I am putting in a mini split system (either Mr Cool or Mitsubishi) this summer.  One of the challenges I face is locating the main unit.  I don't want to hang it on the house as I have read too many people complain about the vibration noise no matter what they do.  So, I want to make a pad for it on the ground.  However, we have a very, very heavy clay soil.  Like almost all clay.  And we have a fair amount of soil creep.  So I am concerned that after a few years, some stress might be placed on the connections were I simply to do a standard pad.  I was thinking of sinking some anchor rods into the ground, say 4-6 feet long to help anchor the pad.  Is this a good idea, or is there something else I might do to address the clay soil?  Thanks in advance.