I have recently started digging and laying the base for a patio with pavers. Its roughly 300 sqft and the soil is made of clay. I dug around 7" deep to have 4" gravel layer, 1" sand an 2" for the pavers and noticed that after compacting (using a plate compactor) the clay and the 4" gravel on top there are a couple of spots that are roughly 2×2 ft that act as a liquid when I step on them. I think its called "liquefaction". There was quite a bit of water in the clay due to a few days of rain but no standing water.
I do not want to lay anything on top until I stabilize it and wanted to get an opinion on whether its just a matter of drying it, or whether it's ok to proceed and it will harder or settler, or if I can add something to give it more stability.
P.S. the gravel is "A" type gravel, and the rest of the patio space is extremely rigid except the two spots.
Thank you!
Best Answer
You’ll continue to have that “liquid” action until you remove the water.
I’d provide a way for the water to “runoff”, like a perimeter drain, drain rock at the perimeter, etc. that will remove the excess liquid. (I’d make sure the drainpipe extends to a ditch or something, to carry the water away. Water will run in the direction of least resistance.)
Your Class A gravel will give you a good base and the sand will provide a layer for you to set the bricks level, but I’d provide a filter fabric between the sand and the gravel. Otherwise, the fines in the sand will “wash” down into the gravel and the bricks will soon be uneven.