Using Numerical Model to Analyze Reduction of Debris Flows by the Installation Location of Check Dams

2017 ◽  
Vol 13 (4) ◽  
pp. 117-128
Author(s):  
Won Jun Tak ◽  
◽  
Kye Won Jun ◽  
Byung Sik Kim ◽  
Yong Ho Yoon ◽  
...  
Keyword(s):  
Numerical Model ◽  
Debris Flows ◽  
Check Dams

scholarly journals Elasto-plastic-adhesive DEM model for simulating hillslope debris flows: cross comparison with field experiments

2018 ◽  
Author(s):  
Adel Albaba ◽  
Massimiliano Schwarz ◽  
Corinna Wendeler ◽  
Bernard Loup ◽  
Luuk Dorren
Keyword(s):  
Numerical Model ◽  
Flow Velocity ◽  
Debris Flows ◽  
Field Experiments ◽  
Initial Conditions ◽  
Experimental Tests ◽  
Height Velocity ◽  
Model Parameters ◽  
Fine Content ◽  
Adhesive Model

Abstract. This paper presents a Discrete Element-based elasto-plastic-adhesive model which is adapted and tested for producing hillslope debris flows. The numerical model produces three phases of particle contacts: elastic, plastic and adhesion. The model capabilities of simulating different types of cohesive granular flows were tested with different ranges of flow velocities and heights. The basic model parameters, being the basal friction (ϕb) and normal restitution coefficient (ϵn), were calibrated using field experiments of hillslope debris flows impacting two sensors. Simulations of 50 m3 of material were carried out on a channelized surface that is 41 m long and 8 m wide. The calibration process was based on measurements of flow height, flow velocity and the pressure applied to a sensor. Results of the numerical model matched well those of the field data in terms of pressure and flow velocity while less agreement was observed for flow height. Those discrepancies in results were due in part to the deposition of material in the field test which are not reproducible in the model. A parametric study was conducted to further investigate that effect of model parameters and inclination angle on flow height, velocity and pressure. Results of best-fit model parameters against selected experimental tests suggested that a link might exist between the model parameters ϕb and ϵn and the initial conditions of the tested granular material (bulk density and water and fine contents). The good performance of the model against the full-scale field experiments encourages further investigation by conducting lab-scale experiments with detailed variation of water and fine content to better understand their link to the model's parameters.

Alternative approach for works controlling stony debris flows

2020 ◽  
Author(s):  
Carlo Gregoretti ◽  
Matteo Barbini ◽  
Martino Bernard ◽  
Mauro Boreggio
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
High Elevation ◽  
Valley Bottom ◽  
Check Dams ◽  
Retention Basin ◽  
Retention Basins ◽  
Solid Liquid ◽  
The Impact ◽  
The Village

<p>Many sites of the Dolomites are threatened by channelized debris flows: solid-liquid surges initiated by the entrainment of large quantities of sediments into the abundant runoff at the head of channel incised on fans, can dramatically increase their volume along the downstream routing. This is the case of the Rovina di Cancia site where solid-liquid surges forming in the upper part of the basin can increase their volume up and over 50000 m<sup>3</sup>, seriously impacting the downstream village of Borca di Cadore. The debris-flow channel ends just upstream the village that in the past was hit by four debris flows (three in the recent years) that caused victims and destructions. Control works built until now are not sufficient to protect the village from high magnitude debris flows and a definitive solution calls to be planned. Present works are a flat deposition area, 300 m downstream the initiation area, an open dam under construction downstream it, and  two retention basins at the end of the channel. Between the open dam and the upstream retention basin, there are the rest of eight check-dams made of gabions, built in the 60s and progressively damaged or destroyed by the debris flows occurred after their construction. This series of check-dams limited the entrainment of solid material and the occurrence of localized scours. The initial plan is the substitution of the check-dams with concrete structures and the widening of the dowsntream retention basin through the raising of high elevation embankment downstream it and the following demolition of the actual dyke. Finally, a channel crossing the village and national route on the valley bottom will deliver the fluid phase from the widened basin to the Boite river. All these control works have a very high cost for construction and maintenance and severely impact the village with the presence of a non-negligible residual risk. These drawbacks call for an alternative solution that is searched looking at to the morphology. Downstream of the open dam and on its right side, there is a deep impluvium that ends on a large grass sloping area. The novel solution requires the construction of a channel through the right high bank that deviates the debris flow into the impluvium. The impluvium, widened through the excavation of the surrounding slopes, is closed at the outlet by  an open dam. Downstream the open dam, a channel will lead to a retention basin, where most of storage volume is obtained from the excavation of the grass sloping area, limiting the elevation of the dykes At the end of this basin an open dam will deliver the debris-flow fluid part to a channel passing under the national route and joining the Boite river. Such a solution composed of a deviatory channel, two retention basins (the deep impluvium and that excavated on the sloping grass area) and the channels between and downstream them, has quite a lower costs of construction and maintenance, eliminating the impact on the village because occupying uninhabited areas without interrupting the main roads.</p>

