That degree of rock weathering, the rock, depending on the strength of the Intensity values can change, depending on the level of thermal imaging camera, also weathered the changes in temperature could see. Intensity is the strength of weak rocks, the more value decrease, the temperature of the thermal imaging camera through the swell Intensity and notice that the temperature had an inverse relationship. Intensity value of the low strength of weak rock, but the value came out of the rocks have been proved to be largely dependent on the contrast. The contrast of the surface rocks are weathered dark Intensity values lower temperature to swell the contrary, the degree of weathering can be distinguished.

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A Quantitative Study on the Variational Features of Rock Properties Followed by Weathering in Granites (풍화현상에 수반되는 화강암의 물성변화에 관한 연구)

  • Kim, Yeonghwa;Hong, Soon Ho
    • Economic and Environmental Geology
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    • v.23 no.2
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    • pp.221-232
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    • 1990
  • Upon the basis of the measurements of index properties and ultrasonic velocities as well as the determination of degree of weathering mainly based on microscopic observation, relatively fare correlation has been found between the degrees of weathering and the physical properties of rocks, particularly between degrees of weathering and maximun water content. A significantly better correlation has been obtained between degree of weathering and P wave velocity by grouping rock samples according to rock facies. This study presented the range of physical parameters corresponding to each degree of weathering in granites.

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A Study of Engineering Properties and Deformation Behavior of Weathered Rock Mass (풍화 암반의 공학적 특성 및 변형거동에 관한 연구)

  • 강추원;박현식;김수로
    • Explosives and Blasting
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    • v.22 no.2
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    • pp.33-43
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    • 2004
  • The six grades weathering system is normally used in weathered rock classification. In this study. fresh and weathered rock block of grade I to V were sampled in Jang-soo ana but samples of the grade VI was omitted from this study. The variation quantities of chemical weathering indices with weathering degree are smaller than those of physical and mechanical properties. Increase of Weathering degree is well indicated by physical and mechanical properties such as strength, hardness, ultrasonic velocity and slake durability result. Especially, absorption and porosity ratio is a good indicator. As weathering proceeds. a number of the cracks affect the rock deformation. Therefore, stress-strain curves of weathered rocks in unconfined state are quite different from ones of fresh rocks.