Hi Lee,
Many years ago I owned a small concrete construction company. 1 time a homeowner had a moving company jack up their house and the old foundation was removed. We set our forms to pour a new foundation. Not a lot of room between the houses on each side. The truck backed in, & when starting to unload, the ground began to give way. The ground knocked over some of our forms. The truck did not tip, and was able to drive out. I and a couple of employees were on the inside of the forms, under the house. Luckily there was an opening on the opposite side for a walkout. A human body can amaze you as to how far apart it is able to make footprints.