10+caster level+casting stat it looks like from the spell description.
It is poorly explained. You can by spell description grapple, but how to break the grapple is not detailed, but working with the logic of the spell:
Combat Maneuver: Alternatively, once per round, you can use telekinesis to perform a bull rush, disarm, grapple (including pin), or trip. Resolve these attempts as normal, except that they don't provoke attacks of opportunity, you use your caster level in place of your Combat Maneuver Bonus, and you add your Intelligence modifier (if a wizard) or Charisma modifier (if a sorcerer) in place of your Strength or Dexterity modifier. No save is allowed against these attempts, but spell resistance applies normally. This version of the spell can last 1 round per caster level, but it ends if you cease concentration.
So, I figure since you use CL for BA, and casting attribute modifier instead of str or dex, the CMD is CL + 10 + int (replace str)+ int(replace dex). So 10 + CL + 2x int modifier.
Otherwise, you could imply that by RAW that there is no CMD, and therefore cannot break the grapples or pins while the spell persists. That is something I personally wouldn't promote.
It is poorly explained. You can by spell description grapple, but how to break the grapple is not detailed, but working with the logic of the spell:
Combat Maneuver: Alternatively, once per round, you can use telekinesis to perform a bull rush, disarm, grapple (including pin), or trip. Resolve these attempts as normal, except that they don't provoke attacks of opportunity, you use your caster level in place of your Combat Maneuver Bonus, and you add your Intelligence modifier (if a wizard) or Charisma modifier (if a sorcerer) in place of your Strength or Dexterity modifier. No save is allowed against these attempts, but spell resistance applies normally. This version of the spell can last 1 round per caster level, but it ends if you cease concentration.
So, I figure since you use CL for BA, and casting attribute modifier instead of str or dex, the CMD is CL + 10 + int (replace str)+ int(replace dex). So 10 + CL + 2x int modifier.
Otherwise, you could imply that by RAW that there is no CMD, and therefore cannot break the grapples or pins while the spell persists. That is something I personally wouldn't promote.
Umm I'd go with something along the escape grapple DC for Black Tentacles:
"The CMD of black tentacles, for the purposes of escaping the grapple, is equal to 10 + its CMB."
Applying Int twice seems weird.