Erosion Mechanism of Dam Lands and Flow Characteristics of Dam Breaks under Check-Dam-Break Conditions

2021 ◽  
Author(s):  
Maohua Le ◽  
Qingchao Guo ◽  
Zhijian Wang ◽  
Lei Zhang
Keyword(s):  
Flow Characteristics ◽  
Dam Break ◽  
Check Dam ◽  
Erosion Mechanism ◽  
Dam Breaks

scholarly journals Experimental Research on the Dam-Break Mechanisms of the Jiadanwan Landslide Dam Triggered by the Wenchuan Earthquake in China

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Fu-gang Xu ◽  
Xing-guo Yang ◽  
Jia-wen Zhou ◽  
Ming-hui Hao
Keyword(s):  
Wenchuan Earthquake ◽  
Discharge Channel ◽  
Landslide Dam ◽  
Dam Break ◽  
Experimental Results ◽  
Dam Breaks ◽  
The Wenchuan Earthquake ◽  
Large Numbers ◽  
Dam Management ◽  
Break Process

Dam breaks of landslide dams are always accompanied by large numbers of casualties, a large loss of property, and negative influences on the downstream ecology and environment. This study uses the Jiadanwan landslide dam, created by the Wenchuan earthquake, as a case study example. Several laboratory experiments are carried out to analyse the dam-break mechanism of the landslide dam. The different factors that impact the dam-break process include upstream flow, the boulder effect, dam size, and channel discharge. The development of the discharge channel and the failure of the landslide dam are monitored by digital video and still cameras. Experimental results show that the upstream inflow and the dam size are the main factors that impact the dam-break process. An excavated discharge channel, especially a trapezoidal discharge channel, has a positive effect on reducing peak flow. The depth of the discharge channel also has a significant impact on the dam-break process. The experimental results are significant for landslide dam management and flood disaster prevention and mitigation.

scholarly journals A 2D HLL-based weakly coupled model for transient flows on mobile beds

2020 ◽  
Vol 22 (5) ◽  
pp. 1351-1369
Author(s):  
Robin Meurice ◽  
Sandra Soares-Frazão
Keyword(s):  
Numerical Models ◽  
Morphological Evolution ◽  
Coupled Model ◽  
Dam Break ◽  
Water Levels ◽  
Test Cases ◽  
Transient Flows ◽  
Dam Breaks ◽  
Weakly Coupled ◽  
High Interaction

Abstract We propose a finite-volume model that aims at improving the ability of 2D numerical models to accurately predict the morphological evolution of sandy beds when subjected to transient flows like dam-breaks. This model solves shallow water and Exner equations with a weakly coupled approach while the fluxes at the interfaces of the cells are calculated thanks to a lateralized HLLC flux scheme. Besides describing the model, we ran it for four different test cases: a steady flow on an inclined bed leading to aggradation or degradation, a dam-break leading to high interaction between the flow and the bed, a dam-break with a symmetrical enlargement close to the gate and a dam-break in a channel with a 90° bend. The gathered results are discussed and compared to an existing fully coupled approach based on HLLC fluxes. Although both models equally perform regarding water levels, the weakly coupled model looks to better predict the bed evolution for the four test cases. In particular, its results are not affected by an excessive numerical diffusion encountered by the coupled model. Moreover, it usually better estimates the amplitudes of the maximum deposits and scours. It is also more stable when subject to high bed–flow interaction.

scholarly journals Dam Break Analysis of Gembong Dam Using Zhong Xing HY21

2021 ◽  
Vol 930 (1) ◽  
pp. 012091
Author(s):  
K E Milleanisa ◽  
P T Juwono ◽  
R Asmaranto ◽  
M Ayu
Keyword(s):  
Flood Control ◽  
Dam Break ◽  
Dam Construction ◽  
Design Flood ◽  
Dam Breaks ◽  
Inundation Area ◽  
High Hazard ◽  
Inundation Height ◽  
The Impact ◽  
Very High

