At a wedding the bride encircles the groom 7 times, during Sukkot we circumambulated the alter each day for 7 days, the city of Jericho was encircled for 7 days. Is there an explanation which ties these three things together?
I don't know about 7 days of circling the alter on sukkot. But on the last day of sukkot the alter is circled 7 times that is meant to resemble the 7 circles around the walls of Jericho. And some say that the 7 circles on a wedding is to break the wall between the bride and the groom. So that may be the link between all three. All link back to breaking the walls of "Jericho".
https://en.m.wikipedia.org/wiki/Hakafot Best source other that random sites is wikipedia :)
I have often linked the 7x encirclement of Yericho with the bride's circling the groom.
The chupah is his bay it. Just as Yitzach Avinu consecrated his marriage to Rivka by bringing her to his tent, the groom is doing the same here. But his house has no walls for privacy. Accordingly the bride's circuits are said to create walls between the guest and themselves. But like the 7 circuits around Yericho brought down its walls, the bride's circuits tears down the invisible barrier of negiah which prevented them from physical intimacy.
Another point is that traditionally one who circled the boundaries of land formally acquired the land. So one could say that while the groom "acquired" his bride with a ring, she has acquired him as well!
For a long time I thought this was original to me, but back in the days when his opinion was respected, R. Barry Fruendel told me he uses the same vort.