Experimental study on discharge process regulation to debris flow with open-type check dams

Landslides ◽  
2020 ◽  
Author(s):  
Hao Sun ◽  
Yong You ◽  
Jinfeng Liu ◽  
Guangze Zhang ◽  
Tao Feng ◽  
...  
Keyword(s):  
Experimental Study ◽  
Debris Flow ◽  
Discharge Process ◽  
Open Type ◽  
Check Dams ◽  
Type Check

scholarly journals Analysis of Debris Flow Reduction Effect of Check Dam Types considering the Mountain Stream Shape: A Case Study of 2016 Debris Flow Hazard in Ulleung-do Island, South Korea

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Man-Il Kim ◽  
Namgyun Kim
Keyword(s):  
South Korea ◽  
Debris Flow ◽  
Observation Point ◽  
Mountain Stream ◽  
Check Dam ◽  
Open Type ◽  
Flow Reduction ◽  
Check Dams ◽  
Closed Type ◽  
Type Check

Ulleung-do is a volcanic island located 130 km east of the Gangwon-do province of South Korea. It is characterized by steep slopes covered with effusive rocks released from multiple volcanic activities. Having accumulated deep colluvium, Ulleung-do Island manifests a high vulnerability to landslides frequently caused by heavy rains or typhoons, debris flow, rockfall, and other disaster hazards in mountainous areas. Therefore, facilities and residential areas located in the lower areas of the island sustain widespread damage. Hence, the installation of check dams designed to reflect the area’s local conditions is required to avoid further damage. In line with that, this study analyzes the disaster cases in Ulleung-do’s mountain areas and the effect of check dams in debris flow reduction for each type using the KANAKO-2D model. At observation point 1, the result shows that the maximum rate of debris flow is reduced by 48.5% with an open-type check dam installed and 62.9% with a closed-type check dam installed from the level without a check dam. For observation point 2, the maximum flow depth decreases by 49.7% with an open-type check dam and 77.4% with a closed-type check dam. Thus, this study suggests that the simple installation of check dams in a mountain stream that has experienced debris flow effectively mitigates damage brought by various disasters.

Design Standard of Control Structures Against Debris Flow in Japan

2010 ◽  
Vol 5 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Nobutomo Osanai ◽  
◽  
Hideaki Mizuno ◽  
Takahisa Mizuyama ◽  
Keyword(s):  
Debris Flow ◽  
Flow Control ◽  
Warning Systems ◽  
Technical Standard ◽  
Stone Size ◽  
Control Structures ◽  
Open Type ◽  
Check Dams ◽  
Closed Type ◽  
Structural Measures

Countermeasures to prevent or mitigate sedimentrelated hazards, debris flow in this paper are classified as structural measures or nonstructural measures. The structural measures are Sabo dams, leading dikes, and channels for debris flow control. The nonstructural measures are the designation of areas prone to debris flow, proper land use in the areas, the reinforcement of houses, the creation of warning systems and the evacuation of the inhabitants in case of emergency. A technical standard on debris flow control structures of Japan was revised in 2007. Major revision is that check dams called Sabo dams constructed near houses are changed from closed type Sabo dams to open type Sabo dams because the occurrence frequency is low as once for longer than one hundred years, natural torrent environment should be conserved in ordinary days and sediment trap capacity should be kept until debris flow occurs. Points changed are explained such as the opening of open type dams is as equal as the maximum stone size.

scholarly journals Method to evaluate the effect of inclination angle of steel open-type check dam on debris flow impact load

2018 ◽  
Vol 10 (1) ◽  
pp. 95-115 ◽  
Author(s):  
Toshiyuki Horiguchi ◽  
Yoshiharu Komatsu
Keyword(s):  
Debris Flow ◽  
Natural Disasters ◽  
Inclination Angle ◽  
Impact Load ◽  
Time History ◽  
Check Dam ◽  
Open Type ◽  
Inclination Angles ◽  
The Impact ◽  
Type Check

Although the latest statistics indicate a decrease in the number of victims of natural disasters in Japan, the number of sediment disasters has increased. A countermeasure against natural disasters is provided by the installation of a steel open-type check dam (hereafter, open Sabo dam). The open Sabo dam is expected to capture boulders (more than 1.0 m in diameter) contained in debris flow of which boulders concentrate in front part. When a debris flow impacts an open Sabo dam, the large impact load on the steel pipes are caused by the impact of boulders under debris flow. Therefore, it is important to evaluate the impact of both boulders and the following soil and small gravels including fluid force of the open Sabo dam from the design point of view. Although an open Sabo dam has various shapes especially, the every open Sabo dams is evaluated by the same design method in Japan. It is necessary to propose the load evaluation method in the experiment scale in contrast with different shape of open Sabo dam. This article presents an experimental approach to determine the effect of the front inclination angle of steel open Sabo dams on the impact load. The debris flow impacts 1/40 scale models of steel open Sabo dams which are set in a flow channel flume, and the debris flow load is measured by using three load cells placed horizontally at the back of the Sabo dam model. Different front inclination angles are set for each Sabo dam models. The time history of the impact load is examined by comparing the loads corresponding to four kinds of dams, which are different from the front inclination angles, and decrease of impact load considering the buffering effect of driftwoods in debris flow.