Abstract Dams are a form of effort to conserve or protect water resources. The function of the Dam as a reservoir for water, irrigation, power generation, and flood control. However, in addition to its huge benefits, dam construction also can endanger the community’s safety, namely in the form of dam breaks. The main causes of dam break are overtopping and piping. So that analysis is needed related to dam break to minimize the impact. Based on the Zhong Xing HY21 software, the most severe impact of the break of the Gembong Dam was due to overtopping using the QInflow PMF design flood of 724.142 m3/s. It resulted in an inundation area of 54.682 km2 with a maximum inundation height of 5.129 m. As a result of the break of the Gembong Dam, 37 villages downstream of the Gembong Dam were flooded. There are 80.819 people affected by this risk. It is stated that all affected villages are at the 4th hazard classification level or very high hazard.

scholarly journals DAM BREAK WAVE, TIDAL BORE, IN-RIVER TSUNAMI SURGE: WHAT THE HELL?

2020 ◽  
pp. 14
Author(s):  
Hubert Chanson
Keyword(s):  
Current Knowledge ◽  
Leading Edge ◽  
Air Entrainment ◽  
Dam Break ◽  
Cfd Modelling ◽  
Dam Breaks ◽  
Physical Experiments ◽  
Tidal Bores ◽  
2004 Tsunami ◽  
Physical Analogy

Flood waves resulting from dam breaks have been responsible for numerous losses of life through centuries. Both the 26 December 2004 tsunami and 11 March 2011 Tohoku catastrophes were human tragedies of international significance. An important point is the physical analogy between dam break waves travelling downstream, tidal bores progressing deep inland, in-river tsunami propagating upstream, as well rejection surges in hydropower canals. The leading edge is a hydrodynamic shock, with a marked discontinuity in free-surface elevation and velocity and pressure fields, and a tri-phase flow with three distinct flowing phases, i.e. liquid (water), solid (sediment) and gas (air). Seminal features of bores and surges include a net mass flux, the breaking in shallow waters, and the intense turbulence at the front associated with massive sedimentary processes and air entrainment in the breaking roller. In this keynote talk, physical experiments, numerical CFD modelling and field observations are presented and compared. Current knowledge gaps are discussed. Ultimately it is argued that the 'solitary wave' analogy is not directly relevant to model the unsteady turbulent mixing of in-river tsunami surges, tidal bores and dam break waves.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/SQaPoSj2lP4

Evaluation of the risk of the breaking of check dam based on a scorecard model.

2021 ◽  
Author(s):  
beilei liu ◽  
peng li ◽  
zhanbin li ◽  
yuanyuan yang ◽  
shaobo long ◽  
...  
Keyword(s):  
Storage Capacity ◽  
Operation Time ◽  
Control Area ◽  
Dam Break ◽  
Information Value ◽  
Low Risk ◽  
Average Risk ◽  
Check Dam ◽  
Maximum Rainfall ◽  
Storage Volume

<p>Check dam is a line of defense in the comprehensive watershed management system, but with the extended operation time, the operational risk of check dam increases, coupled with the frequent occurrence of sudden heavy rainfall under the influence of climate change in recent years, further increasing the risk of dam break.</p><p>In this study, to address the current problem of untimely detection of potential dam break risk of check dam in China, we use the common variable screening based on WoE (Weight of Evidence) and IV (Information Value), establish a score card model based on logistic regression method, use KS curves and statistics, and AUC values for model evaluation, and analyze the 2016 From 22:00 on August 16 to 12:00 noon on August 17, 2016, a dam break was formed by a large rainstorm in Dalat Banner.</p><p>The following conclusions were obtained: The IV values of each variable, such as control area, total storage capacity, siltation area, storage volume, and maximum rainfall, were all greater than 0.1, and each variable had more than moderate predictive power as a function of the breaking of check dam, that is, each factor had an effect on the breaking of check dam.The IV values of precipitation factors are higher than those of check dam factors. The influence probability of precipitation factors on the breaking of check dam is about 67%, and the influence probability of check dam factors on the breaking of check dam is about 33%.Precipitation is a direct factor affecting the breaking of check dam, and the maximum 6-hour precipitation has the most significant effect; among the check dam factors, the control area, storage volume, and flood storage capacity have a greater effect on the breaking of check dam, accounting for more than 10%, while the siltation volume and depth have a smaller effect on the breaking of check dam, accounting for 2.85% and 2.89% respectively.Very low risk which check dam with a score of 95 or higher account for about 43%, low risk for 28%, average risk for 15%, and higher risk for 7%. Very high risk accounted for 5% and there was only one dam with danger which is rated below 10.</p><p>This study aims to monitor and warn the operation of check dam to ensure the safe operation of the check dam system and maintain the ecological security of the Loess Plateau.</p>

