looks like its starting to go in the middle..or someone has a bum eye..

Thanks to Jorgo for the good website. I was working in Laos when my wall was built, so I entrusted the job to my wife and her friend. I assumed he knew what he was doing, that was my mistake. Next time I'll pay more attention, and make sure it's done right. Live and learn...

I am about to embark on a build with the first stage being a retaining wall. Thanks Udonhoward for your posts - a timely reminder for me of what can (and does) go wrong. I have a similar scenario, being surrounded by paddy fields on three sides. There are lots of websites from our home countries with design criteria for different facets of building, and in my case I have had a look at various Australian government sites, as well as building product suppliers (such as Boral) to get some good background knowledge on designing retaining walls. The biggest problem with Howard's first wall (as he pointed out) seems to have been with drainage. A slotted agricultural (aggie) pipe should be laid longditudinally at the base of the wall, with outlets thru the wall every few metres. The aggie pipe should be covered with a fine mesh drainage sock to keep the aggie pipe from getting clogged up with silt. Aggregate 30 cms wide should be placed against the wall, allowing water to find its way down to the drainage system and outside. The rest of the spoil can then be backfilled up to the aggregate. Best practice would be to cover the aggregate with an impervious material sloping to a spoon drain against the wall leading to an open drain.
Of course the wall itself needs careful design consideration. As Coxo says, the wall needs to be solid concrete up to the fill level. Masonry blocks can be used, backfilled with concrete and reinforced both vertically and horizontally every 40 cms with N12 rebar. The concrete protects the rebar in the longterm, as well as adding considerable weight for stability. According to Boral's specs, 140 mm blocks can be used in this fashion to a maximum retaining height of 1.2 m. (which is more than the maximum in my case.
I will go for a little overkill, with anchor columns at approx. 6.5 m centres on large reinforced foundations as far below outside ground level as the height of the retained fill at that point. I have trucks carrying sugar cane along a very narrow easement on one side, so other precautions are necessary. The wall will be half a metre inside my boundary, but there will be brightly coloured, large guage RSJs (think railway line) concreted vertically into the ground along the western boundary (not connected to the wall), to protect my garage (which will be connected to the wall).

A link to Boral's masonry products PDF. The retaining wall section starts at page B 11. Someting to consider if you do use corefilled and reinforced masonry block is a waterproofing treatment on the inside of the wall - otherwise you will never keep paint on the outside.
http://www.boral.com.au/masonry-design- ... al_bk1.pdf

A couple of coats of paint would of helped the rain not penetrating the wall and making it 3 times its own weight.i never see copings on a wall out here and the tops of walls left bare to soak it all up.try leaving a block in water for a few hours and feel the weight against a dry one.the blocks here are of a low density and act as a nice sponge or weetabix.

Also remember in future not to plant trees near your wall.

not to plant trees near the wall , Try telling that to my misses , hy guys , ive tied to find a post that i posted on about walls etc , can't find it , so here goes , the discussion was where to find a company that does piled posts with serious concrete slats/beams between posts ,( ive never seen one of these fail as of yet , ) also used for retaining , i have now found one ,it's CPU ,location Udonthani ,on the road going east at the traffic lights near the original Global house ,yet to go and discuss my requirements with them , Talking to a man who has had his wall built by them ,,,maybe 1 Rai area 2mtrs high ( don't know how deep , )i was surprised at the cost , i was expecting double what he paid ,

Thanks for the info Hoopoe. I will have a chat with them too.

I'm about to get walls built by World Concrete.
Same as you describe.
I am very impressed with their professionality and price.
I visited the Depot in picture.
Mick