scholarly journals Simulation of Debris-Flow Runout Near a Construction Site in Korea

2020 ◽  
Vol 10 (17) ◽  
pp. 6079 ◽  
Author(s):  
Byung-Gon Chae ◽  
Ying-Hsin Wu ◽  
Ko-Fei Liu ◽  
Junghae Choi ◽  
Hyuck-Jin Park
Keyword(s):  
Debris Flow ◽  
Landslide Susceptibility ◽  
Debris Flows ◽  
Source Area ◽  
Flow Path ◽  
Construction Site ◽  
Landslide Prediction ◽  
Runout Distance ◽  
Susceptibility Analysis

This study analyzed landslide susceptibility and numerically simulated the runout distance of debris flows near a construction site in Korea. Landslide susceptibility was based on a landslide prediction map of the study area. In the prediction map, 3.5% of the area had a 70–90% landslide probability, while 0.79% had over 90% probability. Based on the landslide susceptibility analysis, debris flows in four watersheds were simulated to assess possible damage to the construction site. According to the simulations, debris flow in Watershed C approaches to within 9.6 m of the site. Therefore, the construction site could be impacted by debris flow in Watershed C. Although the simulated flows in Watersheds A and D do not directly influence the construction site, they could damage the nearby road and other facilities. The simulations also show that debris runout distance is strongly influenced by the volume of debris in the on-slope source area and by the slope angles along the debris-flow path.

scholarly journals Parameterization of a numerical 2-D debris flow model with entrainment: a case study of the Faucon catchment, Southern French Alps

2012 ◽  
Vol 12 (10) ◽  
pp. 3075-3090 ◽  
Author(s):  
H. Y. Hussin ◽  
B. Quan Luna ◽  
C. J. van Westen ◽  
M. Christen ◽  
J.-P. Malet ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Debris Flow ◽  
Debris Flows ◽  
Source Area ◽  
European Alps ◽  
Actual Process ◽  
French Alps ◽  
Modeling Software ◽  
Entrainment Process

Abstract. The occurrence of debris flows has been recorded for more than a century in the European Alps, accounting for the risk to settlements and other human infrastructure that have led to death, building damage and traffic disruptions. One of the difficulties in the quantitative hazard assessment of debris flows is estimating the run-out behavior, which includes the run-out distance and the related hazard intensities like the height and velocity of a debris flow. In addition, as observed in the French Alps, the process of entrainment of material during the run-out can be 10–50 times in volume with respect to the initially mobilized mass triggered at the source area. The entrainment process is evidently an important factor that can further determine the magnitude and intensity of debris flows. Research on numerical modeling of debris flow entrainment is still ongoing and involves some difficulties. This is partly due to our lack of knowledge of the actual process of the uptake and incorporation of material and due the effect of entrainment on the final behavior of a debris flow. Therefore, it is important to model the effects of this key erosional process on the formation of run-outs and related intensities. In this study we analyzed a debris flow with high entrainment rates that occurred in 2003 at the Faucon catchment in the Barcelonnette Basin (Southern French Alps). The historic event was back-analyzed using the Voellmy rheology and an entrainment model imbedded in the RAMMS 2-D numerical modeling software. A sensitivity analysis of the rheological and entrainment parameters was carried out and the effects of modeling with entrainment on the debris flow run-out, height and velocity were assessed.

scholarly journals Classification and susceptibility assessment of debris flow based on a semi-quantitative method combining of the fuzzy C-means algorithm, factor analysis and efficacy coefficient

2020 ◽  
Author(s):  
Zhu Liang ◽  
Changming Wang ◽  
Songling Han ◽  
Kaleem Ullah Jan Khan ◽  
Yiao Liu
Keyword(s):  
Factor Analysis ◽  
Debris Flow ◽  
Human Activity ◽  
Land Use Planning ◽  
Debris Flows ◽  
Field Investigation ◽  
Matter Source ◽  
Susceptibility Analysis ◽  
Fuzzy C Means ◽  
Fuzzy C Means Algorithm

