They put hydrolic jacks on the basement floor to the floor beams of the first floor. once they had it jacked up a few feet then slid these huge beams under the house and jacked it up really high. Then they dug a deep sloped hole toward the house and used big equipment to bang the rocks out of the foundation. They dug out all around and below the house on beams. We had to enter the house by planks , very scary at first and then I decided I could join the circus.
The foundation we put in was pink styrofoam forms and cement in the middle. Really insulates well and we have tubes in the floor so hot water runs thru it. Very nice.