Foundation pit deep well rainfall and plugging construction method

The invention provides a foundation pit deep well rainfall and plugging construction method, and relates to the technical field of building construction. A graded broken stone layer is laid at the bottom of prefabricated reinforced concrete sunken pipes, a steel plate is arranged on the upper end faces of the prefabricated reinforced concrete sunken pipes in a sealed mode, a through hole is preformed in the center of the steel plate, a galvanized steel pipe with the lower end stretching into the graded broken stone layer is inserted into the through hole of the steel plate in a penetrating mode, and the galvanized steel pipe on the steel plate is connected with a water suction pump for water suction. After waterproof construction is conducted at the bottom of the upper section of a deep well, bottom plate reinforced concrete pouring is conducted on the waterproof construction face. After the water suction pump is located at low water pressure, a valve is closed, the galvanized steel pipe located above the valve is cut off, and a building backfill layer is constructed to the upper end face of the galvanized steel pipe. The construction period is saved, investment of labor and material resources is reduced, the water leakage phenomenon generated after basement bottom plate structure construction is avoided, and cost consumed by plugging through various measures due to water leakage of a basement bottom plate is reduced.