Howie wrote:

On Wed, 1 Sep 2004 12:03:47 +0100, "Mike Taylor"
wrote:

|for that height and length you will need without fail to get a structual
|engineer to design your wall. If you know nothing about it then do not even
|start. 10' high by 18' long is an enormous amount of weight. You will also
|have a problem constructing it due to possible slip unless it is designed
|properly.
|Back to your original question about hollow concrete blocks then yoes in
|principle what you have said is standard practise for smaller retaining
|walls.
|
Thanks for the help.

Really, I am viewing this as only a garden wall, - it's nowhere
near the house at all and there is no structure behind it. Also,
I was only putting a hard-standing on the lower side to use as a
carport, (maybe convert to a garage later). So basically, I was
hoping to avoid paying a structural engineer by asking here
instead!

I'm glad my thoughts on the hollow block with steel is a good
starting point. Appreciate your help.


It is,.

Retaining walls are an interesting thing.

Natural slip angle of scree and we soil is about 40 degrees: And wall
that is more 'vertical' than that needs to be designed to take a thrust
force off the soil.

Classic methods are using steel ties back to buried blocks that take the
pressure, or a curved and slightly sloping wall like a dam has.

The worst possible wall is tall thin and vertical and flat.

Make it much wider at the base, and dig it into the soil to the foot
doesn't slide.

If you lay horizontal steel, you can have it convex, but best is to make
it concave like an arch laid on its side.

Buttresses are good things if you can't make it slope.

What would I do?

Make it parabolic in plan, and dig down a couple of feet below lowest
ground level and lay a concrete base with reinforcing in it.

Then build using blocks steel rods and plenty of ties to make at least
double concrete block at top, going to 3-4 blocks wide at the base, and
use a buttress every 10 ft or so of at least a block width. Tie it all
together with ties at every point.

Leave drainage in the wall base, or put a soakaway of gravel and a pipe
there to prevent water build up.

Back fill with loose rubble and gravel and use some polystyrene sheet of
about 3" thick against the uphill side of the wall, to allow for some
'give'.


Won't hold a landslide, but won't start one either...



H.