1965 concrete garage floor - Hardcore Below

[Stupida]

I dug a channel in my 55 year old garage floor for 110 soil pipe and noticed the hardcore underneath is just old house bricks (whole and half) as well as general building rubbish. It also seems that its sunk down as I can reach under the slab a little next to the cut.

Is there anything that needs doing or is this normal?

 

[Murdochcat]

Why are you digging to add a soil pipe? Garages of this age were built in unconventional manners to say the least

 

[noseall]

Is there anything that needs doing or is this normal?

Poor compacting/laying. Very common back in the day. Try and ram as much back as you can, without removing all the skin from your knuckles.

 

[Stupida]

Thank you for the advice Noseall.
The back end of the garage is going to be a shower room