大口径管道定向钻对穿工程设计优化与施工

The optimized design and construction of the opposite-direction crossing for HDD pipeline

西气东输二线泾阳泾河穿越是目前我国管径最大的管道长距离定向钻对穿工程,穿越地层主要为卵石层、粉砂层及粉质黏土层。在φ1219大口径钢管穿越设计中采用"大开挖深基坑埋管+长距离夯套管+定向钻对穿"的组合穿越方案,并在施工中实现了优化扩孔器组合、调整泥浆性能、使用推管机协助管道回拖等多种技术创新,成功解决了两岸厚卵砾石层穿越,河床高硬塑性粉质粘土层扩孔时卡钻、抱钻以及管道回拖卡管等施工技术难题,可供类似管径定向钻穿越工程参考。

The Jing River crossing project is the biggest pipe diameter and long-distance directional HDD opposite-direction pipeline crossing engineering in China.The crossed strata mainly contain cobble layer,silt sand layer and silt clay layer.The combination crossing program of 'heavy excavation of deep foundation pit to lay pipe+long-distance raming cannula+HDD opposite-directional crossing' was adopted for φ1219 pipe crossing design.And also,many kinds of innovated construction technologies such as the optimization of reamer's combination,modif ication of the mud property and application of pipe pusher to tow back the pipeline were used in this crossing project.Lots of difficulties were solved successfully in traversing the pebble layer of riverbank,the aiguille blocking or clasping in the highly hard-plastic silty clay layer and the pipe locking in the towback.All of those were useful to similar pipe diameter directional drilling crossing project.