I don't know about army but in the australian navy the only role not currently open to women is clearance divers, and they're thinking of changing that. I'm not sure why that ban is in place, honestly. Females have been able to be submariners for a while now. Possibly because someone helpfully pointed out the navy that the last time an aussie submariner had physical contact with the enemy was in 1915 so it was hardly a job where one was expected to take a front line role.
And that's with the diesel-electric boats that are specifically designed to work close to shore and opposing ships; the nuclear boats are even further from any direct action.