Can you prevent a user from commenting on your posts on your Timeline? Yes, you can moderate the commenting by having notifications sent to you. However, when you choose the option to only allow the admin to post to your Timeline, you cannot moderate comments on those posts. So, is there a way to only allow the admin to post on the Timeline and NOT allow users to comment on those posts?
Facebook does not allow you to disallow comments on your Timeline. This article has a quote from a Facebook employee stating:
We think these policy changes support consistency for the Facebook Pages product and encourage an authentic dialogue between people and businesses on Facebook.
Moderation is the only way to accomplish what you seek. An All Facebook article has a better writeup on this (without the quote).