Hydrodynamic Suction
Hydrodynamic Suction
(OP)
According to Indian code, the hydrodynamic pressure is same, whatever the direction - positive pressure or suction.
Should not the suction be limited to that of vacuum? How does water apply suction or tension on the face of a retaining wall or dam?
Thanks.
Should not the suction be limited to that of vacuum? How does water apply suction or tension on the face of a retaining wall or dam?
Thanks.






RE: Hydrodynamic Suction
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: Hydrodynamic Suction
Hope this helps.
Mike
RE: Hydrodynamic Suction
For such short questions they are very complex. I have other questions you may want to ask.
- How high might the lateral pressures be against the retaining wall upon wetting of the backfill? How much lateral movement might be anticipated as a result of the backfill becoming saturated?
- What are the magnitudes of active and passive earth pressures for the soil above the water table?
- Would the lateral pressures be related to the "swelling pressure" of the soil?
- How would infiltration along the top of your dam change your soil suction values and thus the stability of your dam?
These questions are very complicated even to the most senior geotechnical engineer. I would recommend that you talk to a local geotech engineer in your area for assistance. Sorry if I just complicated your questions even further. Good luck.
RE: Hydrodynamic Suction
The hydrodynamic forces are for fluid in motion over a spillway for example. If your crest is not designed correctly you will get uplift on your spillway or crest.
Consequently the ogee profile is calculated to ensure you do not get uplift at the design flood. At lower flows you will get pressure and at higher flows "suction".
This uplift occurs when you try and change the direction of the water flow quicker than gravity allows. Should the negative pressures become too high you get problems with cavitation