1. Pre-embedded fixing of water collector: fix the water collector with concrete reinforcement on the bottom die and pour concrete. 2. Water-closing test of caisson structure: intercept a section of drainage pipe with a length greater than the height of caisson, insert the drainage pipe into the socket of casing without gluing, seal the outer diameter of the pipe tightly with the casing wall as the nozzle, and pull out the blocked drainage pipe for drainage after the caisson is closed. 3. Open caisson cleaning and leveling layer construction: Before open caisson leveling, clean the base, treat the internal corner with an R angle, make an arc with a radius of r=50mm at the internal corner with mortar, find the position of the embedded water collector in the positive slope direction, pay attention to the finished product protection of the water collector, and prevent the mortar from polluting or blocking the water collector. 4. Waterproof construction of caisson: Waterproof construction shall be carried out according to the design drawings, and the position of water receiver shall be specifically strengthened. 5. Installation of riser: First, install the middle-level connector on the water collector and rotate to adjust the axial position of the middle-level connector, then install the inner-level main pipe connector and rotate the axial position of the inner-level main pipe. 6. Secondary water closing test of caisson: Before the secondary water closing test, rubber strip should be used to plug the holes in the water collector. After the closed water test is completed, rubber strip can be pumped out for drainage. 7. Masonry of tube well: the riser is closed by masonry, and a hole is left at the bottom. Pay attention to the default lintel above the hole. 8. Branch pipe installation: When installing branch pipes, ramps must be set according to the design requirements and fixed firmly. 9. ceramsite filling: according to the design requirements, fill the caisson with ceramsite to the design elevation, then level it with cement mortar and coat it with waterproof membrane. 10, floor tile paving: finally, the floor tile is paved according to the design requirements.