• 제목/요약/키워드: SLOPE ASPECT

검색결과 353건 처리시간 0.028초

Assessment of seismic stability of finite slope in c-ϕ soils - a plasticity approach

  • Shibsankar, Nandi;G., Santhoshkumar ;Priyanka, Ghosh
    • Geomechanics and Engineering
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    • 제31권5호
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    • pp.439-452
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    • 2022
  • A forecast of slope behavior during catastrophic events, such as earthquakes is crucial to recognize the risk of slope failure. This paper endeavors to eliminate the significant supposition of predefined slip surfaces in the slope stability analysis, which questions the relevance of simple conventional methods under seismic conditions. To overcome such limitations, a methodology dependent on the slip line hypothesis, which permits an automatic generation of slip surfaces, is embraced to trace the extreme slope face under static and seismic conditions. The effect of earthquakes is considered using the pseudo-static approach. The current outcomes developed from a parametric study endorse a non-linear slope surface as the extreme profile, which is in accordance with the geomorphological aspect of slopes. The proposed methodology is compared with the finite element limit analysis to ensure credibility. Through the design charts obtained from the current investigation, the stability of slopes can be assessed under seismic conditions. It can be observed that the extreme slope profile demands a flat configuration to endure the condition of the limiting equilibrium at a higher level of seismicity. However, a concurrent enhancement in the shear strength of the slope medium suppresses this tendency by offering greater resistance to the seismic inertial forces induced in the medium. Unlike the traditional linear slopes, the extreme slope profiles mostly exhibit a steeper layout over a significant part of the slope height, thus ensuring a more optimized solution to the slope stability problem. Further, the susceptibility of the Longnan slope failure in the Huining-Wudu seismic belt is predicted using the current plasticity approach, which is found to be in close agreement with a case study reported in the literature. Finally, the concept of equivalent single or multi-tiered planar slopes is explored through an example problem, which exhibits the appropriateness of the proposed non-linear slope geometry under actual field conditions.

Transport and Decomposition of Leaf Litter as Affected by Aspect and Understory in a Temperate Hardwood Forest

  • Yoo, Gayoung;Park, Eun-Jin;Kim, Sun-Hee;Lee, Hye-Jin;Kang, Sinkyu;Lee, Dowon
    • Animal cells and systems
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    • 제5권4호
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    • pp.319-325
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    • 2001
  • Transport of colored papers and decomposition of leaf litter of Quercus mongolica, Acer pseudo-sieboldianum, and Kalopanax pictus were investigated on three patches differentiated by aspect and understory in a temperate hardwood forest. Two patches are represented by dwarf bamboo (Patch SS) and herbaceous plants (Patch S), respectively, Iying on a south-west-facing slope. The other patch (Patch N) is located on a northeastfacing slope with herbaceous plants. Colored papers were placed on the patches to understand the pattern of litter movement on the ground. Papers were move dispersed in Patch S than in the other two patches. Some of the colored papers placed in Patch S moved upward. The results suggest that the litter movement is affected by aspect and that the leaf litter is retained by dwarf bamboo in Patch SS. Decay constant of Q. mongolica was significantly (p<0.05) lower than those of K. pictus and A. pseudo-sieboldianum. Decay rates of Q. mongolica were significantly different between Patches N and S and between Patches SS and S (p<0.05). On the other hand, decay rates of the other species were not significantly different among the three patches. The results suggest that aspect and understory exert an influence on redistribution and decomposition of leaf litter and that the effects could be different among the plant species.

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충남 천안 백석동 청동기 시대 주거지 밀집 구역의 지형 환경 (Geomorphological Environments of High-density Residential Zone in Baekseokdong, Cheonan, Chungnam in the Bronze Age)

  • 박종철;박지훈
    • 한국지역지리학회지
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    • 제17권3호
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    • pp.297-312
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    • 2011
  • 현재까지 발굴된 고고 유적을 대상으로 고대 취락의 분포 및 입지 특성을 이해하는 것은 고대 취락의 형성과 소멸과정을 밝히기 위한 기초 연구에 해당한다는 점에서 의의가 있다. 지금까지 대부분의 연구들은 개별 주거지의 입지 환경에 관심을 가졌다. 하지만 본 연구에서는 주거지가 밀집한 구역의 지형 환경을 밝히고자 하였다. 연구지역은 충남 천안시에 위치한 백석동유적그룹이며, 이 지역에서 발굴된 205기의 청동기 시대 주거지를 연구대상으로 하였다. 이 연구에서 고려한 지형 환경은 사면 미지형, 지형경사, 사면방향이다. 연구지역에서 청동기 시대 주거지가 밀집한 주거지 밀집 구역의 지형 환경은 주로 정부사면 또는 정부평탄면의 파랑성 평야~준완경사지, 남향(남동향-남향-남서향) 사면으로 구성되어 있었다.

