Retaining wall blinding layer for the shear key

[Tangogreen]

Hello
I am building a high retaining wall. I have the engineer designs. There is a 1.5m x 6m reinforced slab which is has a sheer key so is both 25cm and 50cm deep. The first 1.05m is 25cm deep and the next 45cm is 50cm deep. It is specified to be concreted above a blinding layer of compacted 5cm MOT. I can't figure out how to get the MOT to stick to the edge of what I can only call a sheer cliff! Does it mapper if there is little or no blinding on the cliff edge?
Would be most grateful for any advice!

 

[noseall]

Hello
I am building a high retaining wall. I have the engineer designs. There is a 1.5m x 6m reinforced slab which is has a sheer key so is both 25cm and 50cm deep. The first 1.05m is 25cm deep and the next 45cm is 50cm deep. It is specified to be concreted above a blinding layer of compacted 5cm MOT. I can't figure out how to get the MOT to stick to the edge of what I can only call a sheer cliff! Does it mapper if there is little or no blinding on the cliff edge?
Would be most grateful for any advice!

I'm not sure 50mm of MOT is worth anything. Its basically a scattering of stone on the ground. Some individual pieces of aggregate are bigger than 50mm lol.

 

[Dereekoo]

I'm not sure 50mm of MOT is worth anything. Its basically a scattering of stone on the ground. Some individual pieces of aggregate are bigger than 50mm lol.

MOT 1 is 40mm down so any rogue size pieces should be punched level, I assume the blinding is just to give a flat surface for steel fixing purposes but probably not required if ground is flattish , will just be the SE specifying what he always does. Bit confused with the 25cm and 50cm deep descriptions but there should be no vertical blinding as you want the key to be cast against virgin ground

 

[noseall]

Bit confused with the 25cm and 50cm deep descriptions

Sounds like an anti-slip step?

 

[Dereekoo]

Sounds like an anti-slip step?

Not quite sure what you mean by that is it the same as my understanding of shear key

 

[Tangogreen]

 

[Tangogreen]

Thats the drawing. For a 1.6m high retaining wall 1.3m in front of my house. Was an earth before. A lot of steel in there.

 

[freddiemercurystwin]

In reality you would just put a bit of an angle on there instead.

 

[Dereekoo]

Thats the drawing. For a 1.6m high retaining wall 1.3m in front of my house. Was an earth before. A lot of steel in there.

Don't really need blinding with mesh reinforcement, a few suitable sized bits of slab will support it off the virgin ground (better slide resistance) but depends how flat you can dig out ground to, also no issue with the blinding at the cliff face falling away the concrete will fill the void.

 

[^woody^]

The blinding serves no purpose. It's for a different situation, not this one.

 

[stevie888]

Blinding is a thin concrete layer to provide a clean solid surface for steel fixing. It also stops the formation deteriorating if left exposed for a long period. 50 of type 1 would be pretty worthless