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Gary March 5, 2002 18:33

Debris flow simulations
 
Hi there,

I am wondering if there is any commercial software that can well simulate debris flows? I am studying some landslide cases. Ideally, I can reproduce these cases numerically.

Thanks in advance.

Gary

Herve March 7, 2002 05:19

Re: Debris flow simulations
 
Hi Gary,

Are you looking at the fluidization of the earth material and the forming of a kind of muddy flow slidding down? If such is the case there are means to do this using commercial codes, e.g. by altering the material properties with time or other variables or looking at solid fluid mixtures.

George Bergantz March 9, 2002 03:23

Re: Debris flow simulations
 
This is a difficult problem- not unlike the challange of fluidization where one must decide on what constitutive relations to use in the multiphase model. Plus real debris flows 'leak' fluids and sediment as they travel, and have a very large range of particle sizes- from fine mud to fist-sized clasts.

Dick Iverson at the USGS has what most regard as the best general papers on the physical models for debris flow, and in a recent edition of the journal called 'Geology' described some very useful simplifications for the rheological issues which are the key ones. In my recent discussions with him, it is clear that a truly robust numerical implementation is still some ways off, in part because of front-tracking problems as well leakage and irregular travel bed.

Some of the commercial codes have been modified to address these types of issues- in a fluidization framework. I don't know of any that have been actually applied to water-particle mixtures where there is a range of particle sizes that would be defendable in a court of law. The general two-fluid approach to multiphase flow that commercial codes use is difficult to implement for geological field conditions. I personally would be very suspect- that is wouldn't build my house down slope- on the results of such models. But others may have more informed opinions and I'd like to hear them.

Gary March 11, 2002 15:27

Re: Debris flow simulations
 
Dear George Bergantz

Thanks kindly for your informative discussions. I totally agree with you on the current status of debris study. I want to have some ideas on how the commercial codes deal with debris flow / landslides.

BTW, is the Iverson you mentioned Richard M Iverson at USGS ? His articles "The physics of debris flow" in "Reviews of Geophysics" (1997) is very impressive. Also, his Large-scale flume experiment greatly contributes to the debris flow study.

I do have another question for you as I realized you might be an expert in this field. The measurement of pore-water pressure during debris movement is difficult. Do you have any comment on its effect. I would be grateful if you could also provide some information on how should one measure the pore-water pressure.

Thanks a lot.

Gary

George Bergantz March 12, 2002 01:20

Re: Debris flow simulations
 
Gary:

I am an interested on-looker to the debris flow modeling (it is a very difficult problem just from the stand point of theory let alone numerical implementation)- but like you I hope to get into it. My interest is more in modeling volcanic eruptions and multiphase flow. I know that Dick Iverson has been working with Roger Denlinger on ways to resolve the flow-front problem using Reimann sums.

Regarding pore pressure I suggest that you contact Dick Iverson directly- he is a terrific guy and very helpful. His email address is:

riverson@usgs.notspamno.gov

Remove the notspamno to send.


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