On some occasions when we couldn't dig that deep for various reasons, water table, large rocks etc, we would pile the soil up around the grave so it looked deeper.
we also would remove remains from graves if the first coffin was buried at 4ft and another was going in on the top, shouldn't have happened but it did, we would put remains in a tarp or bags and put them back in again after the funeral, we always got an extra tip for those jobs as it was and is highly illegal.