Compaction construction method of lower arc position of sandy soil basement drain pipe

The invention discloses a compaction construction method of a lower arc position of a sandy soil basement drain pipe. The method includes the following steps of laying the drain pipe for a closed-water test; laying a drain pipeline on a pipe ditch central line, conducting a closed-water test on the drain pipeline, and conducting pipe ditch backfill work after the closed-water test is qualified; conducting layered backfill sand laying and cofferdam forming; mechanically or manually putting sandy soil to the two sides of a pipeline in a ditch, and manually spreading sandy soil to be uniform; building a cofferdam 300 mm wide and 300 mm high every 10 mm, and conducting water injecting; conducting water injecting work on the two sides of the drain pipe at the same time after a sandy layer is laid completely; conducting grinding through a spike grinder, and conducting sand compensating, wherein grinding is conducted through the spike grinder, the number of grinding times is not smaller than 8, and the lap joint wid