Construction method for laying drainage pipe network at upper portion of basement in excavation-free mode

The invention discloses a construction method for laying a drainage pipe network on the upper portion of a basement in an excavation-free mode. According to a drainage pipe network design drawing, measurement and setting-out are conducted on the position of a pipeline, pipeline groove walls are built, the distance between the walls is 100 mm larger than the outer diameter of the pipeline, and the height of the tops of the walls is flush with the horizontal center line of the pipeline; a sand cushion layer is backfilled in pipeline grooves, the slope of the laid pipeline is controlled while backfilling elevation is carried out, a steel bar anchoring ring is pre-buried on the outer side of the pipeline groove walls, the pipeline is laid in the pipeline grooves and located on the sand cushion layer, and an iron wire is tied and fixed to the steel bar anchoring ring from the upper portion of the pipeline for fixing the pipeline; and earthwork backfilling is conducted on a basement roof according to the designed s