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Pressure On Wall

 
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venkatesh
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PostPosted: Sat Oct 28, 2017 6:39 am    Post subject: Pressure On Wall Reply with quote

Dear Sefians,
To calculate  earth or water pressure on retaining wall what should be the minimum distance of earth from retaining wall .It creates some confusion that even .5 m to 1m of water/ earth also exerts same pressure as per the formula? For example. I am attaching one file in which retaining wall is provided to retain .5 to 1m span  of water. I don't think water exerts full triangular pressure on bottom of the retaining wall. pl. clarify.

Thanks & Regards
R.Venkateshwar Rao



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venkatesh
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PostPosted: Tue Oct 31, 2017 8:18 am    Post subject: Reply with quote

Any Response ... ???
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arunangshu
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PostPosted: Wed Nov 01, 2017 6:28 am    Post subject: Reply with quote

Hydrostatic force varies with variation in piezometric head. As long as your piezometric head remains same, the pressure exerted on the wall remains same - independent of the thickness of fluid lamina.

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Arun
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es_jayakumar
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PostPosted: Wed Nov 01, 2017 8:09 am    Post subject: Reply with quote

The doubt here is that whether the thin layer / column of water is capable of destabilising the retaining wall, in practical sense. Theoretically it may be capable of doing so. It looks a bit complex.

E S Jayakumar
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arunangshu
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PostPosted: Wed Nov 01, 2017 8:33 am    Post subject: Reply with quote

If the thin layer is part of a continuous system, then it certainly can.
If its a isolated system/pocket then it may not.

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Arun
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venkatesh
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PostPosted: Wed Nov 01, 2017 1:18 pm    Post subject: Reply with quote

Mr  Er Jaykumar got my point. I think it won't exerts the force due to triangular pressure which may happen in normal conditions.

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Venkateshwar rao
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venkatesh
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PostPosted: Wed Nov 08, 2017 11:24 am    Post subject: Reply with quote

waiting for response from experts...

Thanks & regards
Venkateshwar Rao
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spsvasan
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PostPosted: Mon Nov 13, 2017 2:59 am    Post subject: Re: Pressure On Wall Reply with quote

venkatesh wrote:
Dear Sefians,
To calculate  earth or water pressure on retaining wall what should be the minimum distance of earth from retaining wall .It creates some confusion that even .5 m to 1m of water/ earth also exerts same pressure as per the formula? For example. I am attaching one file in which retaining wall is provided to retain .5 to 1m span  of water. I don't think water exerts full triangular pressure on bottom of the retaining wall. pl. clarify.

Thanks & Regards
R.Venkateshwar Rao




Dear Er.Venkateshwar

As far as I know, the water pressure on the wall depends only upon the height and does not depend upon the width of water body. Only if the width of water body becomes extremely small, capillary forces start influencing the pressure distribution

I have come across one failure of the base slab of an underground sump. The sump had been cast on rock. Since the base slab was resting on rock, the designer had assumed that there will be no uplift pressure and had provided only nominal reinforcement for the base slab. The fissures in rock allowed ground water to come into contact with the base slab. The small quantity of water in contact with the base slab was able to exert sufficient pressure and force to uplift the base slab and cause its failure.

Experts in hydraulics and physics will be able to provide a better answer

Soil behaviour is entirely different. Here, an inclined failure plane occurs. The angle of inclination of this failure plane depends upon the shearing resistance of the soil. The weight of the sliding soil wedge over the failure plane exerts the horizontal pressure on the wall. If the failure plane extends upto the surface, full pressure is exerted on the wall. If the width of the soil body is restricted and the failure plane is interrupted by rock or other body, the weight of sliding soil wedge above the failure plane reduces and lesser horizontal force is exerted on the retaining wall. This reduced pressure is considered in the design of deep silos, bins and bunkers

Hope the above is useful

S.P.Srinivasan
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venkatesh
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PostPosted: Mon Nov 20, 2017 5:55 am    Post subject: Reply with quote

Dear Er. vasan,
Thanks for your reply.

Thanks & Regards
Venkateshwar Rao
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