If it's ideas you want this may help you get thinking.
Spotted this on the net. -G
How to Keep Landscape Rocks from Sinking
Larger rocks will naturally settle over timethis is normal. But if it begins to upset the aesthetic, youll want to deal with it as soon as possible. If you fail to deal with this problem, it becomes very challenging to sort out. The deeper the installation sinks, the greater the chance of stains and the more difficult it is to retrieve later.
The reason this usually happens is due to a soft foundation like grass or soft soil. You may combat this issue by:
Spreading out the load a little may help, although it will change the aesthetic. ( I'm sure this is for a bunch of smaller rocks)
Laying a layer of gravel beneath larger pieces provides a firm foundation that prevents subsidence.
Compacting the earth before the installation is expensive but produces long-lasting results. Compacting helps remove small air pockets that will, in time, compact from the weight of the installation.
Applying foundation fabric may also prove helpful as it provides a more secure base. The stiffness of the polyester or linen fabric prevents the rock from sinking deeper into the soil.
In our area we have heavy clay soil and my lot is covered in boulders that have been there since the ice age Id say. Clay does not absorb much water at all, these boulders are sunk maybe 6 inches. If you clear say 1 acre, youd find hundreds of natural roundish boulders. Some are 10-20 ft across, not on my lot but if I drive 2 or 3 miles I see maybe 20 or so big ones that have been in the same place thousands of years. If you dig a hole around here, you can go down as far as you want- just watch The Oak Island Treasure Hunt, they are 7 miles from me and have been down 200 ft or so. :)
If you have clay soil, I wouldnt worry about a rock that big sinking much. But I dont know your soil.
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63 Parisienne sport coupe (The Big GTO), black, maroon interior, 409 4 speed; former owner of a 59 El Camino, 63 Corvette SWC, 62 Chev Bel Air SC. 1963- Pontiac top selling car in Canada
Mahone Bay, NS Still not old enough to need an automatic
