针对山区段管道施工中存在的主要问题，并根据管道施工安全和质量保证体系的要求，提出了平原地段管道实行沟上焊接，山区地段管道全部采用沟下焊接的施工方案。

To accord with the safety and the quality insurance system in pipeline construction, a new construction scenario, the welding over ditch in plain area and welding in ditch in mountain...

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