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.

Low - density turbidity current is a transition flow evolved from gravity flow to drag flow,whose supporting mechanism and transporting way of the sedimentary grains have different characteristics in the different stages of sedimentary evolution process, so the mineral components, grain sizes, sorting characteristic, depositional textures,etc.