Abstract. The existence of debris flows not only destroys the facilities, but also seriously threatens human lives, especially in scenic areas. Therefore, the classification and susceptibility analysis of debris flow are particularly important. In this paper, 21 debris flow catchments located in Huangsongyu town ship, Pinggu District of Beijing, China were investigated. Besides field investigation, geographic information system, global positioning system and remote sensing technology were applied to determine the characteristics of debris flows. This article introduced clustering validity index to determine the clustering number, and the fuzzy C-means algorithm and factor analysis method were combined to classify 21 debris flow catchments in the study area. The results were divided into four types: scale-topography-human activity closely related, topography-human activity-matter source closely related, scale-matter source-geology closely related and topography-scale-matter source-human activity closely related debris flow. And 9 major factors screened from the classification result were selected for susceptibility analysis, using both the efficacy coefficient method and the combination weighting. Susceptibility results showed that the susceptibility of 2 debris flows catchments were high, 6 were moderate, and 13 were low. The assessment results were consistent with the field investigation. Finally, a comprehensive assessment including classification and susceptibility evaluation of debris flow was obtained, which was useful for risk mitigation and land use planning in the study area, and provided reference for the research on related issues in other areas.

scholarly journals A multivariate statistical method for susceptibility analysis of the debris flow in Southwest China

2019 ◽  
Author(s):  
Feng Ji ◽  
Zili Dai
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Loose Material ◽  
Southwest China ◽  
Quantitative Prediction ◽  
The Tibetan Plateau ◽  
Type I ◽  
Quantification Theory ◽  
Susceptibility Analysis ◽  
Dadu River

Abstract. Southwest China is characterized by many steep mountains and deep valleys due to the uplift activity of the Tibetan Plateau. The 2008 Wenchuan Earthquake left large amounts of loose materials in this area, making it a severe disaster zone in terms of debris flow. Susceptibility is a significant factor of debris flow for evaluating its formation and impact. Therefore, it is in urgent need to analyze the susceptibility of debris flows in this area. At present, the susceptibility analysis models of the debris flow in Southwest China is mainly based on qualitative methods. Little quantitative prediction model is found in the literature. This study evaluates 70 typical debris flow gullies as statistical samples, which are distributed along the Brahmaputra River, Nujiang River, Yalong River, Dadu River, and Ming River respectively. Nine indexes are chosen to construct a factor index system and then to evaluate the susceptibility of debris flow. They are the catchment area, longitudinal grade, average gradient of the slope on both sides of the gully, catchment morphology, valley slope orientation, loose material reserves, location of the main loose material, antecedent precipitation, and rainfall intensity. Then, an empirical model based on the quantification theory type I is established for the susceptibility prediction of debris flows in Southwest China. Finally, 10 debris flow gullies on the upstream of the Dadu River are analyzed to verify the reliability of the proposed model. The results show that the accuracy of the statistical model is 90 %.

scholarly journals Numerical simulation of debris flows

2000 ◽  
Vol 37 (1) ◽  
pp. 146-160 ◽  
Author(s):  
H Chen ◽  
C F Lee
Keyword(s):  
Hong Kong ◽  
Debris Flow ◽  
Numerical Solution ◽  
Dynamic Model ◽  
Debris Flows ◽  
Soil Column ◽  
Three Dimensional ◽  
Landslide Risk ◽  
Lumped Mass ◽  
Runout Distance

A key requirement in the assessment of landslide risk in such densely populated urban areas as Hong Kong consists of the prediction of potential runout distance or the extent of the subsequent debris flow. This paper presents a three-dimensional dynamic model of unsteady gravity-driven debris flow. The Lagrangian Galerkin finite element method is used to determine the nodal velocity and depth of soil column elements within the sliding mass, with the momentum and mass conservation mathematically closed within the soil column elements. The numerical solution also features a lumped mass matrix and a volume-weighted procedure. The method of least squares approximation plays a smoothing role which enhances stability and efficiency of the numerical solution scheme. The nodal elevation during sliding is obtained via a dynamic bilinear interpolation of the elevation function for the base of the sliding mass. Furthermore, the accuracy, robustness, and generality of this method are validated by experimental results. Its application to the Shum Wan Road landslide and the Fei Tsui Road landslide, both of which occurred during a heavy rainstorm in Hong Kong on 13 August 1995 and involved fatalities, gives reasonable results in comparison to the field observations. A variety of rheological constitutive relationships have already been coded in the present program to provide flexibility and adaptability in practical applications.Key words: debris flows, three-dimensional dynamic model, runout distance.

scholarly journals Classification and susceptibility assessment of debris flow based on a semi-quantitative method combination of the fuzzy <i>C</i>-means algorithm, factor analysis and efficacy coefficient

2020 ◽  
Vol 20 (5) ◽  
pp. 1287-1304 ◽  
Author(s):  
Zhu Liang ◽  
Changming Wang ◽  
Songling Han ◽  
Kaleem Ullah Jan Khan ◽  
Yiao Liu
Keyword(s):  
Factor Analysis ◽  
Debris Flow ◽  
Human Activity ◽  
Land Use Planning ◽  
Debris Flows ◽  
Risk Mitigation ◽  
Field Investigation ◽  
Matter Source ◽  
Susceptibility Analysis ◽  
Major Factors

Abstract. The existence of debris flows not only destroys the facilities but also seriously threatens human lives, especially in scenic areas. Therefore, the classification and susceptibility analysis of debris flow are particularly important. In this paper, 21 debris flow catchments located in Huangsongyu Township, Pinggu District, Beijing, China, were investigated. Besides field investigation, a geographic information system, a global positioning system and remote-sensing technology were applied to determine the characteristics of debris flows. This article introduced a clustering validity index to determine the clustering number, and the fuzzy C-means algorithm and factor analysis method were combined to classify 21 debris flow catchments in the study area. The results were divided into four types: debris flow closely related to scale–topography–human activity, topography–human activity–matter source, scale–matter source–geology and topography–scale–matter source–human activity. Nine major factors screened from the classification result were selected for susceptibility analysis, using both the efficacy coefficient method and the combination weighting. Susceptibility results showed that the susceptibility levels of 2 debris flow catchments were high, 6 were moderate and 13 were low. The assessment results were consistent with the field investigation. Finally, a comprehensive assessment including classification and susceptibility evaluation of debris flow was obtained, which was useful for risk mitigation and land use planning in the study area and provided a reference for the research on related issues in other areas.

scholarly journals Debris flow characteristics and relationships in the Central Spanish Pyrenees

2003 ◽  
Vol 3 (6) ◽  
pp. 683-691 ◽  
Author(s):  
A. Lorente ◽  
S. Beguería ◽  
J. C. Bathurst ◽  
J. M. García-Ruiz
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Flow Characteristics ◽  
Spatial Prediction ◽  
Runout Distance ◽  
Building Models ◽  
Spanish Pyrenees ◽  
Physically Based ◽  
Order Of Magnitude ◽  
The Difference

Abstract. Unconfined debris flows (i.e. not in incised channels) are one of the most active geomorphic processes in mountainous areas. Since they can threaten settlements and infrastructure, statistical and physically based procedures have been developed to assess the potential for landslide erosion. In this study, information on debris flow characteristics was obtained in the field to define the debris flow runout distance and to establish relationships between debris flow parameters. Such relationships are needed for building models which allow us to improve the spatial prediction of debris flow hazards. In general, unconfined debris flows triggered in the Flysch Sector of the Central Spanish Pyrenees are of the same order of magnitude as others reported in the literature. The deposition of sediment started at 17.8°, and the runout distance represented 60% of the difference in height between the head of the landslide and the point at which deposition started. The runout distance was relatively well correlated with the volume of sediment.

