We all know that the northeast is seriously damaged by freezing, and the ground is always deformed by freezing. So after determining the survival elevation, at least 30 cm of soil should be dug. After tamping the ground, the next step must not be to cut corners, that is, to lay at least 5 cm of grit and 5 cm of gravel. This is because there is a lot of water in the soil, which will expand after freezing. Gravel cushion plays a buffering role to prevent hardening and freezing. In order to harden and keep the shape unchanged, we need to lay double-layer bidirectional steel bars, and then lay 12 to 15 cm of concrete. Seven days of health is enough.