Deposition Prediction of Debris Flow Alluvial Fan Based on Experimental Study

2012 ◽  
Vol 518-523 ◽  
pp. 4819-4822
Author(s):  
Jin Feng Liu ◽  
Shun Yang ◽  
Guo Qiang Ou
Keyword(s):  
Experimental Study ◽  
Debris Flow ◽  
Statistical Method ◽  
Laboratory Experiments ◽  
Empirical Models ◽  
Alluvial Fan ◽  
Disaster Prevention ◽  
Average Accuracy ◽  
Hazardous Area ◽  
Debris Flow Disaster

The deposition prediction of debris flow hazardous area is very important for organizing and implementing debris flow disaster prevention and reduction. This paper selected the data base from laboratory experiments and applied the multiple regression statistical method to establish a series of empirical calculation models for delimiting the debris flow hazardous areas on the alluvial fan. The empirical models for predicting the maximum deposition length (Lc), the maximum deposition width (Bmax) and the maximum deposition thichness (Z0) under the condition of different debris flow volumes (V), densities (rm) and slopes of accumulation area (θd) were establised. And the verification results indicated that the established models can predict the debris flow hazards area with the average accuracy of 86%.

Multi-temporal analysis of the role of check dams in a debris-flow channel: Linking structural and functional connectivity

Geomorphology ◽  
2019 ◽  
Vol 345 ◽  
pp. 106844 ◽  
Author(s):  
Sara Cucchiaro ◽  
Federico Cazorzi ◽  
Lorenzo Marchi ◽  
Stefano Crema ◽  
Alberto Beinat ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Debris Flow ◽  
Temporal Analysis ◽  
Flow Channel ◽  
Check Dams ◽  
Multi Temporal

Are Torrent Check-Dams Potential Debris-Flow Sources?

2015 ◽  
pp. 485-488 ◽  
Author(s):  
Jošt Sodnik ◽  
Manica Martinčič ◽  
Matjaž Mikoš ◽  
Andrej Kryžanowski
Keyword(s):  
Debris Flow ◽  
Check Dams

Experimental Study on Gravity Driven Discharging of Quasi-Two-Dimensional Pebble Bed Based on Mathematical Morphology

2020 ◽  
Author(s):  
Yujia Liu ◽  
Sifan Peng ◽  
Nan Gui ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Mathematical Morphology ◽  
High Speed ◽  
Three Dimensional ◽  
Reactor Core ◽  
Engineering Application ◽  
Discharge Process ◽  
Two Dimensional ◽  
Pebble Bed ◽  
Gravity Driven

Abstract The pebbles flow is a fundamental issue for both academic investigation and engineering application in reactor core design and safety analysis. In general, experimental methods including spiral X-ray tomography and refractive index matched scanning technique (RIMS) are applied to obtain the identification of particles’ positions within a three-dimensional pebble bed. However, none of the above methods can perform global bed particles’ position identification in a dynamically discharging pebble bed, and the corresponding experimental equipment is difficult to access due to the complication and high expense. In this research, the experimental study is conducted to observe the gravity driven discharging process in the quasi two-dimensional silos by making use of the high-speed camera and the uniform backlight. A mathematical morphology-based method is applied to the pre-processing of the captured results. After being increased the gray value gradient by the threshold segmentation, the edges of the particles are identified and smoothed by the Sobel algorithm and the morphological opening operation. The particle centroid coordinates are identified according to the Hough circle transformation of the edges. For the whole pebble bed, the self-programmed process has a particle recognition accuracy of more than 99% and a particle centroid position deviation of less than 3%, which can accurately obtain the physical positions of all particles in the entire dynamically discharge process. By analyzing the position evolution of individual particles in consecutive images, velocity field and motion events of particles are observed. The discharging profiles of 5 conditions with different exit are analyzed in this experiment. The results make a contribution to improving the understanding of the mechanism of pebbles flow in nuclear engineering.

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