Truncate SQL Server Transaction Log file
1. Change the recovery mode from full to simple
2. By using dbcc commands shrink the transaction log file
3. Change back the recovery mode of database to full.
4. Took full backup of database
Note: If log shipping or database mirroring is establish please do not following the above method.
1. Take full backup of database and log file
2. Shrink the transactional log file of the database: