To archive a survey navigate to 'Surveys' > 'View'. From here click the 'Archive' button as shown below:
From here you'll see the following message:
If you're sure you'd like to archive a survey click 'OK' or otherwise click 'Cancel' to opt out.
A word of warning, Archiving a survey means that you can no longer find it. So be sure that you want to archive a survey before you do so.