Do my retaining walls need pillars

[Cian]

Hey,

I'm in the process of digging foundations for two retaining walls. 400mm deep x 450mm wide.
I'm going to lay solid blocks on flat. 440x100x215. So the wall will be 215mm thick and 1.2metres high.

One wall is 5metres long and the other 7metres. Do I need any extra pillars or piers for strengthening these walls?

Thanks in advance.

 

[^woody^]

Not as long as the foundation is deep and wide enough, and you install drainage.

What is being retained?

Are these walls joined? (should have a movement joint)

How are the wall ends being left?

 

[Cian]

Hey,

So there's about 500mm of soil then there'll be hardcore and then a layer of concrete on top. Acting as a patio.

Walls are divided by a few steps.

Walls ends will stop at steps in the middle and up against garden boundary walls on the far ends.

Thanks.