It is used to bear the weight handed down from the upper part, and it is the foundation. Only when the foundation is compacted can the building be stable.
Foundation refers to the soil or rock mass that supports the foundation under the building. As a building foundation, the soil layer is divided into rock, gravel soil, sand soil, silt soil, cohesive soil and artificial fill. There are two kinds of foundations: natural foundation and artificial foundation (composite foundation). Natural foundation is a natural soil layer that does not need to be reinforced. Artificial foundation needs artificial reinforcement, such as stone chip cushion, sand cushion and mixed lime soil backfill and compaction.