Effects of Soil Porosity on Slope Stability and Debris Flow Runout at a Weathered Granitic Hillslope

2006 ◽  
Vol 5 (1) ◽  
pp. 283-295 ◽  
Author(s):  
Muhammad Mukhlisin ◽  
Ken'ichirou Kosugi ◽  
Yoshifumi Satofuka ◽  
Takahisa Mizuyama
Keyword(s):  
Slope Stability ◽  
Debris Flow ◽  
Soil Porosity

scholarly journals Landslide and debris flow susceptibility zonation using TRIGRS for the 2011 Seoul landslide event

2013 ◽  
Vol 1 (3) ◽  
pp. 2547-2587 ◽  
Author(s):  
D. W. Park ◽  
N. V. Nikhil ◽  
S. R. Lee
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Debris Flow ◽  
Slope Stability Analysis ◽  
Flow Paths ◽  
Infinite Slope ◽  
Erosion Rates ◽  
Landslide Event ◽  
Physically Based ◽  
Pore Pressure Response

Abstract. This paper presents the results from application of a regional, physically-based stability model: Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis (TRIGRS) for a catchment on Woomyeon Mountain, Seoul, Korea. This model couples an infinite-slope stability analysis with a one-dimensional analytical solution to predict the transient pore pressure response to the infiltration of rainfall. TRIGRS also adopts the Geographic Information Systems (GIS) framework for determining the whole behaviour of a slope. In this paper, we suggest an index for evaluating the results produced by the model. Particular attention is devoted to the prediction of routes of debris flow, using a runoff module. In this context, the paper compares observed landslide and debris flow events with those predicted by the TRIGRS model. The TRIGRS model, originally developed to predict shallow landslides, has been extended in this study for application to debris flows. The results predicted by the TRIGRS model are presented as safety factor (FS) maps corresponding to transient rainfall events, and in terms of debris flow paths using methods proposed by several researchers in hydrology. In order to quantify the accuracy of the model, we proposed an index called LRclass (landslide ratio for each predicted FS class). The LRclass index is mainly applied in regions where the landslide scar area is not well defined (or is unknown), in order to avoid over-estimation of the model results. The use of the TRIGRS routing module was proposed to predict the paths of debris flow, especially in areas where the rheological properties and erosion rates of the materials are difficult to obtain. Although an improvement in accuracy is needed, this module is very useful for preliminary spatiotemporal assessment over wide areas. In summary, the TRIGRS model is a powerful tool of use to decision makers for susceptibility mapping, particularly when linked with various advanced applications using GIS spatial functions.

scholarly journals Landslides and slope stability evaluation in the historical town of Kruja, Albania

2013 ◽  
Vol 1 (4) ◽  
pp. 3263-3304
Author(s):  
Y. Muceku ◽  
O. Korini
Keyword(s):  
Slope Stability ◽  
Debris Flow ◽  
Urban Area ◽  
Urban Areas ◽  
Geological Mapping ◽  
Stability Evaluation ◽  
Engineering Geological Mapping ◽  
The Past ◽  
Field Works ◽  
Cultural Monuments

Abstract. This paper describes the landslides and slope stability evaluation in the urban area of Kruja town, Albania. Kruja is a~historical and heritage center, due to the existence of many important cultural monuments including Skanderbeg castle and Bazaar square etc. The urban area of Kruja town has been affected from the Landslides effects, in the past and also present. From this phenomenon many engineering objects such as buildings, roads etc. are damaged and demolished. From the engineering geological mapping at scale 1 : 5000 it is observed that many active landslides have dramatically increased in activity after 1980s. The landslide types found in the studied area are earth slides, debris flow, as well as rock fall and rock rolling. Also, from field works and laboratory analysis, the slope stability of whole urban areas has been determined; for this purpose the studied zone is divided into the stable and unstable areas, which helps to better understand the mass movement's activity as one of the most harmful hazards of the geodynamics' phenomena.

scholarly journals Landslide and debris flow susceptibility zonation using TRIGRS for the 2011 Seoul landslide event

2013 ◽  
Vol 13 (11) ◽  
pp. 2833-2849 ◽  
Author(s):  
D. W. Park ◽  
N. V. Nikhil ◽  
S. R. Lee
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Debris Flow ◽  
Slope Stability Analysis ◽  
Flow Paths ◽  
Erosion Rates ◽  
Landslide Event ◽  
Physically Based ◽  
Spatio Temporal ◽  
Pore Pressure Response

