It depends on what foundation the house is built on. If it is a level, it will be tamped with concrete. 100 thick high-grade concrete can be reused.
If you are in a mountainous area, such as Chongqing or Sichuan, you should clean up the floating soil and build the land on rocks. It would be better to put on anchor piles. Although it costs a lot, there is no natural disaster of landslide.
If you are in the mid-levels or hilly areas, you should avoid the places where rainwater collects, and choose places where the soil is not too thick as the foundation, and it is best to play reinforced concrete ground beams. Not too expensive.
If it is a well-built house, it will be more difficult and more expensive to strengthen the foundation. Drill holes in the ground, and insert steel cables for grouting. Ordinary houses do not need such advanced technical means, and folding and reconstruction are cheaper.