• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.11 no.1
• /
• pp.29-35
• /
• 1993

The vegetation such as grass, shrub, tree has been used to control the erosion and stabilize the slope for a long time. But the effects of vegetation on slope area is usually neglected in traditional stability analyses. There are many errors in slope analyses in thin soil mantles. Therefore the effects of vegetation is an important factor. But it is difficult and complex to represent the vegetation influence quantitatively in stability analysis. In this study, authors choose the landslide region at the Kum sung dong Kum-jung ku Pusan as a model area. Authors analyzed the degree of slope with the aerial photo interpretation and DTM data extracted from the topographic map, and the relationship of D.B.H. (diameter of breast height), height, and age of tree in field investigation data. Finally authors know the fact that landslide take place approximately 10 or 20 years later in arbitrary afforestable area where the degree of slope is 27. The prevention effect must be considered in the control of vegetation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1639-1643
• /
• 2008

국내에서의 범람홍수 및 범람으로 인한 제방붕괴 특성은 그 해석상의 어려움으로 인해 주로 과거 범람상황 및 지형도를 통한 경험적 추정 등에 의존해 오고 있는 실정으로 정교한 물리학적 이론에 근거하지 못하였으므로 범람홍수량, 제방의 붕괴폭 등을 정확하게 예측하기에는 미흡한 점이 많았다. 도시하천과 같이 제방 인접한 곳에 주거, 산업시설 등이 밀집하고 있는 지역에서의 제방붕괴로 인한 홍수류의 범람은 막대한 인명 및 재산피해를 발생시키는 큰 재해가 될 수 있다. 본 연구를 통해서 홍수시 제방월류로 인한 제방붕괴 양상을 예측하고 이를 통해 범람유량의 정확한 예측을 통하여 도시하천 제방 계획시 홍수피해와 투자액을 감안한 경제적인 하천 제방단면 결정을 위한 기본자료로 활용될 수 있고, 도시 중요시설물의 입지 선정시 홍수피해에 대한 판단자료로 이용될 수 있을 것이다. 본 연구에서 개발된 모형을 이용하여 Teton 댐, Mantaro landslide 댐, Spirit Lake 장애물 댐 등에 적용하여 개발된 모형의 정확성을 입증하였다. 적용결과 개발된 모형은 기존의 모형과 같은 결과를 나타내어 국내 계산환경에 적용가능함을 보여 앞으로 이용가능성이 큰것을 알 수 있었다. 적용결과 파이핑의 발생위치의 영향은 대체로 파이핑의 위치가 제체의 윗부분에 위치할수록 최대 유출량은 커지는 것으로 나타났으나 Lawn Lake 댐의 경우에는 사면의 식생의 영향으로 다른 결과를 나타내었다. 점착력은 경우에는 점착력이 클수록 유출량의 크기는 감소하는 것으로 나타났으며 마찰각은 최대 붕괴폭의 크기 및 발생시간, 댐의 높이와 폭, 저수용량 등과 유출량이 연관있어 좀 더 많은 계산결과를 이용하여 심도있는 고찰이 요구되었다. 입자의 중간크기, 공극률, 균일성의 경우 적용된 댐들 모두 유사한 결과를 나타내었고 변수들이 커질수록 유출량도 증가하였다. 댐 사면 경사의 경우에는 상,하류 사면 모두 경사가 완만할수록 유출량이 감소하였다. 위의 결과를 통해 개발된 제방붕괴 해석모형은 좀 더 많은 연구와 적용을 통해 개선과 검증이 이루어진다면 국내 제방붕괴해석에 필요한 해석모형이 될 수 있다고 판단되었다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.105-105
• /
• 2020

전 세계적으로 기후변화에 따른 기온상승 및 강수량 증가, 호우일수 증가 등 이상기후로 인해 다양한 형태의 자연재해가 발생하고 있으며, 이로 인해 우리나라에서도 폭우, 풍랑, 가뭄, 대설 등으로 인한 자연재해 발생이 증가하고 있다. 특히 우리나라는 연평균 강수량 1,300mm의 대부분의 강우가 하절기인 6 ~ 9월에 태풍 및 집중호우를 동반하여 발생하기 때문에 연강수량의 60%이상이 여름철에 집중된다. 이러한 여름철에 집중된 강우로 인해 홍수 및 범람 피해가 여름철에 급증하고 있으며, 2차 피해인 산사태 및 토석류 피해 또한 급증하고 있는 추세이다. 토석류는 집중호우 시 자연산지의 취약한 사면이 붕괴되어 유출수와 함께 급경사의 계류로 붕괴된 토석이 유출되면서 토석류로 전이 및 발전하여 계류하부의 주택 및 농경지를 매몰하여 피해를 발생시킨다. 특히 토석류는 유출수와 함께 토석이 급경사의 계류를 따라 빠른 속도로 이동하고 퇴적 시작점에서 높이의 6배까지 이동하여 인명피해 등 큰 피해를 발생시키는 특성이 있다. 이러한 토석류 피해로 인한 피해와 손실을 최소화하기 위해서는 토석류 발생 시 피해 규모를 예측하여야하며, 또한 하부 구조물의 손실을 정량적으로 해석하여 방재정책의 우선순위를 수립하여야 한다. 따라서 본 논문에서는 강우로 인한 토석류 발생시 하부 구조물의 손실을 정량적으로 해석하기 위하여 토사재해 손실·손상함수를 개발하여, 함수를 탑재한 토사재해 피해액 산정모형인 DELET(DEbris flow Loss Estimation Tool) 모형을 개발하였다. DELET를 이용하여 실제 토석류 피해가 발생한 피해지역에 적용하여 토사재해 피해 구조물의 손실을 평가하였다.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.8
• /
• pp.67-75
• /
• 2004