Abstract. This paper presents the results from the application of a regional, physically based stability model: Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis (TRIGRS) for a region on Woomyeon Mountain, Seoul, South Korea. This model couples an infinite-slope stability analysis with a one-dimensional analytical solution to predict the transient pore pressure response to the infiltration of rainfall. TRIGRS also adopts the geographic information system (GIS) framework for determining the whole behaviour of a slope. In this paper, we suggest an index for evaluating the results produced by the model. Particular attention is devoted to the prediction of routes of debris flow, using a runoff module. In this context, the paper compares observed landslide and debris flow events with those predicted by the TRIGRS model. The TRIGRS model, originally developed to predict shallow landslides, has been extended in this study for application to debris flows. The results predicted by the TRIGRS model are presented as safety factor (FS) maps corresponding to transient rainfall events, and in terms of debris flow paths using methods proposed by several researchers in hydrology. In order to quantify the effectiveness of the model, we proposed an index called LRclass (landslide ratio for each predicted FS class). The LRclass index is mainly applied in regions where the landslide scar area is not well defined (or is unknown), in order to avoid overestimation of the model results. The use of the TRIGRS routing module was proposed to predict the paths of debris flow, especially in areas where the rheological properties and erosion rates of the materials are difficult to obtain. Although an improvement in accuracy is needed, this module is very useful for preliminary spatio-temporal assessment over wide areas. In summary, the TRIGRS model is a powerful tool of use to decision makers for susceptibility mapping, particularly when linked with various advanced applications using GIS spatial functions.

scholarly journals Coupled prediction of flood response and debris flow initiation during warm and cold season events in the Southern Appalachians, USA

2013 ◽  
Vol 10 (7) ◽  
pp. 8365-8419 ◽  
Author(s):  
J. Tao ◽  
A. P. Barros
Keyword(s):  
Slope Stability ◽  
Debris Flow ◽  
Debris Flows ◽  
Warning System ◽  
Cold Season ◽  
Southern Appalachians ◽  
Winter Storm ◽  
Headwater Catchments ◽  
Flood Response ◽  
Debris Flow Initiation

Abstract. Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas warm season events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold season events. Instead, there is a relationship between large (cumulative) rainfall events independently of season, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. The first objective of this study is to investigate this hypothesis. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface-groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations, availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions, and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions necessary for the initiation of slope instability, and should therefore be considered explicitly in landslide hazard assessments. Moreover, the relationships between slope stability and interflow are strongly modulated by the topography and catchment specific geomorphologic features that determine subsurface flow convergence zones. The three case-studies demonstrate the value of coupled prediction of flood response and debris flow initiation potential in the context of developing a regional hazard warning system.

Regional and detailed multi-hazard assessment of debris-flow processes in the Colombian Andes

2021 ◽  
Author(s):  
Federico Gómez Cardona ◽  
Edier Aristizábal Giraldo ◽  
Maria Isabel Arango ◽  
Martin Mergili
Keyword(s):  
Slope Stability ◽  
Debris Flow ◽  
Hazard Assessment ◽  
Flash Flood ◽  
Fluid Dynamic ◽  
Local Scale ◽  
Catchment Scale ◽  
Colombian Andes ◽  
Flow Processes ◽  
Physically Based

<p>Debris-flow processes are highly destructive phenomena that endanger life and infrastructure located in mountainous areas. The Colombian Andes are especially susceptible to this type of processes. Disaster databases include 1,387 channelized debris flow, debris flood, and flash flood records between 1921 and 2020, causing 3,332 deaths and affecting 1,152,613 people. These statistics show the importance of carrying out a regional debris flow hazard assessment to prioritize resources and actions to reduce risk.</p><p>One of the main challenges when evaluating debris-flow processes hazard is their multi-hazard nature: they are understood as part of a concatenated phenomenon at catchment scale, including cascading effects of landslides, flash floods, debris floods and channelised debris flows. In this study, a multi-hazard approach was implemented to assess debris-flow processes susceptibility and hazard on both regional and local scale, combining statistical and physically based models in combination with geomorphological observations.</p><p>The study area is located in the central Colombia Andes, with an extension of 63,612 km<sup>2</sup> where 3,039 catchments were analysed for their debris flow-processes susceptibility, using machine learning methods based on morphometric parameters. This analysis was joined with a physically-based slope stability model to estimate potential sediment volumes that might be supplied by intense rainstorms. By combining susceptibility, slope stability, and soil type at the catchment scale, it was possible to understand the magnitude of the potential of different debris-flow processes. Susceptibility analysis allowed to differentiate the catchments into alluvial and torrential and their magnitude level was categorized based on the volume of unstable soil to find hazard and then, used to select critical catchments for a more detailed scale.</p><p>A detailed hazard analysis was carried out for those selected areas through hydrological and hydraulic software, along with fluid-dynamic mass routing models. These methodologies were used with a sub- metric resolution and provide detailed information such as flow height, speed, and pressure to categorize more accurate hazard levels, always framed on the torrential geomorphology units.</p><p>Traditional hydraulic and hydrological models were insufficient to provide accurate heights and extents of debris-flow processes since they do not consider their multi-hazard nature nor the volume of sediments from landslides and channel erosion that are added to the flow. As a result, the extent of the flow was smaller than the observed morphological features. The fluid dynamic model r.avaflow considers the rheologic change and fitted better to the type of events. The model was used to simulate different sediment concentrations and flow types. The model results were complemented with the different torrential units mapped through fieldwork. This way, it was possible to establish the events’ maximum potential extent linked to their return periods.</p><p>This multi-hazard and multi-scale methodology is a useful tool for stakeholders to prioritize and improve urban planning. It grants a perspective from regional to local scale, can be adapted to fit into specific environments and contexts.</p>

