The gas pipeline is generally very long, and should be divided into sections and pipelining, that is, according to the construction force, reasonable arrangement, divided construction, pipe trench excavation, immediately install the pipeline, at the same time excavation of the next section of pipe trench. Complete a section, immediately backfill pipe trench, avoid long distance pipe trench long-term exposure caused by the impact of traffic, safety accidents, pipe mouth corrosion, corrosion layer damage, ground water (or rain) into the pipe trench caused by trench wall collapse, trench bottom subsidence, pipe sinking or floating, water in the pipe, pipe wall corrosion and other accidents.