Coupled Numerical Model CFD-DEM of Debris Flows Impact to Improve the Vulnerability Quantification of Structures

2021 ◽  
Author(s):  
Rime Chehade ◽  
Bastien Chevalier ◽  
Fabian Dedecker ◽  
Pierre Breul
Keyword(s):  
Numerical Model ◽  
Debris Flows ◽  
Coupled Numerical Model

scholarly journals A New Method to Evaluate the Combined Performance of Check Dams and Afforestation on Debris Flows Mitigation in a Dry-hot Valley

2021 ◽  
Author(s):  
Liqun Lyu ◽  
Mengzhen Xu ◽  
Guanyu Zhou ◽  
Zhaoyin Wang
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Yunnan Province ◽  
New Method ◽  
Energy Conditions ◽  
Vegetation Coverage ◽  
Economic Losses ◽  
Flow Volume ◽  
Jiangjia Gully ◽  
Check Dams

Abstract Debris flows in waterways can transport large amounts of sediment downstream, which can cause serious damage and economic losses. The vegetation cover in the valley of the Xiaojiang River in Yunnan Province, China—classified as a dry-hot valley—was significantly reduced by logging in the 1950s. Soil erosion intensified and 107 gullies developed, which led to debris flows along the 86 km length of the river. Jiangjia Gully is a tributary of the Xiaojiang River. Historically, debris flows have occurred frequently, blocking the Xiaojiang River seven times between 1957 and 2000. Since 2000, the construction of check dams and afforestation have decreased the volume of debris flows in the three tributaries of Jiangjia Gully. However, different combinations of check dams and afforestation were adopted in the three tributaries of Jiangjia Gully, which has led to the different trends in debris flows behaviour. A new method was established to evaluate the mitigative effect of check dams and afforestation on debris flows. We found that the debris flow volume was proportional to the gravity energy of soil and rock on the gully bank and inversely proportional to the vegetation coverage in a dry-hot valley setting. The method revealed that under different gravity energy conditions, the implementation order of check dam construction and afforestation is important for debris flow mitigation.

The effect of check dams on the dynamic and bed entrainment processes of debris flows

Landslides ◽  
2019 ◽  
Vol 16 (11) ◽  
pp. 2201-2217 ◽  
Author(s):  
Wei Shen ◽  
Dongpo Wang ◽  
Huanan Qu ◽  
Tonglu Li
Keyword(s):  
Debris Flows ◽  
Check Dams ◽  
Bed Entrainment

scholarly journals Numerical modeling using an elastoplastic-adhesive discrete element code for simulating hillslope debris flows and calibration against field experiments

2019 ◽  
Vol 19 (11) ◽  
pp. 2339-2358
Author(s):  
Adel Albaba ◽  
Massimiliano Schwarz ◽  
Corinna Wendeler ◽  
Bernard Loup ◽  
Luuk Dorren
Keyword(s):  
Numerical Model ◽  
Flow Velocity ◽  
Debris Flows ◽  
Field Experiments ◽  
Initial Conditions ◽  
Experimental Tests ◽  
Discrete Element ◽  
Height Velocity ◽  
Model Parameters ◽  
Fine Content

Abstract. This paper presents a discrete-element-based elastoplastic-adhesive model which is adapted and tested for producing hillslope debris flows. The numerical model produces three phases of particle contacts: elastic, plastic and adhesive. A parametric study was conducted investigating the effect of model parameters and inclination angle on flow height, velocity and pressure, in order to define the most sensitive parameters to calibrate. The model capabilities of simulating different types of cohesive granular flows were tested with different ranges of flow velocities and heights. The basic model parameters, the microscopic basal friction (ϕb) and ratio between stiffness parameters k1/k2, were calibrated using field experiments of hillslope debris flows impacting a pressure-measuring sensor. Simulations of 50 m3 of material were carried out on a channelized surface that is 41 m long and 8 m wide. The calibration process was based on measurements of flow height, flow velocity and the pressure applied to a sensor. Results of the numerical model matched those of the field data in terms of pressure and flow velocity well while less agreement was observed for flow height. Those discrepancies in results were due in part to the deposition of material in the field test, which is not reproducible in the model. Results of best-fit model parameters against selected experimental tests suggested that a link might exist between the model parameters ϕb and k1/k2 and the initial conditions of the tested granular material (bulk density and water and fine contents). The good performance of the model against the full-scale field experiments encourages further investigation by conducting lab-scale experiments with detailed variation in water and fine content to better understand their link to the model's parameters.

Two-dimensional numerical model for debris flows in the Jiangjia Gully, Yunnan Province

2011 ◽  
Vol 8 (6) ◽  
pp. 757-766 ◽  
Author(s):  
Hong Peng ◽  
Yanxin Zhao ◽  
Peng Cui ◽  
Wanshun Zhang ◽  
Xuejiao Chen ◽  
...  
Keyword(s):  
Numerical Model ◽  
Debris Flows ◽  
Yunnan Province ◽  
Two Dimensional ◽  
Jiangjia Gully
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