• 한국안전학회지
• /
• 제30권3호
• /
• pp.52-58
• /
• 2015

As sudden rainfall has happened, the debris flow has occurred in the mountain area. Recently sudden rainfall occurred so frequently caused by abnormal climate. Thus debris flow hazard had consecutively increased damage because of debris flow. Recently, Enormous damage due to debris flow have occurred in Korea. Various studies have been conducted to prevent search debris flow hazard. This study was carried out for debris flow behavior according to the land slope on propagation. It is the important one among factors that are related to the propagation over the city with respect to debris flow discharge and depth. For the numerical simulations in this study, the land slope was varied of 5, 0, $-5^{\circ}$ to investigate the debris flow behavior with the FLO-2D, often recommended by FEMA to simulate debris flow. To verify the performance of FLO-2D, comparison with the USGS experiments (Iverson et al, 2010) was conducted. From numerical results the propagation length of the debris flow was found the most sensitive one. Maximum of debris flow thickness and velocity and structural vulnerabilities were investigated to the effect of land slope. They was became smaller according to land slope of 5, -5, $0^{\circ}$ in the order. As a result, debris flow behavior analysis about the effect of the land slope could contribute to understand the vulnerability of city for debris flow hazards.

• 지질공학
• /
• 제28권3호
• /
• pp.341-348
• /
• 2018

Landslides can be caused by localized intense rainfall. The loss of human lives and damage to property from landslides is increasing. However, little information exists on the movement and flow of sediment material at the time of rapid landslides. In this study, a field survey was conducted of landslides that occurred in 2013 in the Hadari area of Yeoju city in Korea. This was followed by numerical analysis. The purpose is to analyze the characteristics of a consequent debris flow and its movement at the time of failure. The results of the field survey and numerical analysis are consistent with each other. The maximum velocity of the debris flow was ~9.335 m/s and the maximum sediment thickness ~4.674 m. The latter is similar to the traces of debris flow observed in the field.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2008년도 정기총회 및 학술발표대회
• /
• pp.707-710
• /
• 2008

Recently, a rivers' bridge that locate on among the mountains area is destroyed by debris accumulation and debris flow, because of frequent occurrence of typhoon and a localized torrential downpour. therefore a river make a part of dam's effect. Actually, this situation gives damages like inundation of a bridge upper stream area's. Generally, It the main cause of the occurrence route of the debris accumulation is that outbreaks of driftwood and debris flow because of landslide, that occurred by severe rain storm. Also, a lot of debris are occurred when big flood come up during long period at this time, this kind of debris accumulation remove to other place, in several, and specially, debris accumlation move to the place where the depth of water is deep and velocity is fast river center. According to these kind of fact, this research put in effect and analyze that movement characteristic's numerical simulations of debris accumulation at flood according to a domestic outside literature investigation, on-site monitoring survey and parameter scenario which comes out through the hydraulic modeling analysis.

• 한국환경복원기술학회지
• /
• 제13권4호
• /
• pp.52-64
• /
• 2010

This study was carried out to analyze the occurrence characteristics and the influence of forest environment factors on the debris flow of 3 national parks in korea. The results obtained from this study were summarized as follows; The total number of debris flow occurrence was 125 areas. The average length of the debris flow scar was 144m, average width was 20m. And the average area and sediment were $2,854m^2$ and $3,959m^3$ respectively. The factors influencing the debris flow were highly occurred in Metamorphic rock, mixed forest type. And also, slope gradient was $30{\sim}35^{\circ}$, aspect was NE, altitude was over 1,000m, vertical and cross slope was concave (凹), soil depth was below 15cm, stream order was 0 order. The variables of cross slope (complex), deciduous tree, soil depth (over 46cm), cross slope (concave), mixed forest type and altitude (801~1200m) in correlation analysis were significant at 1 % level. The landslide of high mountain area highly tend to change the debris flow in stream bed of torrent. The debris flow in national parks mainly occurred in high mountain area with long ridge and steep slope.

• 대한공간정보학회지
• /
• 제24권2호
• /
• pp.15-24
• /
• 2016

This study conducted an evaluation of the extent of debris flow damage using SINMAP, which is slope stability analysis software based on the infinite slope stability method, and FLO-2D, a hydraulic debris flow analysis program. Mt. Majeok located in Chuncheon city in the Gangwon province was selected as the study area to compare the study results with an actual 2011 case. The stability of the slope was evaluated using a DEM of $1{\times}1m$ resolution based on the LiDAR survey method, and the initiation points of the debris flow were estimated by analyzing the overlaps with the drainage network, based on watershed analysis. In addition, the study used measured data from the actual case in the simulation instead of existing empirical equations to obtain simulation results with high reliability. The simulation results for the impact of the debris flow showed a 2.2-29.6% difference from the measured data. The results suggest that the extent of damage can be effectively estimated if the parameter setting for the models and the debris flow initiation point estimation are based on measured data. It is expected that the evaluation method of this study can be used in the future as a useful hazard mapping technique among GIS-based risk mapping techniques.

• 지질공학
• /
• 제32권4호
• /
• pp.547-558
• /
• 2022

2020년 8월 집중호우로 인하여 전라남도 곡성지역에 토석류가 발생하여 5명이 사망하는 재난이 발생하였다. 이 지역을 대상으로 하여 사진 측량을 통해 0.03 m의 고해상도 지형정보를 구축하고 토사의 붕괴량을 측정하였다. 또한 Flo-2D를 이용하여 토석류의 유량과 지형정보의 차이에 따라 유동심, 유속, 확산면적에 대하여 민감도 분석을 수행하였다. 유량이 높아질수록 토석류의 유동심, 유속, 확산면적이 높아지며 고해상도 지형정보와 저해상도 지형정보와의 결과 차이도 높아지는 것으로 나타났다. 그리고, 고해상도의 지형정보를 적용하였을 때 실제의 토석류 흐름방향과 유사하게 계산되어 고해상도 지형정보의 적용이 토석류 해석 결과의 정확성을 높이는 결과를 정량적으로 분석하였다. 추가로 항복응력과 점성과 같은 지질정보에 대해 고려하면 전반적으로 실제 토석류의 확산 정보보다 작게 계산된 결과를 보완할 수 있을 것으로 판단된다.

