Construction involving prefabricated direct-buried PE-RT insulated piping must strictly adhere to standards such as CJJ 28 and CJJ/T 81. Prior to construction, pipeline routes must be verified and drainage measures implemented to ensure work is performed in a dry trench. For over-excavation depths of 150 mm or less, native soil backfill (compaction ≥90%) is used; for depths exceeding 150 mm, graded sand and gravel (compaction ≥95%) are used. Pipes should be lowered gently using non-metallic slings and laid in a straight line with a minimum slope of 0.002. For pipes with a nominal outer diameter of 63 mm or greater, butt fusion welding is employed at temperatures between 230°C and 250°C, with joints sealed via on-site polyurethane foaming. Pipe ends must be capped at the end of each workday. Backfilling should proceed promptly after the pipeline passes inspection; the trench must be free of standing water and debris. Backfilling must be performed symmetrically in layers from both sides, with each layer thickness not exceeding 200 mm; unilateral backfilling is strictly prohibited. The zone extending from the pipe base to 0.5 m above the pipe crown must be backfilled manually using medium-to-coarse sand or plain soil, free of stones, frozen soil, or other debris. Compaction requirements are as follows: pipe base ≥90%; effective pipe support angle zone and sides of the pipe ≥95%; and the zone within 0.5 m above the pipe crown ≥90%. Mechanical compaction is permitted for the area more than 0.5 m above the pipe crown, with a compaction level of no less than 90% (or as required by site specifications). The minimum soil cover depth is 1.0 m under roadways for motor vehicles and 0.6 m under non-motorized vehicle lanes and sidewalks; protective cover slabs must be installed if these depths cannot be met. Backfilling around valve chambers must be performed symmetrically; unilateral backfilling is strictly prohibited. Voids left after the extraction of steel sheet piles must be promptly filled with sand and compacted. Standardized construction practices ensure the safe operation of the pipeline and the long-term stability of the heating system.