Taking the pipeline crossing Hanjiang river in Zhongxian to Wuhan nature gas pipeline project as an example and according to the geological and hydrologic conditions, this paper describes the main techniques of pipeline bottom-towing method, including ditch excavation and survey, buoy design, towing force calculation, steel wire selection.

Object: Traction therapy to explore the technical PLDD Whether or not there is the role of the early effect and its mechanism, so as to further improve clinical efficacy.