Experimental and SPH studies of reciprocal wet-bed dam-break flow over obstacles

2021 ◽  
pp. 2150098
Author(s):  
Armin Ansari ◽  
Ehsan Khavasi ◽  
Jafar Ghazanfarian
Keyword(s):  
Surface Deformation ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Dam Break ◽  
Experimental Results ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dam Break Flow ◽  
Velocity Effect

Different permutations of the single and the two-fold dam-break flow have been investigated using the mesh-free smoothed-particle hydrodynamics and the experimental setup. The free-surface deformation in the case with the wet bed for five different downstream water heights has been investigated and respective numerical and experimental results were presented. The results demonstrate that the increase of the water height over the wet bed leads to the reduction of the flow front velocity. Effect of considering or omitting the dam gate during the numerical simulation has also been examined, which proves that the simulations including the dam gate show improved agreement with the experimental results. Influence of the three-dimensional cubic, triangular, circular and square cylindrical obstacles and their position on flow characteristics has been investigated. As the distance between the triangular obstacle and the gate increases, a bore is created at the position closer to the top of the triangle. In addition, it is found that larger force is exerted on the circular cylinder in comparison to the square cylinder.

scholarly journals Analysis of Social and Environmental Impact of Earth-Rock Dam Breaks Based on a Fuzzy Comprehensive Evaluation Method

2020 ◽  
Vol 12 (15) ◽  
pp. 6239 ◽  
Author(s):  
Hao Gu ◽  
Xiao Fu ◽  
Yantao Zhu ◽  
Yijun Chen ◽  
Lixian Huang
Keyword(s):  
Environmental Impact ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Dam Break ◽  
Evaluation Index System ◽  
Fuzzy Comprehensive Evaluation Method ◽  
Comprehensive Evaluation Method ◽  
Dam Breaks ◽  
The Social

A large proportion of the dams in China are earth-rock dams. Regarding the well-studied loss of life and economic consequences due to dam breaks, this paper introduces the causes and modes of earth-rock dam breaks and the corresponding dam-break losses in terms of the social and environmental aspects. This study formulates the evaluation index system and criteria of earth-rock dam breaks’ impact on society and the environment based on a fuzzy comprehensive evaluation method. The results show that the evaluation grade of the social and environmental impact of the dam break of the Liujiatai Reservoir was “serious”. Therefore, similar dams in China should take corresponding measures in advance to reduce the social and environmental impact of earth-rock dam breaks.

scholarly journals Three-dimensional numerical simulation of mud flow from a tailings dam failure across complex terrain

2019 ◽  
Author(s):  
Dayu Yu ◽  
Liyu Tang ◽  
Chongcheng Chen
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Dam Break ◽  
Dam Failure ◽  
Tailings Dam ◽  
In Situ Investigation ◽  
Impact Area ◽  
The Impact ◽  
Mud Flow

