Covered Trench for pipes + utilities?

[unclebob1]

Hi All,

Not sure which area of the forum this goes in as it covers multiple areas, but I've put it in here as the one I think fits best!

I have a walkway (my own) down the side of the house - approx 1m wide, for the full length of the house.

At present, my sewage runs from the side of the house towards an existing manhole.
My rain water runs from the back of the house, away from the existing manhole (i.e opposite direction to the sewage)

I have a gas main coming to the front.

Eventually I want my electric and water pipes to also come down this area + I want to add a new rainwater downpipe to the front of the house + keep the existing.

From what I can tell, the current path is just a concrete slab on some building rubble, and probably clay underneath.

I want to create a wide U channel - say 50 cm wide and same deep from the front to the back, and then run all the pipe work in there- So Sewage + grey water, rain water, fresh water, gas, mains electricity + SWA for an outhouse in the future etc.

I am thinking of then capping over the top with slabs leaving 3-4 manholes for access to key joints. Weight for access (diggers etc) wont be an issue as I have another point of access directly into the garden without going over this area.

Are there any regs or issues with combining these services like this? with all the utilities running in the same concrete channel? Note to be clear I will not be moving/changing/altering any of the existing GAS work - I'll work around it. The waste+ rain water will be replaced. Power and water are not currently run from here, but if I upgraded to 3phase in the future then this would be the easiest route to bring it in. Mains water is more when I redo driveway I can run in the pipe for the future (my existing is 25mm poly blue so not likely to change)

Rough sketch is attached.

 

[Tigercubrider]

I don't know but...

Where I work they use similar set ups. However, there could be rules about separation of services.
You'd need to ensure that you reach the minimum depth to suit the most demanding of the services.

 

[oldbutnotdead]

Water and electricity want to go good and deep- water to stay below frostline, electricity to stay below pickaxe range. Sewage is dictated by the depth of the connection to the public sewer. My garage trench has water, power (swa) and ducting for Comms 1000 below ground, backfilled with sand, marker tape, sand, marker tape, bricks, marker tape. Waste shares the same trench, only about 250 below ground cos that's where the falls dictated it went.

 

[unclebob1]

I'm hoping to not backfill - instead create a slab over the top so in effect it becomes a tunnel, Happily insulate over the water pipe etc to keep it away from the colder days