Am I required to offer expiation for an oath after I swore not to go to Quba again on foot, when I had intended by that not to go to a specific and particular place within Quba?

If a person swears an oath not to go to Quba on foot, the oath is based on his intention. If he intended a specific place in Quba, then he does not break his oath unless he goes to that place. However, if he goes to another place in Quba different from what he intended, he does not break his oath, nor is he required to offer expiation. It should be noted that if he intended by his oath not to go to Quba Mosque, then breaking the oath and offering expiation is better, due to the Prophet's ﷺ encouragement to walk to it.