Dam Break

[Labonia]

Hi,
I have a problem in the simulation of Dam Break in Hec Ras on the sudden collapse of the dam. How should I do?
Regards

[Anonymous]

What is the problem that you are having? Is it a numerical stability issue or a question of how to use RAS for the scenario that you are interested in? A bit more info. would be useful.

[Labonia]

My problem consists in the procedure to be used for the collapse of Ras improvviso.Ho has tried to simulate the sudden collapse , after entering the various geometric data with a linear type :
Time Fraction Fraction Breach
0 1
0.5 1
1 1
using this expression invaded upstream does not empty .
I would like to know if the procedure I used is correct or there is another procedure to be applied .I would be grateful for the resolution of the problem.

[Labonia]

Hi,
I could use a tutorial of Dam Break explaining in detail all the steps to do and an example to solve my problem .
Where can I find it?

[Anonymous]

The HEC publication TD-39 “Using HEC-RAS for Dam Breach Studies” is a thorough document on this subject. It can be found at: http://www.hec.usace.army.mil/publications/TrainingDocuments/TD-39.pdf

[Labonia]

Hi,
publication in the TD- 39 is not mentioned the procedure to be carried out by the sudden collapse of a gravity dam for which the publication was not helpful to the resolution of my problem .The would be grateful for more information .

[Anonymous]

The algorithm in HEC-RAS for computation of a dam failure outflow hydrograph does not include an instantaneous failure. In HEC-RAS, the failure time is finite. So, the time for the development of the breach and subsequent, computed, breach outflow hydrograph are done within several computational time steps. Should you wish to model a situation with an instantaneous breach, you might want to develop the breach outflow hydrograph external to RAS and input it as an upstream flow hydrograph. Perhaps you will find HEC document RD-8 “Dimensionless Graphs of Floods From Ruptured Dams” useful.

[Robert]

Good day,

You have a right, that a concrete dam failure is suddendly (Qmax=0h:0m)

I was solving concrete dam break using method level-pool routing, because I had a limited input data (volume curve) for reservoir. (I couldn’t use dynamic routing method)

After, you have to determine a breach characteristic (location, shape and size) in the concrete dams.

Example:
Location- near a functional object (weir gate)
shape and size- the entire block as the foundation/base/ground

Some printscreen from my project (see links)
https://drive.google.com/file/d/0B6wWUzbPUM0dMERpV2tvNDhTRDA/view?usp=sharing
https://drive.google.com/file/d/0B6wWUzbPUM0dZWxOV0dpT0ZSVUE/view?usp=sharing
https://drive.google.com/file/d/0B6wWUzbPUM0dT3RudGcwN2dPSEk/view?usp=sharing

Regards!
Robert

[sotiris]

Hello everyone,
I am trying to simulate a dam break due to piping but I do not know if there are regression models for this type of failure, apart from Froehlich 1995 and 2008. Could someone give me some hints? Thanks in advance

[Robert]

Hi

This is difficult question for:
large or small dam
earth dam or rockfill dam

I think, you should use all equations for breach parameters estimations. Then you can/should compare your results (parameters of dam, width of breach, failure of breach) with database of failure dams (Bureau of reclamation- 108 case of dams failure).

By the way: i would choose a Froehlich 2008 🙂

regards!
robert

[Anonymous]

Hi! Robert is it possible to share the steps or some sort of tutorial to model the Dam break analysis? Because I also want to do the same thing in Hecras.

[Robert]

Hi

I recognize you these documents:
1. Create of model by HEC-RAS
https://drive.google.com/file/d/0B6wWUzbPUM0dNmo3RnViUDJwR28/view?usp=sharing

2. Estimating of breach parameters and Downstream flood-wave routing
https://drive.google.com/file/d/0B6wWUzbPUM0delV2ZmFlTTB1Q0k/view?usp=sharing

I hope, that I help you. In case of uncertainty, you can write me!

have a nice day
Robert

[emtithal]

please I need advice about ras result
the value velosity is very big, Idon’t know the reason

[Anonymous]

These channel velocities might be valid. Assuming that the RAS run converged OK and it’s a subcritical reach. The reproduction of the Teton Dam failure with RAS shows channel velocities in the range of 4 to >7 m/sec.

[emtithal]

Thanks for your advice
But my teacher lell me” the values of velicity not logical”
Ican’t calibration for reach because I don’t have data so, I assum value Manning’s between (0.035 – 0.06) because the ground surface very hard , also the water during the break walk quikly
I will try uplowde my project for help me
Again Thanks

[Author]

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