17 foot High Block Wall?

[aztecaa]

I have a lot that is on the side of the hill.
I have excavated and cut into the hill.
It is about 17 feet high at the back.
At the bottom of where I plan to pour cement onto a rock bed compacted down into the dirt trench. (lots of rock in the hill and floor)

WILL... 15X20X40cm cinder blocks with rebar every 40cm (cement Fill cores) apart and (rebar/rings wired) pilaster erected every 6-7 feet apart and another (rebar/ring wired) horizontal joint reinforcement every 5 feet high.(will back fill also)
An L at each end approximately 12' end to end.
A 2' wide rebar footings every 40 cm wired to horizontal (rebar/rings wired), laid on a level, compacted CEMENT base 8"X4" (cement form) to set the first level of blocks on.
Suffient enough to hold the dirt back?

Also ...WHERE or how high do I set the perforated 4" Tube behind the the block retaining wall?

[concretemasonry]

A 15 cm block is not thick enough for a 17' high wall.

Where are you located? What kind of soil and climate do you have there? What strength block are available?

This should be designed by an engineer that takes into account of all the factors. The ACI 530 codes and specifications should be used.

I have seen 20 story loadbearing block (150 mm thick) buildings without concrete or steel columns and beams, but the all the factors were considered and they used different strength block where required.

Dick