Is it possible that the Universe is expanding due to additional Big Bang events? Is it theoretically possible that the Universe is expanding due to additional Big Bang events that have occurred at the same location that the original Big Bang occurred at?

Perhaps there has been an ongoing series of smaller Big Bang events over the past 13.7 billion years, which although were not as massive in scale as the original Big Bang, have created a large amount of new space-time and new matter that has resulted in the Universe expanding.
You may need to revisit the theory behind the Big Bang. The Big Bang is more or less a description of what the early universe looks like if you view expansion in reverse. The single "Big Bang" at the beginning of our universe is the only "Big Bang" event predicted by expansion. Also, the Big Bang did not happen in a single place, it happened everywhere in the universe. Finally, the Big Bang did not create space-time, and the expansion of the universe is not the creation of new matter. The Big Bang describes a time when the metric of space-time was extremely dense, and expansion is the metric of space-time increasing as below:



The distance between points in space increases, but the same mass-energy is there as before.