Suitability of Mono- and Two-Phase Modeling of Debris Flows for the Assessment of Granular Debris Flow Hazards: Insights from a Case Study

2015 ◽  
pp. 537-543 ◽  
Author(s):  
Cristiano Lanni ◽  
Bruno Mazzorana ◽  
Pierpaolo Macconi ◽  
Rudi Bertagnolli
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Two Phase

scholarly journals Estimation of flow velocity for a debris flow via the two-phase fluid model

2015 ◽  
Vol 22 (1) ◽  
pp. 109-116 ◽  
Author(s):  
S. Guo ◽  
P. Xu ◽  
Z. Zheng ◽  
Y. Gao
Keyword(s):  
Debris Flow ◽  
Real World ◽  
Empirical Formula ◽  
Debris Flows ◽  
Fluid Model ◽  
Two Phase ◽  
Liquid Phases ◽  
Two Phases ◽  
Phase Fluid ◽  
Steady Velocity

Abstract. The two-phase fluid model is applied in this study to calculate the steady velocity of a debris flow along a channel bed. By using the momentum equations of the solid and liquid phases in the debris flow together with an empirical formula to describe the interaction between two phases, the steady velocities of the solid and liquid phases are obtained theoretically. The comparison of those velocities obtained by the proposed method with the observed velocities of two real-world debris flows shows that the proposed method can estimate the velocity for a debris flow.

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 Protecting highway bridges against debris flows using lateral berms: a case study of the 2008 and 2011 Cheyang debris flow events, China

2017 ◽  
Vol 9 (1) ◽  
pp. 196-210 ◽  
Author(s):  
Fei Qiu ◽  
Jianling Huang ◽  
Yange Li ◽  
Zheng Han ◽  
Weidong Wang ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Highway Bridges

scholarly journals Evaluation of Rainfall-Triggered Debris Flows under the Impact of Extreme Events: A Chenyulan Watershed Case Study, Taiwan

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2201
Author(s):  
Jinn-Chyi Chen ◽  
Wen-Shun Huang
Keyword(s):  
Debris Flow ◽  
Extreme Events ◽  
Debris Flows ◽  
Extreme Rainfall ◽  
Extreme Rainfall Event ◽  
Extreme Rainfall Events ◽  
Hourly Rainfall ◽  
Central Taiwan ◽  
The Impact

This study examined the conditions that lead to debris flows, and their association with the rainfall return period (T) and the probability of debris flow occurrence (P) in the Chenyulan watershed, central Taiwan. Several extreme events have occurred in the Chenyulan watershed in the past, including the Chi-Chi earthquake and extreme rainfall events. The T for three rainfall indexes (i.e., the maximum hourly rainfall depth (Im), the maximum 24-h rainfall amount (Rd), and RI (RI = Im× Rd)) were analyzed, and the T associated with the triggering of debris flows is presented. The P–T relationship can be determined using three indexes, Im, Rd, and RI; how it is affected and unaffected by extreme events was developed. Models for evaluating P using the three rainfall indexes were proposed and used to evaluate P between 2009 and 2020 (i.e., after the extreme rainfall event of Typhoon Morakot in 2009). The results of this study showed that the P‒T relationship, using the RI or Rd index, was reasonable for predicting the probability of debris flow occurrence.

scholarly journals Hydrometeorological Triggering of Periglacial Debris Flows Using a Bayesian Approach: A Case Study of the Hailuogou Gully Region, China

2021 ◽  
Author(s):  
Zheng Wang ◽  
Ningsheng Chen ◽  
Guisheng Hu ◽  
Yong Zhang ◽  
Genxu Wang ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
High Elevation ◽  
Tibet Plateau ◽  
Hydrological Characteristics ◽  
Effects Of Temperature ◽  
Qinghai Tibet Plateau ◽  
Hydrometeorological Conditions ◽  
Debris Flow Initiation

Abstract Mount Gonggais located in the east of the Qinghai–Tibet Plateau; many debris flows have occurred in small basins with a small glacier cover or snow cover in this area. The hydrometeorological conditions that caused debris flows in this region are complex, making forecasting and early warning difficult. Previous studies for these small-glacial-covered basins have primarily considered rainfall as the only inducing factor of debris flows, and often the effects of temperature are neglected. Thus, we carried out a probabilistic analysis of variables derived from hydrometeorological factors for the Mount Gongga region, Sichuan, China, where debris flows were recorded on 14 days between 1988 and 2019. By analyzing hydrological characteristics when debris flows occurred, three distinct dominant trigger types could be identified. The results show that 7 (50%) of the observed debris flow events during the study period, high-intensity rainfall was the dominant trigger, snowmelt by high temperature was identified as the dominant trigger for 2 (14%). Furthermore, 5 (36%) debris flow events could be attributed to the combined effects of long-lasting (or short-medium) rainfall and sustained higher temperatures. We find that the differences between the trigger types are statistically significant, and a susceptibility prediction differentiating between trigger types can outperform simple rainfall-only situations. This study contributes to an improved understanding of the hydrometeorological impact on debris flow initiation in high elevation watersheds.

