Welcome to the forum.
You have two problems now. One is that the trash will take forever to empty, the other is that you have probably destroyed the Time Machine backup if you used Finder to move those 77 backups to the trash. Although you can see the files in Finder on the TM backup drive, they are mostly not really files, but links to where the files really are. Without going into the details on how TM works, the simplest way at this point to gain control of your system is to cancel the trashcan empty process, wait for it to stop (It will take some time to do that), then just use Disk Utility to erase the entire TM drive and start over. If you use Finder to delete backups, that process breaks the chains of links TM uses to keep track of the various backups. Even if the Trash emptying process finishes, the TB backup will have lost integrity and no longer be of much value, so just starting over is the best way to go.
Now, if you have anything other than TM files on the backup drive, you have two choices--wait for the trash empty process to finish or erase the drive and lose all of those other files on the drive along with TM.
Sorry for the harsh news, but it's where you are.