scholarly journals Susceptibility Analysis of the Mt. Umyeon Landslide Area Using a Physical Slope Model and Probabilistic Method

2020 ◽  
Vol 12 (16) ◽  
pp. 2663 ◽  
Author(s):  
Sunmin Lee ◽  
Jungyoon Jang ◽  
Yunjee Kim ◽  
Namwook Cho ◽  
Moung-Jin Lee
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Roc Curve ◽  
Landslide Susceptibility ◽  
Prediction Accuracy ◽  
Probabilistic Method ◽  
Landslide Prediction ◽  
Deterministic Analysis ◽  
Susceptibility Analysis ◽  
Prediction Rate

Every year, many countries carry out landslide susceptibility analyses to establish and manage countermeasures and reduce the damage caused by landslides. Because increases in the areas of landslides lead to new landslides, there is a growing need for landslide prediction to reduce such damage. Among the various methods for landslide susceptibility analysis, statistical methods require information about the landslide occurrence point. Meanwhile, analysis based on physical slope models can estimate stability by considering the slope characteristics, which can be applied based on information about the locations of landslides. Therefore, in this study, a probabilistic method based on a physical slope model was developed to analyze landslide susceptibility. To this end, an infinite slope model was used as the physical slope model, and Monte Carlo simulation was applied based on landslide inventory including landslide locations, elevation, slope gradient, specific catchment area (SCA), soil thickness, unit weight, cohesion, friction angle, hydraulic conductivity, and rainfall intensity; deterministic analysis was also performed for the comparison. The Mt. Umyeon area, a representative case for urban landslides in South Korea where large scale human damage occurred in 2011, was selected for a case study. The landslide prediction rate and receiver operating characteristic (ROC) curve were used to estimate the prediction accuracy so that we could compare our approach to the deterministic analysis. The landslide prediction rate of the deterministic analysis was 81.55%; in the case of the Monte Carlo simulation, when the failure probabilities were set to 1%, 5%, and 10%, the landslide prediction rates were 95.15%, 91.26%, and 90.29%, respectively, which were higher than the rate of the deterministic analysis. Finally, according to the area under the curve of the ROC curve, the prediction accuracy of the probabilistic model was 73.32%, likely due to the variability and uncertainty in the input variables.

Runout modeling based debris flow risk assessment: a case study from Garhwal Himalaya, India

2020 ◽  
Author(s):  
Rajesh Kumar Dash ◽  
Debi Prasanna Kanungo
Keyword(s):  
Risk Assessment ◽  
Debris Flow ◽  
Debris Flows ◽  
Back Analysis ◽  
Source Area ◽  
Quantitative Information ◽  
Source Zone ◽  
Garhwal Himalayas ◽  
Model Input ◽  
Input Parameters

&lt;p&gt;Debris flows are one of the most frequently occurring and destructive hazards in Indian Himalayas which are often initiated by rainfall. &amp;#160;To minimize the losses due to the destructive power of the debris flows, demarcation of debris flow risk zones is an effective practice for risk reduction. In the present study, site specific debris flow risk assessment has been carried out based upon runout behaviour modeling. Tangni debris flow is an active debris flow in the Chamoli district of Garhwal Himalayas, India which is responsible for disrupting the traffic by blocking the road for days. This debris flow is repetitive in nature and occurs many a times every year in the monsoon during the months between June to September. The Tangni debris flow is categorized as a hill slope debris flow and the failure is considered as a block failure. Runout modeling of Tangni debris flow has been carried out using a Voellmy approach based continuum model. Quantitative information on debris flow intensity parameters such as flow velocity, height and pressure was obtained from the numerical simulation. The calibration of model input parameters was done by back analysis of an event from a particular source area that took place in 2013. Depending upon the amount of materials present in different source areas in the entire source zone and using the calibrated model input parameters, several simulations were performed to assess the flow behaviour of at different possible scenarios. Thus, Tangni debris flow risk assessment has been carried out based on its runout effect modeling. This study revealed that there may be a possibility of damming of river as well as blocking of the National Highway which are located at the downstream of the debris flow.&lt;/p&gt;&lt;p&gt;Key words:&amp;#160; Debris flow, Risk assessment, Runout modeling, Garhwal Himalayas, Voellmy model&lt;/p&gt;

scholarly journals Risk Identification of Lijiadagou Landslide and Debris Flow Hazards Chain in Yong'an Town, Fengjie County of Chongqing City

