have you checked to see if the people in your GEDCOM are not already in FS??
keep in mind when you upload to FS - you are not uploading to your own private database - we all are accessing a single shared collaborative database.
so anything you upload - can and will affect the work of others.
and if the people in your GEDCOM are already in FS - you will merely be creating a bunch of duplicates.
As Dennis says (implies), the answer is "yes, but."
It is possible to upload a file to the Genealogies section of FamilySearch. This becomes a searchable but static archive: anybody can look at the data, but nobody (not even you) can change it. (Well, OK, you can change it by deleting the file and uploading a new one.)
Where the major problems come in is when a file uploaded to Genealogies is then used to populate the Family Tree. FamilySearch does offer a tool for this, but it is badly flawed: it generally results in dozens or even hundreds of duplicate profiles, and can blow out years of good research with a single accidental click.
If you want to use FamilySearch as a form of backup for your family tree file, you can upload it by clicking Search at the top of any (non-Communities) FamilySearch page, choosing Genealogies, and scrolling down to the bottom of that page.