First I would try chasing and patching, perhaps with wedges, to see if the
settling is historical and not ongoing.

If simple patching does not hold up, then you either have a flawed shell,
or a stress that a correct shell cannot endure, or both.

If the shell is flawed, you must excavate and rebuild it properly.

If unusual stress is the problem, you must also excavate.

http://www.askalanaquestion.com/torque-lock.htm

I really get skeptical of claims like "5000 lbs of torque" when what you
want is linear force, not torque, and when the material strength of
concrete in tension doesn't support but a tiny fraction of such boasted
forces.

I would think you could do just as well with proper excavation, sculpting,
and application of rebar bent into giant "staples" or "stitches", if will,
patched in with premium polymer-modified cement.