CP using prefab concrete. I have done this all my life. You can pour onsite and lift them up into position. The system was originally designed to be done without a crane. We have done in areas that are so remote that if you can drive to your property then you are still in suburbia. One of my first experiences sharing my expertise was a group of five couples that built all their walls and installed them with chain block on a little mobile gantry. We made tiltup walls using river shingle and lifted them with a backhoe. Think outside the box.

My brother in law has two fire bunkers on his property using 2.4M concrete well liners, Has not had to use them but has done fire drills with them.