Leveling first and then digging trench will destroy the ground leveled before, and digging trench first can be avoided. Of course, preliminary leveling should be carried out before trench excavation to prevent the pipeline from deviating too much.
Pipeline trench backfill is the protective layer of the pipeline, which can stabilize the pipeline and buffer external load and vibration. If the trench is not backfilled in time, it may be damaged by man-made, or floating pipe accidents may occur when it rains.