retaining wall advice, materials and joints

[poopong]

I plan to build a retaining wall, about 24 m long with three corners. Approximately 3m + 9m + 10m + 3m. The ground is very stable chalk and there would be no significant loads on the retained soil.

Options I am considering are

1. 100 mm x 215mm x 440 blocks laid on their flats (belly down)
2. The same blocks but laid conventionally (face out) as a "cavity wall" with ties
3. Hollow concrete blocks, no infill or rebar
4. Hollow concrete block, with concrete infill and rebar

If not using rebar, I might include engineering bricks as come out of ground level.

Following advice, I'd probably include some piers on the retaining face, every 3 -4 m.

Which of the above would be most appropriate? All concrete will have to be done with a mixer due to access / distance from road.

I'm assuming your recommendation will mostly be based on personal taste / preference as they all seem adequate to me (rebar seems overkill). However, I am more confused over the need (or not) for control/expansion/contraction joints in a concrete block retaining wall.

https://www.cba-blocks.org.uk/wp-co...kr5dsMTKJIpCMn9TP1TLrRW-BP7wdK2jwnfuMDE4dfigo

Following some guidance from elsewhere, am I now correct in thinking that such joints are not required in a garden retaining wall? Or are they required unless the wall is fully buried (e.g. foundation)? Every 6 m - 9 m appears to be the advice but would they introduce an unwanted weak point in a retaining wall? Yes, I am aware that ties and sliding pins can be used but this seems unnecessarily complex for an otherwise simple garden wall.

Thanks for any advice you can give.

 

[^woody^]

The wall will expand and contract and if it cracks that's much weaker than a tied expansion joint.