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  • Title/Summary/Keyword: Mountain slope

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Investigation and Repair Methods for the Excavated Mountain Area damaged by Rainfall : At the Sunghak Campus, Dong-A University (호우로 인한 절개산지의 피해 조사 및 대책공법 -동아대 승학 캠퍼스를 중심으로-)

  • 정성교;김종대
    • Geotechnical Engineering
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    • v.7 no.2
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    • pp.27-40
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    • 1991
  • The Sunghak Campus, Dong-A University, which located at the excavated area of mountain, has been constructed year by year for about 10 years since 1978. The buildings, steep slopes, road and so on in the Campus area were damaged by heavy rainfall more than 200mm 1 day on August, 1989. The methods used for the investigation and repair methods of the damage are the preliminary investigation, the present condition survey, 50 by 50m grid survey, compasstraverse for locating outcrops, geopysical exploration, geologic survey, boring and laboratory soil testing. Based on the results of investigations, the causes of the failures have been evaluated, and the repair methods have been set up as horizontal drains, removal of the dangerous rock, retaining wall with subsurface drains, the elimination of colluvium and slope stabilization by use of precast concrete grids and so on.

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Analysis on Habitat Characteristics of the Korean Bats (Chiroptera) Using Geographic Information System (GIS)

  • Yoon, Kwang Bae;Lim, Sang Jin;Park, Yung Chul
    • Journal of Forest and Environmental Science
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    • v.32 no.4
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    • pp.377-383
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    • 2016
  • We obtained a total of 36 GPS coordinates of the seven bat species of Rhinolophus ferrumequinum, Myotis ikonnikovi, M. nattereri, M. petax, Murina ussuriensis, Plecotus auritus, and Pipistrellus abramus. Characteristics of forests (forest type, age class, DBH class and crown density), terrain (aspect, slope and distance from mountain stream) and disturbance factors (distance from human residential areas and distance from cultivated areas) that bats have used as their habitats were revealed from the GIS analysis based on GPS coordinates of the 36 positions that bats were found. The bats-preferred forest type is broad-leaf forests (43%) with the trees of the 2th (31%) and 5th (31%) age class, the trees of sapling (36%) and large DBH class (31%), and sparse crown density (67%). Bats prefer the slop direction of the east (39%), the gradient below 15 (61%), the ranges within 200 m from the mountain streams (92%), the ranges within 200 m near roads (89%), the ranges of 200-400 m from human residential areas (28%), and the ranges within 200 m from cultivated areas (36%).

Distribution Characteristics in the Habitat of Leptalina unicolor Population (은줄팔랑나비 개체군의 서식지 내 분포특성)

  • Hong, Sung-Jin;Yoon, Chun-Sik;Cheong, Seon-Woo
    • Journal of Environmental Science International
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    • v.28 no.12
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    • pp.1123-1131
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    • 2019
  • In this study, we investigated the spatial range, distribution pattern, temporal appearance, sex ratio, seasonal pattern, and size of the population of Leptalina unicolor locally inhabiting the wetland protection area in the Jaeyaksan Mountain. We found that the butterfly was distributed across four areas at 750 m above sea level and in an area of 96,000 ㎡. in the southeastern slope of the mountain. The discontinuous distribution of the butterflies in the meadow. According to our survey conducted from 2012 to 2014, L. unicolor occurred in May (spring) and July (summer) each year, with the male population more than three times higher than that of the female population. The population size estimated using the mark and recapture method on the back of the hind wing in the two years was as follows: 877±502 and 1243±800 individuals in the spring and summer of 2012, respectively, and 783±429 and 506±365 individuals in the spring and summer of 2014, respectively, suggesting no specific seasonal pattern. The findings of this study are expected to be useful for the conservation of the populations and habitats of L. unicolor, which are currently distributed locally due to a decrease in population size.

Characteristics of the Cheonhwangjae Paleolithic Site (천황재 구석기유적의 성격)

  • Kim, Woo rak;Seo, In seon
    • The Korean Journal of Quaternary Research
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    • v.34 no.2
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    • pp.27-32
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    • 2024
  • Cheonhwangjae Paleolithic site is the first highland ruins in Korea. An academic survey was conducted in this area to analyze the scope of the remains and the excavated stone tools. As a result of two on-site surveys, stone tools with blades and micro-blades were excavated from the mountain slope and flatland from Cheonhwangsan Mountain to Cheonhwangjae. The site are abundance in high-quality stone materials suitable for stone tools production on the road. Therefore, it is likely to have characteristics of quarry site and knapping workshop. And considering the amount and concentration of relics, it is presumed that it was not a one-off, but a continuous and long-term stoneware production site.