scholarly journals Application of simulation technique on debris flow hazard zone delineation: a case study in the Daniao tribe, Eastern Taiwan

2011 ◽  
Vol 11 (11) ◽  
pp. 3053-3062 ◽  
Author(s):  
M. P. Tsai ◽  
Y. C. Hsu ◽  
H. C. Li ◽  
H. M. Shu ◽  
K. F. Liu
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Sensitivity Factor ◽  
Original Design ◽  
Initial Volume ◽  
Front Position ◽  
Landslides And Debris Flows ◽  
Numerical Program

Abstract. Typhoon Morakot struck Taiwan in August 2009 and induced considerable disasters, including large-scale landslides and debris flows. One of these debris flows was experienced by the Daniao tribe in Taitung, Eastern Taiwan. The volume was in excess of 500 000 m3, which was substantially larger than the original design mitigation capacity. This study considered large-scale debris flow simulations in various volumes at the same area by using the DEBRIS-2D numerical program. The program uses the generalized Julien and Lan (1991) rheological model to simulate debris flows. In this paper, the sensitivity factor considered on the debris flow spreading is the amount of the debris flow initial volume. These simulated results in various amounts of debris flow initial volume demonstrated that maximal depths of debris flows were almost deposited in the same area, and also revealed that a 20% variation in estimating the amount of total volume at this particular site results in a 2.75% variation on the final front position. Because of the limited watershed terrain, the hazard zones of debris flows were not expanded. Therefore, the amount of the debris flow initial volume was not sensitive.

The geomorphic impact of large landslides: A case-study of the actively moving Alpine Gardens Landslide, Fox Glacier Valley, West Coast, New Zealand.

2020 ◽  
Author(s):  
Saskia de Vilder ◽  
Chris Massey ◽  
Garth Archibald ◽  
Regine Morgenstern
Keyword(s):  
New Zealand ◽  
Debris Flow ◽  
West Coast ◽  
Debris Flows ◽  
Sediment Flux ◽  
Valley Floor ◽  
Aerial Imagery ◽  
Glacier Valley ◽  
Flow Activity

<p>Large landslides can result in significant geomorphic impacts to fluvial systems, via increased sediment input and subsequent changes to channel behaviour. We present a case-study of the actively moving  ̴65 M m³ Alpine Gardens Landslide in the Fox Glacier Valley, West Coast, New Zealand, to analyse the ongoing geomorphic impacts within the valley floor. Debris flows, sourced from the toe of the landslide, travel down Mill’s Creek and deposit sediment on the debris fan at its confluence with the Fox River. This debris flow activity and associated changes in sediment flux and fluvial behaviour have resulted in re-occurring damage to, and current closure of roads and tracks within the Fox Glacier Valley floor, impacting access to the Westland Tai Poutini National Park, the Fox Glacier, associated tourism, and the Fox Glacier township economy.</p><p>Initial movement of the Alpine Gardens landslide was detected in 2015, with aerial imagery analysis between March 2017 and June 2018 indicating that the landslide may be accelerating. This acceleration may potentially result in increased debris flow activity within the landslide complex and sediment flux into the Fox River. To monitor and understand the controls on movement rate, we installed a continuous GPS monitoring station along with rainfall gauges on the landslide in February 2019. On average, the landslide moves at a rate of 0.12 m/day ± 0.13 m/day, however this rate of movement of the landslide is closely correlated to and fluctuates with rainfall. Significant accelerations of 0.5 m/day have occurred after heavy rainfall, with these rainfall events also resulting in large debris flows.</p><p>We document and investigate the geomorphic impact of the Alpine Gardens landslide on the Mill’s Creek debris fan and Fox Glacier Valley floor via terrestrial laser scanning, airborne LiDAR, UAV surveys and aerial imagery. From this, we derive a time-series of nine surface change models to document the sediment flux within the Alpine Gardens Landslide and Mill’s Creek debris fan complex. Our initial results reveal that between March 2017 and June 2019, approximately 14.7 M m³ was eroded from the landslide, of which 3.7 M m³ was deposited directly on the debris fan. A further 9.6 M m³ has been transported downstream into the fluvial system. Upstream aggradation has also occurred, with 1.1 M m³ deposited in the river valley immediately upstream of the debris fan between June 2018 and June 2019. Continued monitoring of the Alpine Gardens Landslide and volumetric changes of the landslide complex allows us to understand the controls on the movement and sediment flux within the landslide and the geomorphic impact of large actively moving landslides on the valley floor, particularly within alpine and glacial environments. </p>

