Luoyang-Zhumadian oil product pipeline of Yellow River crossing project is the Key project of the line from Luoyang Co. SINOPEC to Zhumadian oil depot. The project located at the river bed of the mid part of Yellow river with very complex geological conditions, such as the high water pressure, quicksand and cobbles, and the crossing distance is 1700m with 355mm pipeline diameter. The most difficulty is to cross the cobble layers of the thickness 25m and 40m, with cobble diameters from 20-70mm to 70-140mm, or even up to 600mm of the most. This project is regarded as the most difficult one in HDD crossing history ever since.
In the project, HY used the self-developed DG-800 pipe-jacking machine which can jack the long casing into the cobble layer so as to shelter the drill stirring for the pilot hole making, accompanied with the drill bits interfacing technology to complete the pilot hole as well as the pull-back stage smoothly. The technical problems like uneasy to keep the drilling hole in the cobble layer, mud leaking etc were successfully cleared.This project is the milestone of the HDD crossing which solved the worldwide problem for the crossing through the cobble layer.