Board Thread:Support Requests - Getting Started/@comment-11133912-20140725222439/@comment-4784321-20140725224807

Eh no. If you are globally blocked, not disabled, you cannot create a new account to escape your ban. This is called a help:sockpuppet. The user who was globalled banned can appeal via Special:Contact.

If it was a disabled by request, I think you can also Special:Contact, or you can create a new account.

Global blocks can be seen when a user has the "BLOCKED" masthead and there are no logs in their Contributions URL. A disabled can be seen by checking the contributions, a box will appear saying he was disabled.