scholarly journals Coupled prediction of flood response and debris flow initiation during warm- and cold-season events in the Southern Appalachians, USA

2014 ◽  
Vol 18 (1) ◽  
pp. 367-388 ◽  
Author(s):  
J. Tao ◽  
A. P. Barros
Keyword(s):  
Slope Stability ◽  
Debris Flow ◽  
Debris Flows ◽  
Warning System ◽  
Cold Season ◽  
Southern Appalachians ◽  
Winter Storm ◽  
Headwater Catchments ◽  
Flood Response ◽  
Debris Flow Initiation

Abstract. Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas warm-season events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold-season events. Instead, there is a relationship between large (cumulative) rainfall events independently of season, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. We further hypothesize that the transient mass fluxes associated with the temporal-spatial dynamics of interflow govern the timing of shallow landslide initiation, and subsequent debris flow mobilization. The first objective of this study is to investigate this relationship. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface–groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations; availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions; and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions necessary for the initiation of slope instability, and should therefore be considered explicitly in landslide hazard assessments. Moreover, the relationships between slope stability and interflow are strongly modulated by the topography and catchment-specific geomorphologic features that determine subsurface flow convergence zones. The three case studies demonstrate the value of coupled prediction of flood response and debris flow initiation potential in the context of developing a regional hazard warning system.

scholarly journals Slope Stability and Development of Debris Flow Deposit in the Ulleung Basin, East Sea

2017 ◽  
Vol 50 (2) ◽  
pp. 129-143
Author(s):  
Sun-Jong Lee ◽  
Jeong-Min Lee ◽  
Dong-Geun Yoo ◽  
Go-Eun Lee ◽  
Soo-Chul Park
Keyword(s):  
Slope Stability ◽  
Debris Flow ◽  
East Sea ◽  
Ulleung Basin ◽  
Debris Flow Deposit ◽  
Flow Deposit

scholarly journals The Application of a Three-Dimensional Deterministic Model in the Study of Debris Flow Prediction Based on the Rainfall-Unstable Soil Coupling Mechanism

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 99 ◽  
Author(s):  
Shuangshuang Qiao ◽  
Shengwu Qin ◽  
Junjun Chen ◽  
Xiuyu Hu ◽  
Zhongjun Ma
Keyword(s):  
Slope Stability ◽  
Debris Flow ◽  
Debris Flows ◽  
Deterministic Model ◽  
Regional Scale ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Coupling Mechanism ◽  
Forecasting Methods ◽  
Forecasting Method

As debris flow is one of the most destructive natural disasters in many parts of the world, the assessment and management of future debris flows with proper forecasting methods are crucial for the safety of life and property. So increasing attention has been paid to the forecasting methods on debris flows. A debris flow forecasting method based on the rainfall-unstable soil coupling mechanism (R-USCM) is presented in the current study. This method is based on the debris flow formation mechanism. The density of sediment is introduced as an evaluation index to determine the susceptibility of debris flow occurrence. The forecasting method includes two phases: (1) rainfall and soil coupling and (2) runoff and unstable soil coupling. Scoops3D, a three-dimensional (3D) model for analyzing slope stability, was introduced into the debris flow forecasting method. In order to test the forecasting accuracy of this method, Jiaohe County was selected as a research area, and the serious debris flow disasters attributed to strong rainfall on 20 July 2017 were taken as the research case. By comparing the forecasting results with the debris flow distribution map for Jiaohe County, the method based on the R-USCM is feasible for forecasting debris flows at the regional scale. The application of the Scoops3D model can more reasonably analyze the slope stability than the traditional two dimensional (2D) method and improve the forecasting ability of debris flows.

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