It seems every instance we have the word סביב in the Torah, Targum Onkelos translates it as סחור סחור, a doubling of the word which I would have assumed would suffice in single format. See for instance Bereishis 23 17, Shmos 19 12, Vayikra 1 5, Bamidbar 34 12. I could go on, but I won't.
A)Why is this?
B)When a different version of the word is presented we find various choices of words in Targum Onkelos, but none doubled. We find סובב meaning surrounding, and a singular translation of מקיף is given. See Bereishis 2 11 & 13. See also there 37 7 תסבינה is מסתחרן in Targum Onkelos, a singular version of סחור. The same is in Bamidbar 34 4 & 5 ונסב is ויסחר.
What is the mechanics behind this?
Finally, what was חז׳ל's intention when doubling the word סחור in order to emphasise the turning away? See for instance Shabbos 13a דאמר עולא אפי' שום קורבה אסור משום לך לך אמרי נזירא סחור סחור לכרמא לא תקרב.
If the phrase סחור סחור is in fact the standard Aramaic rendering of סביב as we seem to find in Targum Onkelos, than that doubling does not mean to be extra careful to turn away, so why use that phrase in conjunction with לך לך and in a sentence which seems to imply extra care to stay away?