砂卵石地质河流大开挖双管穿越施工技术

large Excavation Construction Technique for Double Pipeline Crossing River in Geological Condition of Sandy Gravel

中缅油气管道工程国内段瑞丽江穿越工程,由于河流冲刷线深,河床为砂卵石地质,土质松软易塌方,河床渗透系数高,渗水量大等原因,给河流大开挖穿越施工带来了极大的困难。采用钢板桩半幅围堰方式,在国内首次成功实现了大开挖双管穿越瑞丽江砂卵石地质大型河流。在介绍了工程概况的基础上,详细论述了穿越现场情况,开挖试验,施工方案的制订,施工流程,半幅围堰结构,钢板桩施工,抽排水,管沟开挖,管道安装、检测、防腐,管道试压,管道稳管、回填、连头等内容,最后给出了钢板桩围堰施工的实际效果和优缺点。

China-Burma Petroleum Pipeline crosses Ruili River where there are deep scouring, geological condition of sandy gravel, easily coilapsible loose soil, high permeable coefficient of riverbed and large seepage. These factors made the excavation construction of river crossing great difficult. The method using steel sheet piles to form half width cofferdam was applied and it realized the double pipelines crossing Ruili River. This paper describes in detail the project site condition, excavation test, construction plan, construction procedures, structure of half width cofferdam, construction of steel sheet piles, water drawing and drainage, trenching, pipeline installation, inspection, anticorrosion, pipeline pres- sure test, pipeline stability, soil refilling and pipeline joints. Then it presents the construction results and merits and de- merits of the method using steel sheet piles to form half width cofferdam.