Cushion refers to the structural layer below the base. Its main functions are waterproof, drainage and anti-freezing, so as to improve the working conditions of grass-roots and soil foundations and require their water stability.
Cushion is located in the structural layer between foundation and soil foundation. When the water stability of soil foundation is not good, it is used to improve the water stability of soil foundation, improve the water stability and frost heaving resistance of pavement structure, disperse the load and reduce the deformation of soil foundation. Therefore, it is generally set when the soil base is wet and the temperature is not good. The strength requirement of cushion material is not necessarily high, but its water stability must be good.
Concrete cushion is the intermediate layer between reinforced concrete foundation and foundation soil. Its function is to make its surface smooth, which is convenient for binding steel bars on it, and also plays a role in protecting the foundation. It's all plain concrete, not reinforced. If there are steel bars, it can't be called cushion, but should be regarded as foundation slab. Protective layer of reinforced concrete foundation: 40mm when there is buffer; 70mm without cushion.
Cushion thickness Section 8.2 of Code for Design of Building Foundations (GB50007—2002) stipulates that the cushion thickness of the extended foundation shall not be less than 70mm, and the strength grade of the cushion concrete shall be C 10.
What's the difference between foundation and cushion?
1, foundation and cushion have different meanings.
The foundation is a component used to bear the load of the superstructure, and the cushion is a layer of plain concrete cushion laid under the foundation to facilitate the construction of foundation concrete and protect the reinforcement of foundation concrete.
2. The use parts of foundation and cushion are different.
The foundation cushion is located underground, so the construction is difficult. However, some foundation cushions will have a large area and can be constructed by roller machinery, while the ground cushion in the building will use different parts from the foundation, which leads to different construction conditions.
3. Play different functions.
Cushion is the intermediate layer between foundation and foundation soil, and its function is to protect foundation. The foundation is a load-bearing structural layer.
The foundation bears all the load of the house, so the foundation should have enough strength to transfer the load to the foundation stably, and the foundation should meet the durability requirements. If the foundation is destroyed before the superstructure, it is very difficult to check and strengthen, which will also affect the service life of the building.