Trench backfilling is the last process to ensure the burial depth of long-distance pipelines, and is also an important factor in ensuring pipeline installation quality and operational safety. Generally, the trench backfilling work is required to be completed within 10 days after the pipeline is laid into the trench. The trench backfilling requirements for different types of pipe sections are also different. The stone section trenches should first be backfilled with fine soil to 300mm above the top of the pipe. The maximum particle size of the fine soil should be The diameter should not exceed 10mm, and then backfill the original earth and stone. The maximum particle size of the stone should not exceed 250mm; the fine soil of the pipe trench in the Gobi section can be backfilled to 100mm above the top of the pipe, and the maximum particle size of the fine soil should not exceed 20mm; the pipe trench in the steep slope section should be backfilled with bags The soil should be backfilled in sections; the pipe ditches in the basic farmland areas should be backfilled in layers, with the surface cultivated soil placed on the top layer so that surface vegetation can be restored as soon as possible. After that comes the landform restoration and project acceptance.
