An unrealistic excercise

Suppose you drill a narrow tube (with cross sectional area A) from the surface of the earth down to the center. Then line the cylindrical wall of the tube with a frictionless coating. Then fill the tube back up with the dirt (and magma, etc.) you originally removed. What force is necessary at the bottom of the tube of dirt (that is, at the center of the
earth) to hold it up? Let the earth’s radius be R, and assume a uniform mass density ρ.