Record Setting 3,300-m Distance by Horizontal Directional Drilling of a 711-mm-Diameter Pipeline Crossing the Yangtze River

This paper describes a record setting project in the horizontal directional drilling field involving twin pipes with a diameter of 711 mm and a length of 3,300 m. The Yangtze River is the longest river in China. The Jiangdu-Rudong gas pipeline, which is part of the Chinese gas pipeline trunk network, was constructed to transport gas from the north side to the south side of the River. The width of the river surface is 3,000 m, and the length of the crossing is 3,300 m. It was recommended by engineers that twin pipes with a diameter of 711 mm be used instead of the existing pipe with a diameter of 1,016 mm. The required depth of penetration for the crossing was determined by an analysis of 43 years of historical river scour data from 1966 to 2009 combined with a calculated result using a river scour depth formula. The recommended construction scheme included arranging two drilling rigs, laying magnetic-signal submarine cable, using the intersect method, and designing a new flat-barrel combination-type reamer. This major project was finished successfully on July 27, 2013.