天然气海底管道底穿输水管道施工技术

Construction Technology for Submarine Gas Pipeline Crossing Beneath Water Pipeline

为防止海流冲刷、保证海底管道的稳定,避免船舶抛锚和渔船捕鱼对海底管道造成损害,埋设海底管道时通常有埋深要求。海底管道与其他管道交叉时,通常采用上穿方式跨越其他管道,同时采取保护措施。在一些特殊情况下,为确保当地唯一输水管道和航线通航安全,降低工程对附近海堤、港口及码头的影响,海底管道采取底穿海底输水管道的方式。施工过程中制定特殊的打钢板桩工艺对输水管道进行加固防护,再进行管沟预开挖,管道穿越采用浮拖与底拖穿越结合方式,最后进行管道的回填交叉防护。文章以甬台温工程龙湾电厂支线成功实施底穿为例,介绍了海底管道底穿输水管道的施工方法以及可采取的一些技术措施。

In order to prevent seawater from scouring subsea pipeline,ensure its stability and avoid such operation as anchoring and fishing from damaging pipeline,installation of subsea pipeline shall meet relative burial depth requirements.When a subsea pipeline crosses another one pipeline,it crosses above that pipeline usually and some protective measures will be taken.In some special cases,in order to ensure the safety of local water pipeline and ship navigation and reduce effect of pipeline installation operation on nearby seawall,port and dock,the subsea pipeline shall be installed through such manner as crossing under the water pipeline.Before installation operation,special steal sheet piles shall be used for reinforcement protection of the water pipeline at first and then pre-excavation of gas pipeline trench can be conducted.Such manner as buoyant tow in combination with bottom tow shall be applied for gas pipeline crossing under the water pipeline and backfilling shall be done for better protection of the two pipelines.Taken successful implementation of Longwan Power Plant branch line in Yong-Tai-Wen Project as an example,introduced are the feasible construction method and technologies of the subsea pipeline crossing under water pipeline,which will provide valuable reference for similar projects.