Construction technology of large diameter HDPE hollow wall winding pipe

What is the construction process of large-diameter HDPE hollow wall winding pipe?

HDPE hollow wall winding pipe is a flexible interface, which has the characteristics of light weight, no need to make pipeline concrete foundation, and can shorten the construction period. During the construction, according to the characteristics of large diameter pipe interface stress, interface leakage, HDPE material thermal expansion coefficient, pipe mouth deformation and other new pipe performance, deep pipe trench digging, abundant groundwater and other environmental conditions, adopted the internal and external thermal shrinkage belt sealing, external electric hot melt belt connection sealing, pipeline ground splicing, the overall lifting construction scheme. The influence of groundwater on the interface process is reduced, and the construction schedule and installation quality are ensured.

Trench excavation: The deepest excavation of the pipe trench is 4m, the soil condition is poor, and the groundwater level is high. The pipe base is rammed and smooth according to the stratified combined trench excavation, the sand layer of 200mm is laid, the contact area between the bottom of the pipe and the foundation is increased, and the pipeline is protected.

Interface connection mode: HDPE hollow-wall winding pipe, the pipe interface inside and outside the use of heat shrinkable tape bonding seal, external electric hot melt fixed tape connection, to ensure the interface tightness and sufficient connection strength.

Ground splicing: Place the pipe in the flat part of the pipe ditch side along the pipe ditch, and cut the corresponding length according to the distance between the two Wells. The pipe can be cut with a woodworking saw, and the end of the pipe can be smoothed with a woodworking plane. The operation pit is dug 300mm deep under the connection part of the pipeline, and the operation pit is 200mm specific to the electric melting bandwidth.

Heat shrinkable belt connection: The pipeline is leveling and aligned, requiring that the pipeline is horizontally aligned, the relative offset of the center line between the two pipelines is not greater than 7mm, and the opposite gap is not greater than 10mm

① Prepare gas heating device: liquefied steam tank, hose and spray gun.
② Clean the connection parts of the pipe, and there is no mud sand dust within 800mm of the pipe end.
③ The connection part of the pipeline should be evenly heated to 80~90°C with the gas spray gun.
④ The fixed rubber surface is heated and fused and affixed to the upper part of the pipeline, that is, the opposite joint should be above the middle of the pipeline.
⑤ The rubber surface of the shrink belt is slightly heated, the purpose is to remove moisture and soften the glue, the triangle of the shrink belt is glued and compacting at 2/3 of the location, requiring the fixed belt to be added from the bottom of the tube along the middle circumference, and the rubber surface should be heated to strengthen the adhesive bonding. One end of the contraction belt is formed into a triangle in order to increase the contact area between the contraction belt and the pipe.
⑥ When heated to another time of the fixed plate, it is necessary to add a sealing strip to close it to strengthen the end of the contraction band.
After heating, the edge of the fixed belt should have a small amount of glue overflow, and if this effect is not achieved, it should continue to be heated.

Contact: Michelle Jiang
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