The landslide is one of the most significant natural disasters, which cause a lot of loss of human lives and properties. The landslides in natural slopes generally occur by complicated problems such as soil properties, topography, and geology. Artificial Neural Network (ANN) model is efficient computing technique that is widely used to solve complicated problems in many research fields. In this paper, the ANN model with application of error back propagation method was proposed for estimation of landslide hazard in natural slope. This model can evaluate the possibility of landslide hazard with two different approaches: one considering only soil properties; the other considering soil properties, topography, and geology. In order to evaluate reasonably the landslide hazard, the SlideEval (Ver, 1.0) program was developed using the ANN model. The evaluation of slope stability using the ANN model shows a high accuracy. Especially, the prediction of landslides using the ANN model gives more stable and accurate results in the case of considering such factors as soil, topographic and geological properties together. As a result of comparison with the statistical analysis(Korea Institute of Geosciences and Mineral Resources, 2003), the analysis using the ANN model is approximately equal to the statistical analysis. Therefore, the SlideEval (Ver. 1.0) program using ANN model can predict landslides hazard and estimate the slope stability.

• Journal of Korean Society for Geospatial Information Science
• /
• v.15 no.4
• /
• pp.59-69
• /
• 2007

The scale of a natural disaster grows bigger and bigger every year. The government spends much of its budget on recovering the resulting damage on a national scale. It is important to shift the paradigm from taking measures after a disaster to that of taking preventive actions before a disaster in order to bring a fundamental resolution to such problems. In taking preventive actions and policies, it is necessary to integrate various kinds of advanced technologies including IT, high-tech information gathering technology and operational technology, and to predict and evaluate natural disasters on a comprehensive level. Although Korea is a country with a strong IT sector, most information gathering is still performed in paper. In particular, information about the areas of previous landslide occurrences and slopes remains on paper, which makes it difficult to share the information and to discern the contents, and also raises the possibility of missing documents. Thus this study set out to develop an information gathering and management system for cutting slopes using PDA from the perspective of information gathering, system compatibility, and information management. As a result, field information may be gathered in a variety of forms (location, photos, and texts) real-time. A rough judgment was also made of the stability of rock slopes using the SMR method on the field.

• Journal of Korean Society of Forest Science
• /
• v.110 no.1
• /
• pp.64-71
• /
• 2021

Recently, climate change has gradually accelerated the occurrence of landslides. Among the various effects caused by landslides,debris flow is recognized as particularly threatening because of its high speed and propagating distance. In this study, the impacts of various factors were analyzed using quantification theory(I) for the prediction of debris flow hazard soil volume in Seoraksan National Park, Korea. According to the range using the stepwise regression analysis, the order of impact factors was as follows: vertical slope (0.9676), cross slope (0.6876), altitude (0.2356), slope gradient (0.1590), and aspect (0.1364). The extent of the normalized score using the five-factor categories was 0 to 2.1864, with the median score being 1.0932. The prediction criteria for debris flow occurrence based on the normalized score were divided into four grades: class I, >1.6399; class II, 1.0932-1.6398; class III, 0.5466-1.0931; and class IV, <0.5465. Predictions of debris flow occurrence appeared to be relatively accurate (86.3%) for classes I and II. Therefore, the prediction criteria for debris flow will be useful for judging the dangerousness of slopes.

