Saturated sub base help - How do i get stone down in this?

[cjh]

I'm intending on block paving my entire front garden and driveway using drivesett tegulas (about 115m2). As I knew the ground was mainly soft soil and clay (plus it will have a large van parked on it) I hired a digger to dig out approx 10-12" below the level I need.

The trouble I'm having is that the ground around here is flat and the water table very high, rain causes grass to be under water and water level under house remains high most of the winter. Now the ground has been dug out its flooding with water. Even if we have not had much rain the ground filling up from the wet soil in the neighbouring gardens and area. If I dig a small hole within 10 minutes it will have water in it. I can't use a soakaway as its clay ground for at least 2m down. I've tried pumping the water and removing soft ground, but the next day the ground is soaked and I'm back to square one. I can't wait for next summer to finish the job. I thought about possibily laying 3-4" deep concrete strips about 2' wide where the wheels run on the drive on the soft ground, then putting stone on top. I have also been advised to remove as much soft clay/sludge as possible then put terram down then stone on top. However not sure if i can get it hard and dry enough for this. Any help or advise would be appreciated. Thank you Chris

[seanandruby]

you will almost certainly need a filter drain. when digging out in those conditions you should if possible leave a surcharge so that the ground doesnt keep getting soaked. then when you have your capping material, dig the surcharge out, lay terran and cover with capping layer. it sounds like a soakaway is out of the question but you need to speak to a local drainage contractor who has knowledge of your area. you may need a geo grid also. hope this helps.

[Tony McC]

One solution I saw recently for just this type of problem was...

Blocks
Laying course
100mm Type 1 sub-base
Terram separation geotextile
200mm Type 3 sub-base
Biaxial geogrid
Sub-grade

...the high void space within the Type 3 allows for water to be accommodated without compromising the structure. The geogrid provides stability for the Type 3 while the separation membrane prevents trickle down from the Type 1.

This is a private access drive with caravan storage in N. Cheshire. The blocks have been down for 4 months and, as far as I know, there's no problem. I'll be looking at it again in the Spring.