Does the Catholic Church have a written rule on the depth of a grave in a cemetery?

There is an old saying which goes like this : "A dead man is the landlord of six feet ! " It most probably owes its origin to the custom of burying the dead under six feet of land. I am curious to know if the Catholic Church has a written rule or protocol governing the depth of the grave in a cemetery that a grown-up dead faithful can be buried in.