• Title/Summary/Keyword: 차별풍화

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Relationships Between Physical Properties and Topography in Mountain and Valley Bedrocks (산지와 곡지 암석의 물리적 특성과 지형 사이의 관계)

  • Park, Chung-Sun;Lee, Gwang-Ryul
    • Journal of The Geomorphological Association of Korea
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    • v.23 no.3
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    • pp.27-39
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    • 2016
  • This study statistically investigates relationships between physical properties of rocks and topography by measuring and analyzing section, topographical and measured parameters of 58 bedrock outcrops at areas covered by gneiss, schist, granite, andesite, sandstone and limestone in the Korean Peninsula. Multiple linear regression analysis suggests that the joint spacing, joint continuity, weathering grade and maximum joint width of rocks among the measured parameters are related to the topographical parameters with statistical significances. Therefore, this study suggests that rock properties such as joint spacing, joint continuity, weathering grade and maximum joint width seem to greatly influence topography, although various factors can affect topographical parameters.

Risk Assessment of Cut Slope by Gravity Field Interpretation and Modelling (비탈면 위험도 평가를 위한 중력장 해석 및 모델링)

  • Choi, Sungchan;Kim, Sung-Wook;Choi, Eun-Kyoung;Lee, Yeong-Jae;Jang, Hyun-Ick
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.533-540
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    • 2021
  • Gravity field analysis and density modeling were performed to evaluate the internal state of the rock mass, which is the cause of cut slope collapse. The shape of the weathered zone and the depth of basement could be confirmed from the complete Bouguer anomaly and density model. The basement depth at the center of the cut slope calculated using the Euler deconvolution inverse method is 30 m, which is about 10 m deeper than the surrounding area. In addition, the depth of basement and the thickness of the weathered zone are similar to the boundary between low resistivity and high resistivity in dipole-dipole survey. From the study results, gravity field analysis and density modeling recognizes the internal state of the rock slope and can be used for slope safety analysis, and is particularly suitable as a method to determine the shape of weathered zones in interpreting the safety of cut slopes

Topographical Landscapes and their Controlling Geological Factors in the Cheongryangsan Provincial Park: Lithologic Difference and Faults (청량산 도립공원의 지형경관과 지질학적 지배 요인: 암질차이와 단층)

  • Hwang, Sang Koo;Son, Young Woo;Son, Jin Dam
    • The Journal of the Petrological Society of Korea
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    • v.26 no.3
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    • pp.167-181
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    • 2017
  • Cheongryangsan area ($49.51km^2$) has been designated as the Provincial Park in 1982, because it has magnificent aspect and seasonally spectacular landscapes. Especially, Cheongryangsa sitey ($4.09km^2$) has been designated as Noted Scenery No. 23 in 2007, because it has the same topographical landscape as rock cliffs, rock peaks and caves. The most spectacular landscapes are exhibited in the Cheongryangsan Conglomerate and Osipbong Basalt. There are twelve rock peaks on the ridges of the two strata, and many rock cliffs in the several valleys of strata, in which a few caves are formed by differential weathering and erosion. The valleys, in which flow Cheongryang, Bukgok and Cheonae streams, are classified as fault valleys along WNW-ESE faults. The rock cliffs were generated from vertical joints parallel to WNW-ESE faults in the two strata, and the caves were formed by differential weathering and erosion along bedding of sandstones and shales intercalated in the conglomerates. The rock peaks are landscapes formed by differential erosion along crossed vertical joints in the ridges. The vertical joints are developed subparallel to two WNW-ESE faults and a NNE-WWS fault. Therefore the topographical features are caused by existence of the faults and Lithologic difference in the Cheongryangsan Conglomerate and Osipbong Basalt, and by differential weathering and erosion along them.

A Case Study on the Slope Reinforcement Methods of Differential Weathering (심한 차별풍화의 사면 보강 시공 사례)

  • Jung, Jin-Gyo;Kim, Moon-Gyu;Oh, Myung-Ju;Oh, Myung-Soo;Ahn, Ji-Eun;Ku, Jun-Gee;Bae, Seung-Hyeon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1344-1350
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    • 2008
  • The slope surface at a linking road construction from a geological stratum situation and a spot investigation weathering about the base rock. We became formation the slope to very disadvantageous base rock. A stability review result confirmed report of the slope were difficult and presented the stability countermeasure. We executed the slope to the purpose to augment safely.

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Types and Characteristics of Landslides in Danyang Geopark (단양 지질공원 내의 산사태 유형과 특징)

  • Seong-Woo Moon;Ho-Geun Kim;Yong-Seok Seo
    • The Journal of Engineering Geology
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    • v.33 no.3
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    • pp.427-438
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    • 2023
  • We carried out a geological survey to classify the types of mass movement in Danyang Geopark (where various rock types are distributed) and analyzed the mechanical and hydraulic characteristics of landslide materials using a series of laboratory tests. Debris flows occurred in areas of limestone/marble, shale, and porphyroblastic gneiss, and limestone/marble landslides were distinguished from the others through the presence of karren topography. Soil tests showed that soil derived from weathered gneiss, which has a higher proportion of coarse grains, has a higher friction angle, lower cohesion, and larger hydraulic conductivity than soils from areas of limestone/marble, and shale. Rock failure mass movements occurred in areas of phyllite, sandstone, and conglomerate and were subdivided into plane failure, block-fall, and boulder-fall types in areas of phyllite, sandstone, and conglomerate, respectively. The shear strength of phyllite is much lower than that of the other types of rock, which have similar rock quality. The slake durability index of the conglomerate is similar to that of the other rock types, which have similar degrees of weathering, but differential weathering of the matrix and clasts was clearly observed when comparing the samples before and after the test. This study can help establish appropriate reinforcement and disaster prevention measures, which depend on the type of mass movement expected given the geological characteristics of an area.