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공간정보 기반 산사태 발생지역 예측비율 평가 (The Evaluation on the Prediction Ratio of Landslide Hazard Area based on Geospatial Information)

  • 이근상;이호준;고신영;조기성
    • 지적과 국토정보
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    • 제44권2호
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    • pp.113-124
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    • 2014
  • 최근 집중호우에 의한 산사태 발생이 빈번해짐에 따라 산사태 취약지역을 분석하고 산사태 발생을 예측하기 위한 다양한 연구들이 진행되고 있다. 본 연구에서는 산사태 발생지역의 토양특성을 분석하였으며, 배수 특성별 우도비를 평가한 결과 배수가 좋은 토양에서 산사태 발생 가능성이 높게 나타났다. 또한 DEM 자료에서 추출한 경사도의 우도비를 평가한 결과 $20{\sim}40^{\circ}$ 경사구간에서 산사태 발생 가능성이 높게 나타났다. 그리고 공간분석에 의한 사면방향도의 우도비를 평가한 결과 북향에서 산사태 발생 가능성이 높게 나타났다. 아울러 토양배수, 경사도 그리고 사면방향도의 우도비를 중첩하여 산사태 취약도를 평가할 수 있었으며, 산사태 발생지역에 대하여 분석과 검증 프로세스를 수행함으로써 미래 산사태 발생 예측비율을 평가할 수 있었다.

묘지의 분광적 특성과 통계적 분류 (Spectral Signatures of Tombs and their Classification)

  • Eunmi Change;Kyeong Park;Minho Kim
    • 대한지리학회지
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    • 제39권2호
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    • pp.283-296
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    • 2004
  • 화장의 증가에도 불구하고 묘지의 면적증가는 계속되고 있고 이로 인해 국토공간 가운데 산지를 효율적으로 활용하지 못하고 있는 것이 현실이다. 위성영상을 이용한 사상추출(feature extraction) 방법은 이러한 문제점을 해결하고 묘지의 체계적인 관리를 가능하게 할 것으로 기대할 수 있다. 이에 본 연구에서는 묘지의 반자동 혹은 자동추출을 위한 기초연구로서 묘지의 통계적인 분광특성과 유형분류에 관한 연구를 수행하였다. 연구를 위해 고해상도 위성영상인 IKONOS 영상을 이용하였다. 연구지역 내에서 24개의 대상묘지를 선정하여 해당 묘지의 통계적 분광특성을 조사하고, 경관 식생지수 군집분석 등에 의한 분류를 시도하였다. 그리고 사면이나 경사도가 묘지의 유형구분에 미치는 영향을 연구하였다. 연구결과, 식생지수와 군집분석에 의한 유형구분이 유사하게 나타났고 사면이나 경사도는 묘지의 유형구분에 큰 영향을 미치지 않는 것으로 나타났다.

산림환경 및 하천형태인자에 의한 유역안정성 평가 (Evaluation of Watershed Stability by the Forest Environmental and Stream Morphological Factors)

  • 정원옥;마호섭
    • 한국환경복원기술학회지
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    • 제4권4호
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    • pp.1-11
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    • 2001
  • This study was carried out to analyze the characteristics of forest environmental and stream morphological factors by using the quantification theory(I) for evaluation of the watershed stability. Present annual mean sediment yield of erosion control dams were investigated in 167 sites of erosion control dam constructed during 1986 to 1999 in Gyeongbuk. The results obtained from this study were summarized as follows; According to the coefficients of partial correlation, each factor affecting to sediment was shown in order of gravel contents, number of first streams order, number of total streams, length of total streams, forest type, length of main stream, parent rock, stand age, soil texture, stream order, slope gradient, soil depth and aspect. Descriptions of class I were as follow; Igneous rock of parent rock, hardwood stands of forest type, less than 20 year of stand age, less than 30cm of soil depth, sandy clay loam of soil texture, more than 41% of gravel contents, south~east of aspect, 2,501~3,500m of length of main stream, 21~25 of number of total streams, 5,501~10,000m of length of total streams, 3 or more than 4 of stream order, more than 16 of number of first stream orders and more than $31^{\circ}$ of slope gradient. Descriptions of class II were as follow; Metamorphic rock of parent rock, coniferous stands of forest type, more than 25 year of stand age, 31~40cm of soil depth, silt loam of soil texture, 11~20% of gravel contents, north~west of aspect, 2,501~3,500m of length of main stream, 16~20 of number of total streams, 3,501~5,500m of length of total streams, 3 of stream order, 11~15 of number of first stream orders and more than $31^{\circ}$ of slope gradient. Descriptions of class III were as follow; Sedimentary rock of parent rock, mixed stands of forest type, more than 25 year of stand age, more than 51cm of soil depth, silty clay loam of soil texture, less than 10% of gravel contents, south~west of aspect, less than 500m of length of main stream, less than 5 of number of total streams, less than 1,000m of length of total streams, less than 1 of stream order, less than 2 of number of first stream orders and less than $25^{\circ}$ of slope gradient. The prediction method of suitable site for erosion control dam divided into class I, II, and III for the convenience of use. The score of class I evaluated as a very unstable area was more than 8.4494. A score of class II was 8.4493 to 6.0452, it was evaluated as a moderate stable area, and class III was less than 6.0541, it was evaluated as a very stable area.

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