• Economic and Environmental Geology
• /
• v.43 no.4
• /
• pp.381-391
• /
• 2010

Probabilistic prediction methods of landslides which have been developed in recent can be reliable with premise of detailed survey and analysis based on deep and special knowledge. However, landslide susceptibility should also be analyzed with some reliable and simple methods by various people such as government officials and engineering geologists who do not have deep statistical knowledge at the moment of hazards. Therefore, this study suggests an evaluation chart of landslide susceptibility with high reliability drawn by accurate statistical approaches, which the chart can be understood easily and utilized for both specialists and non-specialists. The evaluation chart was developed by a quantification method based on canonical correlation analysis using the data of geology, topography, and soil property of landslides in Korea. This study analyzed field data and laboratory test results and determined influential factors and rating values of each factor. The quantification analysis result shows that slope angle has the highest significance among the factors and elevation, permeability coefficient, porosity, lithology, and dry density are important in descending order. Based on the score assigned to each evaluation factor, an evaluation chart of landslide susceptibility was developed with rating values in each class of a factor. It is possible for an analyst to identify susceptibility degree of a landslide by checking each property of an evaluation factor and calculating sum of the rating values. This result can also be used to draw landslide susceptibility maps based on GIS techniques.

• Journal of the Korean GEO-environmental Society
• /
• v.14 no.11
• /
• pp.5-12
• /
• 2013

The purpose of this study is to estimate the behavior and the mechanism of debris flow at the end of mountain side when a berm was set on the inclined plane. The numerical model was performed by using the Finite Difference Method(FDM) based on the equation for the mass conservation and momentum conservation. In order to measure the behavior of the debris flow, the debris flow of a straight channel slope and the debris flow of channel slope with 3 types of berms were compared. First, the flow discharge and the sediment volume concentration at the downstream of the channel slope, depending on the various berm width and the different inflow discharges at the upstream of the channel were analyzed. The longer the berm width, the flow discharge at the downstream of the channel was decreased and the high flow fluctuation was reduced by a berm. And it means that a berm can effect for the delay of the debris flow. Through Root Mean Square ratio(RMS) comparison, the flow discharge of the channel slope with a berm was lower than that of a straight channel slope. The longer the berm width, for the sediment volume concentration, an inflection point did not show but mild curve. Because the low sediment concentration with water mixture by a berm continuously flow at the downstream end, it will be effect for reducing the disaster caused by debris flow. The results of this study will provide useful information in predicting and preventing disaster caused by the debris flow.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.192-192
• /
• 2021

산지 사면에서 발생한 토석류는 지형변화에 큰 영향을 미치는 대표적인 자연재해이다. 특히, 집중호우로 인해 발생하는 산사태의 경우 단시간에 많은 토사가 붕괴되며, 이는 매우 빠른 속도로 유동하는 토석류로 발전할 수 있다. 이러한 토석류가 도심지역에서 발생할 경우 많은 인명 및 재산피해를 야기하며, 이와 같은 피해를 저감하기 위해선 토석류의 유동과 피해규모를 예측할 수 있는 수치모형을 통한 연구가 필수적으로 이루어져야한다. 유동 및 퇴적지역의 피해규모를 크게 증가시킬 수 있는 침식-연행작용에 대한 연구는 최근에 활발히 이루어지고 있다. 수치모형으로 분석된 피해범위와 규모를 정밀하게 산정하기 위해선 침적과정에 대한 구현·해석이 필요하나 국내·외적으로 토석류 침적에 대한 연구는 미비한인 실정이다. 이에 본 연구는 침적을 고려하는 침식-연행작용 모형을 개발하여 토석류의 유동 및 퇴적과정을 자연현상에 가깝게 묘사하고자 하였다. 해당 모형은 2011년 우면산 일대에서 발생한 일련의 토석류를 대상으로 검증하고자하며, 연구지역의 지형 및 붕괴지점 자료는 토석류 발생 전·후 DEMs(Digital Elevation Models)을 이용하여 구축하였다. 현장에서 관측된 피해 범위, 총퇴적량, 특정 지점에서의 최대 피해 높이와 첨두속도 등은 실측자료로 활용하여 모형의 결과와 비교·분석하였으며 이를 통해 모형의 성능을 검증하고자 하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.32 no.5
• /
• pp.515-525
• /
• 2014

Recently, because of increasing in downpour and typhoon, which are caused by climate changes, those sedimentation disasters, such as landslide and debris flow, have become frequent. Those sedimentation disasters take place in natural slope. In order to predict debris flow damage range within wide area, the response model is more appropriate than numerical analysis. However, to make a prediction using Random Walk Model, the regional parameters is needed to be decided, since the regional environments conditions are not always same. This random Walk Model is a probability model with easy calculation method, and simplified slope factor. The objective of this study is to calculate the optimal parameters of Random Walk Model for Umyeon mountain in Seoul, where the large debris flow has occurred in 2011. Debris flow initiation zones and sedimentation zones were extracted through field survey, aerial photograph and visual reading of debris flow before and after its occurrence via LiDAR DEM.