2021 ◽  
pp. 1-12
Author(s):  
Q. H. Song ◽  
S. C. Ren ◽  
X. L. LI ◽  
B. L. Chen ◽  
K. Li ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Social Impact ◽  
Source Area ◽  
Economic Loss ◽  
Soil Mass ◽  
Mechanical Analysis ◽  
Field Investigation ◽  
Risk Identification ◽  
Alternate Control

Lijiadagou landslide and debris flow hazards chain in Yong’an Town of Fengjie county is one of the representative geohazards. By using satellite remote sensing technology, field investigation and observation, survey and analysis, mechanical analysis and other technical means, this paper makes qualitative or semi quantitative analysis on the hazard environment, instability probability, vulnerability analysis of elements at risk, risk loss, etc. The risk factors of Lijiadagou landslide and debris flow were identified. The conclusion shows that the unique landform and climate of Lijiadagou lay a foundation for the occurrence of multiple debris flows in the history. Under the alternate control of multiple factors such as the nature of the rock and soil mass, the stratum structure that controls the sliding, the complex geomorphic environment, continuous heavy rainfall and the rise and fall of the water level, there are high risks of landslides and debris flows, threatening about  6,000 residents in the middle and front range of Lijiadagou. The risk economic loss of hazards is about 80 million yuan, and will cause serious social impact. It is urgent to strengthen monitoring and early warning, and at the same time take targeted measures against the landslide source  area to cut off the hazards chain from the source, so as to achieve a multiplier effect with half the effort.

scholarly journals The ability of tree stems to intercept debris flows in forested fan areas: A laboratory modelling study

2018 ◽  
Vol 49 (1) ◽  
pp. 42-51
Author(s):  
Francesco Bettella ◽  
Tamara Michelini ◽  
Vincenzo D'Agostino ◽  
Gian Battista Bischetti
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Sediment Concentration ◽  
Damage Potential ◽  
Protective Function ◽  
Runout Distance ◽  
Depositional Processes ◽  
General Terms ◽  
Flow Motion ◽  
Key Factor

Debris flows are one of the most common geomorphic processes in steep mountainous areas. The control of their propagation on alluvial fans is fundamental; valley bottoms are usually characterised by high damage potential because they contain concentrations of inhabitants and infrastructure. It is well known that forests have a protective function in that they reduce the triggering of debris flows, as well as hinder their motion and promote deposition, but a quantitative assessment of these effects is still lacking. Using laboratory experiments that simulate debris-flow depositional processes, this research investigated the ability of forests to reduce debris-flow runout and depositional area. The experiments considered two different forest types, high forests and coppice forests, and four volumetric concentrations of sediment (0.50, 0.55, 0.60, and 0.65). The results confirmed that the sediment concentration of the flow is a key factor in determining the geometry of the deposits. On the other hand, forests can reduce debris-flow runout distance and, in general terms, affect the characteristics of their deposits. The results showed that vegetation appear to reduce debris-flow motion especially when the debris-flow kinematic load at the fan apex is low. About the sediment concentration of the mixture, high forest did not exhibit a clear behaviour while coppice forest appears to promote significant deposition at all of the tested concentrations, and this effect increases with the solid concentration (reductions in runout between approximately 20% and 30% at CV=0.50 and CV=0.65, respectively, were observed). Due to their higher tree density, in fact, coppice forests seem to have a better protective effect than the rigid trunks of high forest trees. For this last type of forest, a relationship between the H/L ratio, which represents energy dissipation, have been found and compared with the scenario without forest.

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