Abstract. A tailings dam accident can cause serious ecological disaster and property loss. Simulation of a tailings dam accident in advance is useful for understanding the tailings flow characteristics and assessing the possible extension of the impact area. In this paper, a three-dimensional (3-D) computational fluid dynamics (CFD) approach was proposed for reasonably and quickly predicting the flow routing and impact area of mud flow from a dam failure across 3-D terrain. The Navier–Stokes equations and the Bingham-Papanastasiou rheology model were employed as the governing equations and the constitutive model, respectively, and solved numerically in the finite volume method (FVM) scheme. The volume of fluid (VOF) method was used to track the interface between the tailings and air. The accuracy of the CFD model and the chosen numerical algorithm were validated using an analytical solution of the channel flow problem and a laboratory experiment on the dam break problem reported in the literature. In each issue, the obtained results were very close to the analytical solutions or experimental values. The proposed approach was then applied to simulate two scenarios of tailings dam failures, one of which was the Feijão tailings dam that failed on 25 January 2019, and the simulated routing coincided well with the in situ investigation. Therefore, the proposed approach does well in simulating the flow phenomenon of tailings after a dam break, and the numerical results can be used for early warning of disasters and emergency response.

scholarly journals Dynamic decision making for dam-break emergency management – Part 1: Theoretical framework

2013 ◽  
Vol 13 (2) ◽  
pp. 425-437 ◽  
Author(s):  
M. Peng ◽  
L. M. Zhang
Keyword(s):  
Decision Making ◽  
Emergency Management ◽  
Companion Paper ◽  
Decision Criterion ◽  
Dam Break ◽  
Dynamic Decision Making ◽  
Dam Failure ◽  
Analysis Model ◽  
Dam Breaks ◽  
New Information

Abstract. An evacuation decision for dam breaks is a very serious issue. A late decision may lead to loss of lives and properties, but a very early evacuation will incur unnecessary expenses. This paper presents a risk-based framework of dynamic decision making for dam-break emergency management (DYDEM). The dam-break emergency management in both time scale and space scale is introduced first to define the dynamic decision problem. The probability of dam failure is taken as a stochastic process and estimated using a time-series analysis method. The flood consequences are taken as functions of warning time and evaluated with a human risk analysis model (HURAM) based on Bayesian networks. A decision criterion is suggested to decide whether to evacuate the population at risk (PAR) or to delay the decision. The optimum time for evacuating the PAR is obtained by minimizing the expected total loss, which integrates the time-related probabilities and flood consequences. When a delayed decision is chosen, the decision making can be updated with available new information. A specific dam-break case study is presented in a companion paper to illustrate the application of this framework to complex dam-breaching problems.

Study on the Gray Fuzzy Comprehensive Evaluation Model about Dam-Break Consequences

2012 ◽  
Vol 594-597 ◽  
pp. 1965-1968
Author(s):  
Xiao Ling Wang ◽  
Qing Song Wang ◽  
Rui Rui Sun ◽  
Xue Fei Ao
Keyword(s):  
Comprehensive Evaluation ◽  
Environmental Influence ◽  
Evaluation Model ◽  
Three Dimensional ◽  
Fuzzy Comprehensive Evaluation ◽  
Economic Loss ◽  
Dam Break ◽  
Loss Of Life ◽  
Dam Breaks ◽  
The Social

The comprehensive evaluation of the dam-break consequences is an issue of crucial importance for defending natural disasters, protecting socio-economic and sustaining ecological development. The consequences of dam-break were analyzed, including life loss, economic loss and the social and environmental influence. The loss of life evaluation based on the improved Graham method was introduced. Depth, velocity and other hydraulic parameters of dam-break flood were obtained by the three-dimensional numerical simulation, which has proved to be a useful tool for dam-break consequences. AHP method was adopted to measure the weight of each factor. Grey fuzzy comprehensive evaluation of dam-break consequences was proposed. QING LINJING reservoir in Shenzhen was taken as a case. The results show that it will cause serious incidents once QING LINJING reservoir dam breaks.

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