Those drains again - When is it safe to whack

[AndiForest]

Hi again

Plastic drains and block paving.

My drains have proven to be a problem, more so because of my lack of know how and confidence. On my previous post there is a pic of the problem. I have two questions.
Although for foot traffic and pulling a trailer over, because of the lack of depth for sub base, I am inclined to look at casting a concrete slab across the pipes to a height for sand and blocks. I was thinking about doing this when I run the brick course along the side of the house. Does this sound ok?

Further down as the drain drops the depth increases sufficiently to allow for sub base etc. Is it ok to run a compactor over the shingle that covers the drain when compacting the sub base? I have to build up the level of sub base by 200mm so the drain will be a minimum of 300mm below top of sub base. I hope this makes sense.

Cheers for any advice.

[Dave_L]

Yep, you'll be fine - I take it you'll be using a plate compactor?

We usually use a ped roller - you have to be a little careful of shallow pipework with those.