Geomorphological Environment of Suwon Basin (수원 분지의 지형 환경)

  • Kee, Keun-Doh;Lee, Sang-Whan
    • Journal of the Korean association of regional geographers
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    • v.10 no.2
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    • pp.300-312
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    • 2004
  • The geomorphological environment of Suwon Basin consists of two great elements: mountains which surround the basin and plains and low relief hills by differential erosion of granitic area. Nothern and eastern parts of the basin surround with gneissic mountains(Mt. Kwangkyo), southern and western parts of the basin with granitic mountains(Mt. Chilbo, etc). The basin developed on granitic saprolites is composed of two types of sub-order geomorphic elements: flood plains alongside four river(Whangkuji-chon, Seoho-chon, Suwon-chon, Wonchonri-chon) and aligned hills and mounts between the river side plains. While the low down lands provided the spatial condition for the extention of downtown of Suwon, the gneissic mountains have played the positive roles by high ecological dam effects with stable supply of water and purification of air, etc.

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Geology and Soil Environment of Jangdo Wetland, Heuksan-myon, Sinan-Gun, Cheollanamdo-province: A preliminary study (흑산도 지역 장도습지의 지질 및 토양환경: 예비조사)

  • Heo Chul-Ho;Kim Seong-Yong
    • Journal of the Korean earth science society
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    • v.26 no.7
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    • pp.661-667
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    • 2005
  • It was preliminarily considered that Jangdo wetland was a concave landform formed by the weathering of granite intruding Precambrian silicified metasedimentary rocks. Various granite-weathered topography was observed. The formation scenario of Jangdo wetland is as follows. By flood or slope mass movement of regolith, rock fragments were moved to form a low-relief slope landform. As a result, wetland was formed. By analyzing the slope soil and wetland sediment, we conjectured that Jangdo wetland depended on the influence of peripheral slope soil. In these concavelandform environment, the supply of water and organic materials was sustained for a long time to form a organicnondegradable wetland environment. In addition, the plants appropriate to this wetland environment were settled to thicken the wetland. This is how the present Jangdo wetland was thought to be formed.

The Damage Assessment, Construction Point of Time and Deterioration Diagnosis and Conservation Maintenance of Stone Statues Around the Stone Pagoda in Mireuksaji Temple in Iksan (익산 미륵사지 석탑 석인상의 조영시기와 훼손도 진단 및 보존관리)

  • Lee, Dong-sik;Lee, Yeon-gyeong
    • Korean Journal of Heritage: History & Science
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    • v.47 no.4
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    • pp.74-91
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    • 2014
  • The stone statues in the site of Mireuksaji Temple(Iksan, South Korea) were created after the stone pagoda was built in 639. They, transitional statues between animal sculptures and human shaped statues made from the late Goryeo dynasty until the early Joseon dynasty, were set up at the four corners of the stone pagoda by way of guardians. In the case of three statues, their surfaces were denudated and their iconographies have been indiscernible. However, the one in the southwest clearly shows its iconography. It is inferior in properties to the other three statues in the northwest, the northeast and the southeast respectively, but on the other hand its iconography has been well maintained. The reason is related to exposure to harmful environments; specifically, the retaining wall, built around the stone pagoda in the 17th century, had the southwest statue inside and could naturally worked as a buffer against harmful environments. As a result, for about 400 years there has been difference in weathering conditions between the three stone statues and the southwest statue, which brought denudation, the consequent indiscernibleness of iconography and biological invasion to the three statues, notwithstanding superior properties(northwest statue:$176kgf/cm^2$, northeast statue:$109kgf/cm^2$, southeast statue:$273kgf/cm^2$). In contrast, the southwest statue significantly shows its iconography with black contaminants and granule decomposition, despite inferior properties($133kgf/cm^2$). Defenseless exposure to external environment is not recommended for the stone statues, because it is hard to preserve the extant iconography. Herein lies the application of the data on microclimate around Mireuksaji Temple. As regards the weathering zone in which the stone statues are located, Conservation increases in acidity and frequency as years go by, Hereat, in the approach to the Conservation of stone statues, the first consideration needs to be morphological historicity rather than geographical location.

Failure Types in Rock Slopes According to Geological Characteristics (지질특성에 따른 암반사면 붕괴유형연구)

  • 정형식;유병옥
    • Geotechnical Engineering
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    • v.12 no.6
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    • pp.37-50
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    • 1996
  • In this study, we collected data through the investigation of rock slopes of highway. By analyzing the collected data, the main factors of rock slope failure were studied. We studied on the failure types and scales according to rock types and geological structures in many rock slopes of highway. As a result, it was shown that many failed slopes were distributed in the areas of Cretaceous sedimentary rocks of south-eastern part in the Korean Peninsula and the Gneiss Complex in both Kyonggi-Do and Kangwon-Do. According to rock types, the following slope failure types were shown : that igneous rocks had the types of rock fall, plane failure, soil erosion and circular failure but had low failure frequency, and sedimentary rocks had predominantly the type of plane failure. Metamorphic rock showed the types of circular failure, wedge failure and plane failure due to poor rock qualities . According to geological structures, the following slope failure types were shown slope failure in igneous rocks was caused by joints, and in sedimentary rocks by bedding plane, and in metamorphic rocks by faults and poor rock qualities.

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