Huanggang Port Area Iron and Water Combined Transport, Pipe Matching Wharf Water Supply and Drainage Pre-embedded Pipeline Construction

In the railway-water combined transportation project in Huanggang Port Area, the construction of the water supply and drainage pre-embedded pipeline of the pipe supporting terminal is the "underground artery" to ensure the operation of the port area. This area is close to the Yangtze River, the groundwater level is high, and the terminal yard will bear heavy container loads in the future, which puts forward strict requirements for the backfill compactness of the pipe trench and the stiffness of the pipeline ring.

The construction team first accurately laid out the line, using mechanical excavation to reserve a protective layer above the design elevation, and then manually cleared the bottom to avoid disturbing the original foundation. In terms of material selection, the water supply main pipe adopts polyethylene pipe with reliable pressure bearing capacity, and its flexible interface can effectively absorb the uneven settlement between the wharf trestle and the land storage yard; the drainage buried pipe adopts large-diameter structural wall polyethylene winding pipe, the inner wall is smooth, resistant to initialization, and the elastic modulus is suitable for deep burial needs.

Pipe connection is the core of quality control. The polyethylene pipe adopts hot-melt docking, and a windproof and dust-proof shed is set up on the working surface. The heating temperature and heat absorption time are strictly controlled to ensure that the tensile strength of the interface is not lower than that of the base material. After each section of pipe is laid, the elevation is re-tested in time, and the joints are extracted according to the standard frequency for appearance inspection and water pressure test.

Before the closed water test, the two sides of the pipe and a certain range above the top of the pipe are backfilled with sand and gravel and rammed symmetrically. After the top of the pipe reaches a safe thickness, the hydrostatic pressure test with the base can be carried out to closely monitor the leakage. The drainage sand content in the port area is large, so a sediment grille is specially added at the access of the inspection well to prevent silting.

The backfill operation is layered and rolled, and the lime-soil improved backfill is used in the heavy-duty area at the front of the wharf, and the compaction degree is increased to more than 95% of the heavy-duty compaction standard. Before the completion and acceptance of the whole line of pre-buried pipelines, endoscopic video inspection was also carried out to check the interface misalignment and foreign objects in the pipeline one by one, which laid a solid foundation for the long-term water supply and drainage system of the Huanggang Port Area Railway-Water Intermodal Transport Hub.