IMPACT OF EARTHQUAKE ON DEBRIS FLOWS — A CASE STUDY ON THE WENCHUAN EARTHQUAKE

2011 ◽  
Vol 05 (05) ◽  
pp. 493-508 ◽  
Author(s):  
NING-SHENG CHEN ◽  
GUI-SHENG HU ◽  
MING-FENG DENG ◽  
WEI ZHOU ◽  
CHENG-LIN YANG ◽  
...  
Keyword(s):  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Key Factors ◽  
Land Form ◽  
Earthquakes In China ◽  
The Impact ◽  
Debris Flow Initiation ◽  
Stable Stage

This paper describes a study about the impact of earthquakes on debris flows with a focus on the Great Wenchuan Earthquake 2008 in China. The land form, precipitation, and source material are the three key factors for debris flow initiation in the Wenchuan surrounding area. Classifications and examples of four types of debris flow initiation triggering (gully triggering, slope triggering, liquefaction triggering, and gully erosion triggering) have been presented. The initiation mechanisms are attributed to hydraulic and geomechanical aspects. The actual debris flow cases linked with the Great Wenchuan Earthquake and other earthquakes in China have been used to illustrate the increased magnitudes of debris flows due to a large amount of loose materials created by the seismic actions. The critical precipitation for debris flows is reduced by the earthquake. It is predicted that the impact of the Great Wenchuan Earthquake on the local debris flows would be significant in the next 5–6 years, and much less in the following years (up to 20 years). Finally, the debris flow system will reach a relative stable stage. This prediction is based on the historical observations at other earthquake areas and the qualitative analysis on debris flow initiation mechanisms.

scholarly journals A two-phase model for numerical simulation of debris flows

2014 ◽  
Vol 2 (3) ◽  
pp. 2151-2183 ◽  
Author(s):  
S. He ◽  
W. Liu ◽  
C. Ouyang ◽  
X. Li
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Volume Fraction ◽  
Solid Phase ◽  
Fluid Phase ◽  
Viscous Drag ◽  
Finite Volume Scheme ◽  
Viscous Stress ◽  
Two Phase ◽  
One Dimensional

Abstract. Debris flows are multiphase, gravity-driven flows consisting of randomly dispersed interacting phases. The interaction between the solid phase and liquid phase plays a significant role on debris flow motion. This paper presents a new two-phase debris flow model based on the shallow water assumption and depth-average integration. The model employs the Mohr–Coulomb plasticity for the solid stress, and the fluid stress is modeled as a Newtonian viscous stress. The interfacial momentum transfer includes viscous drag, buoyancy and interaction force between solid phase and fluid phase. We solve numerically the one-dimensional model equations by a high-resolution finite volume scheme based on a Roe-type Riemann solver. The model and the numerical method are validated by using one-dimensional dam-break problem. The influences of volume fraction on the motion of debris flow are discussed and comparison between the present model and Pitman's model is presented. Results of numerical experiments demonstrate that viscous stress of fluid phase has significant effect in the process of movement of debris flow and volume fraction of solid phase significantly affects the debris flow dynamics.

scholarly journals Estimation of flow velocity for a debris flow via the two-phase fluid model

2014 ◽  
Vol 1 (1) ◽  
pp. 999-1021
Author(s):  
S. Guo ◽  
P. Xu ◽  
Z. Zheng ◽  
Y. Gao
Keyword(s):  
Debris Flow ◽  
Real World ◽  
Empirical Formula ◽  
Debris Flows ◽  
Fluid Model ◽  
Two Phase ◽  
Liquid Phases ◽  
Two Phases ◽  
Phase Fluid ◽  
Steady Velocity

Abstract. The two-phase fluid model is applied in this study to calculate the steady velocity of a debris flow along a channel bed. By using the momentum equations of the solid and liquid phases in the debris flow together with an empirical formula to describe the interaction between two phases, the steady velocities of the solid and liquid phases are obtained theoretically. The comparison of those velocities obtained by the proposed method with the observed velocities of two real-world debris flows shows that the proposed method can estimate accurately the velocity for a debris flow.

Sign in / Sign up

Export Citation Format

Share Document