• 한국지반환경공학회 논문집
• /
• 제16권3호
• /
• pp.49-55
• /
• 2015

토석류가 발생할 때는 강우패턴, 강우강도 및 해석을 위한 지형여건에 따라 토석류의 발생량과 흐름의 속도가 달라진다. 지형여건의 고려는 일정규모의 격자로 지형을 구분하고 구분된 격자 내의 지형경사는 평균경사로 가정하여 계산하므로 굴곡이 심한 지형에서는 분할되는 격자를 세분할수록 실제와 근접한 결과를 얻을 수 있게 된다. 그러나 지금까지는 해석알고리즘 및 컴퓨터 계산능력, 해석수행 시간 등의 한계로 인해 지형분할 격자를 상당히 크게 구분하여 수행하고 있다. 그러나 토석류 해석의 정확도를 위해서는 지형구분 격자크기를 가급적 작게 하여야 하므로, 실무적 접근을 위한 적절한 격자규모의 제안이 필요하게 된다. 따라서 본 논문에서는 기존 연구에서 논의되었던 누가 강우량, 강우강도, 강우지속시간 및 선행 강우량 등의 강우 특성 이외에 지형분할 격자크기가 토석류 흐름에 미치는 영향을 평가하고 이로부터 합리적이고 현실성 있는 지형분할규모를 제시하였다.

• 한국안전학회지
• /
• 제33권4호
• /
• pp.84-89
• /
• 2018

The number of landslides has increased since the 2000s due to the increased frequency of heavy rainfall caused by abnormal weather. A variety of debris flow prevention facilities have been installed as a countermeasure against this problem. However, it is not easy to evaluate the efficiency of debris flow prevention structures except for the structures with constant volume such as the erosion dam, because the other structures are limited to be reproduced in simulation program for debris flow. Therefore, the methods by which the debris flow prevention structures were modeled were proposed, and the efficiency of four prevention structures installed in Baekyang Mt. in Busan was evaluated with UDS, which accuracy had been verified, using these methods. The initial amount of debris flow was determined based on landslide which occurred in 2014, and specifications of the complex retaining walls around the settlements were measured and applied modeling for terrain. The numerical results showed that the efficiency of debris flow prevention structures could be quantitatively presented. Among the debris flow prevention structures installed in Baekyang Mt., prevention structure of barrier type for debris flow was the most efficiency and debris flow prevention device was the lowest efficiency when the only depth of debris was evaluated. It seems that this study is meaningful to propose the methods which were used to model the debris flow prevention structures that could not be reproduced in most 2D debris flow numerical analysis programs. If precise verification of the presented methods is carried out, it will be possible to provide clear criteria for the efficiency evaluation method of disaster prevention structures.

• 대한공간정보학회지
• /
• 제24권3호
• /
• pp.59-66
• /
• 2016

2011년 발생한 서울시 우면산의 토석류는 과거 산간지역 피해와는 달리 도심지역에서 큰 피해가 발생하였다. 따라서 산사태 및 토석류는 산악지역과 도심지역에 관계없이 다양한 지역에서 빠른 속도로 발생하여 엄청난 피해를 유발시키기 때문에 많은 연구자들은 토석류의 영향범위를 예측하고 피해를 최소화하기 위해 노력하고 있다. 토석류의 영향범위 예측을 위한 가장 핵심적인 부분은 복잡한 3차원 지형에서의 토석류 거동 및 퇴적 메커니즘을 이해하여야 한다. 그리고 퇴적 메커니즘을 이해하기 위해서는 토석류의 거동에 따른 에너지량과 침식량이 산정되어야 한다. 하지만 기존에 개발된 토석류 모델들은 토석류의 침식량을 산정하는데 한계가 있었다. 따라서 본 연구에서는 2011년 도심지의 대규모 토석류가 발생한 서울시 우면산 지역을 대상으로 항공사진, 항공 LiDAR 자료로부터 생성된 토석류 피해 전과 후의 DEM을 활용하여 토석류의 피해규모를 산정하였으며, 에너지 이론을 기반으로 하여 침식량을 산정할 수 있는 토석류 거동 해석 모델을 개발하여 비교하였다. 또한 동일지역에 대하여 기존의 토석류 모델(RWM, Debris 2D)도 함께 시뮬레이션 하여 종합적으로 토석류 지역을 비교 분석하였다.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2016년도 춘계 종합학술대회 논문집
• /
• pp.241-242
• /
• 2016

Recent abnormal climate change induces localized heavy rainfall and extreme disasters such as debris flow near urban area. Thus many researches have been conducted to estimate and prevent, especially in focus of physical behavior of debris flow. Even though it is hardly to consider overall related parameters to estimate the extent and degree of directly or indirectly damages due to debris flow. Those analytic restraint would be caused by the diversity and complexity of regional topographic and hydrodynamic characteristics of debris flow inside. We have utilized the Bayesian method to compensate the uncertainty due to the complex characteristics of it after analyzing the numerical results from FLO-2D and field measurement data. Revised values by field measurements will enhance the numerical results and the missing parameters during numerical simulation will be supplemented with this methodology. As a final outcome in this study, the risk index of debris flow damage will be suggested to provide quantitative estimation in terms of hazard protection including the impact on buildings, especially in inner and outer of urban area.