A Case Study on Reinforcement of Slope in PAP Retaining Wall using Back Analysis (PAP옹벽에서 역해석을 이용한 사면보강 사례 연구)

  • Kim, Jang-Deuk;Kim, Yong-Ha
    • The Journal of Engineering Geology
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    • v.19 no.3
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    • pp.345-350
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    • 2009
  • The endpoint of the Yangbuk tunnel constructed at the national road between Gyeongju and Gampo is composed of massive cutting because the road is driven through the sides of mountain. PAP(Prestressed Anchor and PC Pannel) retaining wall as a slope stability method was established over this section. Part of the anchor in PAP wall became broken after six months. We performed inverse analysis through its measurements obtained until that time. An geological investigation to confirm the condition of ground layering and the attraction force test to find as to whether some errors might be present in the anchor were made. According to the back analysis, it was turned out that the value with soil parameter 90% that was applied to the original design was pertinent. In the redesign, the permissible stress in the anchor body was changed from 306 kN to 591 kN and 784 kN and the fixation position was increased from 11.0 m to 23.0 m. Nevertheless, five months have passed since the exchange of the anchor, the measurement results validate that stable state has been maintained. This research is considered a case that the immediate maintenance helps prevent the slope accidents.

The Bicycle Road Route Selection which Considers the Slope Standard of the Bicycle Road (자전거도로의 경사기준을 고려한 자전거도로 노선 선정)

  • Baik, Seung-Heon;Han, Dong-Yeob;Jin, Hong-Seong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.6
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    • pp.553-559
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    • 2011
  • The bicycle use activation plan reduces a greenhouse gas exhaust, and economic convenience, movement timely shortening, health effect will be able to expect but the bicycle user is few. The nationwide bicycle road projects is advanced by the countermeasure for a bicycle use activation. It is advanced a bicycle road basic plan even from each local government. The research against a route selection is advanced actively. But the research against a data process is not coming out the accurate research method. It follows a financial one bicycle road design standard from ministry of land, Transport and maritime affairs. But vertical grade in bicycle road design standard is exception becoming that about unavoidable case with geomorphic environments. From the research which it sees the existing bicycle road consider should have to make the terrain situation of yeosu, slope standard connection about under considering it presented the bicycle road route selection which is possible. It included a lane and road width with additional element and establishment in the bicycle road was produced suitable bicycle road route. The area where the mountain district is many when selecting bicycle road, will be used with application plan of slope standard.

The Experimental Study for Variance of Depositation Due to Sediment Volume Concentration of Debris Flow (토석류의 토사체적농도에 따른 퇴적 특성 변화에 관한 실험 연구)

  • Choi, Youngdo;Kim, Sungduk;Lee, Hojin
    • Journal of Korean Society of Disaster and Security
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    • v.15 no.3
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    • pp.15-21
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    • 2022
  • The purpose of this study is to investigate the sedimentation area and runout distance in the downstream when debris flow occurred on a mountain slope through an experimental performance. Super typhoons and torrential rains caused by climate change cause large-scale debris flow disasters in the downstream areas of mountainous areas, mainly where sediments are deposited and flowed downstream. To analyze the characteristics of the sediment deposited downstream, the disposition area and runout distance were investigated through experiments in the case of a straight channel and channel with berm, respectively. As experimental conditions, changes in sediment volume concentration and channel slope, and channel with or without berm, reduction rates in sedimentation area and runout distance were investigated. In the straight channel, the steeper the channel slope and the lower the sedimentation concentration, the sedimentation area and runout distnace were increased. In a channel with berm, the runout distance and sediment area increased as the slope became steeper and the sediment area decreased.

