As far as we know, there's no direct connection between the two events.
In "The Big Bang", something has forced the TARDIS to a specific point in time -- something directly relevant to Amy's wedding -- and caused it to explode. We know the Silence are supposedly to blame for this, but as of yet we have no idea how they pulled it off. This explosion "really happened", but The Doctor was able to reverse it's effects by using the Pandorica itself. In particular, the cracks in the universe existed before the explosion (rippling back in time), but closed naturally afterwards.
On the other hand, in "Journey to the Centre of the TARDIS", we know why the TARDIS is in danger of exploding: the salvage crew has somehow damaged it and compromised the security of it's fuel containment system. There's no indication that the Silence had anything to do with it. It has no apparent connection to Amy Pond, and there was no mention of cracks in the wall. In addition, The Doctor was able to undo this explosion "locally" -- causing a paradox that reset time a few days, as opposed to having to reboot the entire universe.
The possibility of the TARDIS exploding is a pretty generic "danger". There doesn't seem to be any reason to expect all such incidents to be connected to each other.