High-Risk, 610 mm Diameter, 2,090 m HDD Project—A Case Study

Lanzhou-Zhengzhou-Changsha Pipeline Project, which supplies the product oil to two areas covering Hubei and Hunan provinces from the area at least 3,000 km away, crosses Yangtze River in Wuhan, Hubei province with pipe diameter of 610mm and length of 2,090m for crossing. The elevation difference between the lowest point and entry point is up to 75m. For this project, the main formation in crossing section is conglomerate and glutenite. As the conglomerate is very hard, of which the compression strength can be up to 59.7MPa, while the glutenite is easily broken, of which the minimum compressive strength only is 0.13MPa. The frequently changes of hard and soft due to the staggered distribution of conglomerate and gluenite and also the 12 fracture zones there makes the geology extremely complicated and the risk during the construction very high. Thus, this project is one of the most difficult horizontal directional drilling (HDD) crossing projects in the world. This paper is going to introduce the details of the troubles encountered during this HDD crossing project and the solutions from the design stage to construction, so as to provide experience and knowledge for the design and construction of such kind project.