Spatio-Temporal Variation of Soil Respiration and Its Association with Environmental Factors in Bluepine Forest of Western Bhutan

  • Cheten Thinley;Baghat Suberi;Rekha Chhetri
    • Journal of Forest and Environmental Science
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    • v.39 no.1
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    • pp.13-19
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    • 2023
  • We investigated Soil respiration in Bluepine forest of western Bhutan, in relation to soil temperature, moisture content and soil pH and it was aimed at establishing variability in space and time. The Bluepine forest thrives in the typical shallow dry valleys in the inter-montane Bhutan Himalaya, which is formed by ascending wind from the valley bottom, which carries moisture from the river away to the mountain ridges. Stratified random sampling was applied and the study site was classified into top, mid, low slope and further randomized sample of n=20 from 30 m×30 m from each altitude. The overall soil respiration mean for the forest was found 2248.17 CO2 g yr-1 and it is ~613.58 C g yr-1. The RS from three sites showed a marginal variation amongst sites, lower slope (2,309 m) was 4.64 μ mol m-2 s-1, mid slope (2,631 m) was 6.78 μ mol m-2 s-1 and top slope (3,027 m) was 6.33 μ mol m-2 s-1 and mean of 5.92 μ mol m-2 s-1, SE=0.25 for the forest. Temporal distribution and variations were observed more pronounced than in the space variation. Soil respiration was found highest during March and lowest in September. Soil temperature had almost inverse trend against soil respiration and dropped a low in February and peak in July. The moisture in the soil changed across months with precipitation and pH remained almost consistent across the period. The soil respiration and soil temperature had significant relationship R2=-0.61, p=0.027 and other variables were found insignificant. Similar relationship are reported for dry season in a tropical forest soil respiration. Soil temperature was found to have most pronounced effect on the soil respiration of the forest under study.

3D Slope Stability Analysis for Mountainous Areas Using the Limit Equilibrium Method (한계평형법에 의한 산지의 3차원 사면안정 해석)

  • Shin, Hosung;Choi, Sung-Kun
    • Journal of the Korean Geotechnical Society
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    • v.40 no.6
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    • pp.171-181
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    • 2024
  • This study aimed to enhance the precision of landslide hazard evaluation in complex mountainous terrains by addressing the limitations of the traditional 1D infinite slope stability method and employing the 3D limit equilibrium analysis of Shin's (2023) method. Soil depth distribution was estimated using DEM data combined with soil depth prediction formulas, and 3D slope stability analyses was performed under conditions of rainfall infiltration and static/pseudostatic forces. The assessment incorporated the factor of safety (FS) alongside a stability index (SI) that accounts for both FS and critical slip volume. A modified SI, integrating the influence of surrounding grid cells, was applied to visualize potential landslide-prone areas. In the case of landslides in the Umyeon mountain area, the predicted locations closely aligned with actual occurrences. Similarly, in Dongjak-gu, the staticc and pseudostatic analyses identified comparable high-risk zones. The proposed method demonstrates significant potential for accurately evaluating and predicting landslide risks. However, further field investigations and more detailed analyses are necessary to reconcile any discrepancies between numerical simulations and site-specific conditions.

Study on Suggestion a Standard Installation for Damage Reduction alarm System using Cut-Slope Data (국내 도로절개면 현황 및 붕괴 분석을 통한 경보시스템 설치 기준에 관한 기초적 연구)

  • Bae, Gyu-Jin;Koo, Ho-Bon;Baek, Yong
    • The Journal of Engineering Geology
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    • v.12 no.1
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    • pp.53-61
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    • 2002
  • Cut-slope due to the road construction is one of the most significant problems in the domestic case, that is, 70% of the land is covered by mountain. Moreover, typhoons or heavy rains concentrated in summer season causes the failure of cut-slope. Rock-fall and soil slope failure take 40.8% and 29.5% out of the entire domestic cut-slope failure, respectively. Rock-fall is quickly occurred by the free fall or rolling of rock fragments generally in the upper slope. Soil slope failure produces a clastics-flow and increases casualty especially when caused by heave rainfall because the velocity of the movement is verb high. Considering the car speed and rock-fall velocity, it will take a life in a moment. This study analyzes a set of field data of most recently collapsed domestic road cut-slopes to characterize these cut-slopes and the nature of rock-falls and clastics flows at each site. Based on the results, design criteria for a road alarm system are proposed, considering the relationship between the time required for clastics-flow and the velocity and braking distance of a cat at the incidence. The road alarm system proposed herein would operate instantly after a rock-fall and it will minimize damages, by warning drivels approaching to the collapse or collapsing location in advance.