Help with retaining wall!


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Old 08-10-16, 05:49 PM
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Help with retaining wall!

I am building an outdoor pond and have a slight slope. to level the pond, i need to raise the opposite end by about 35 cm. The pond is 7m by 6m. That includes 1m width for plants that goes all around it and has a depth of 50cm.

Do i need a retaining wall? i think i do, at least on the wall with the pressure coming into the pond. or do i just compact add soil, add geotextile, add some soil, cover with membrane and fill it with water?? I want it to last so i am worried about the wall. See the image attached for a visual that i drew.

The excavation is done and it had rained. The water has accumulated and reached a level of 0.8m and has not drained in over a week!

I was thinking: after placing the membrane, I protect it with another liner and then using natural stones of about 6 inch in diameter, I cement them and build a wall up 1 meter and then continue at an angle to get to the horizontal area. That plus the water force should hold back preassure i assume.

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Love to hear what you experts think because i am by no means an expert! :-)
 
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Old 08-10-16, 06:56 PM
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I think the big thing is the aesthetic you want. An earthen dam can certainly work. I have a 100+ foot long x 20 foot high earthen dam for my pond. It was constructed 50+ years ago and survived 20 of those years without any maintenance. In your case I think the important thing is do you want the look of a retaining wall or a gently sloping hill? Both can be made to work and last.

Many books have been written about dam construction. Your's certainly won't be a large structure but tanking some tips from dam construction can help insure that it lasts but if you are lining your pond with a waterproof membrane then even many of the dam construction techniques aren't really needed. In your case I would go for earth using what was excavated when digging the pond. The more you can use clay type soil in the core of the dam the better. Then cap with topsoil for grass and other plantings.
 
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Old 08-10-16, 08:00 PM
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Thanks for the reply,

Down here in Mexico i have limited access to that information. I am in a small town. I can search online to see what i find though.

Standing inside i have the biggest side wall that are 4m x 1.2m high. You mean like use sand bags and pile them at an angle against that wall?
 
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Old 08-11-16, 07:52 PM
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anyone else has any tips?
 
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Old 08-12-16, 05:23 AM
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No sandbags. Soil/earth will be enough to contain your pond especially if your pond is lined with a waterproof liner. If you make the ground 6"-12" higher than the pond and 24" wide at the top before you slope down then the soil will have enough mass to resist the side force of the water.
 
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Old 08-12-16, 06:50 AM
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I believe you are refering to the left side of the image? I am more concerned about the left side collapsing in with time hence the reason i was thinking to build some concrete wall from the inside but on the 4 sides.
 
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Old 08-12-16, 07:18 PM
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Depending on your soil type, I think you could be asking for problems, by making the sides of your pond vertical, at the base. If the soil ever becomes saturated, the vertical areas will collapse into the pond. Membranes and mortared 6" rock won't cut it.

Either slope the sides, or build a true retaining structure. Reinforced concrete works well, and is relatively inexpensive if you batch it yourself.
 
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Old 08-13-16, 01:12 PM
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Thanks for the info, i think that is what i will do! reinforced concrete to be safe
 
 

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