Water supply steel wire mesh skeleton plastic (polyethylene)
Construction Description of Composite Pipe
1、 Trench excavation shall meet the following requirements:
1. When the pipe diameter dn ≤ 500mm, the clear width of each side of the pipe should not be less than 0.3m; When the pipe diameter dn>500mm, the clear width of each side of the pipe should not be less than 0.5m. When it is under the roadway or farmland, the height of pipe top soil should not be less than 1m; It should not be less than 0.7m below the green belt.
2. The trench slope can be determined according to the construction site environment, trench depth, groundwater level, soil conditions, construction equipment and seasonal impact.
3. The elevation of the base shall be strictly controlled during trench excavation, and the undisturbed soil layer of the base shall not be disturbed. The undisturbed soil layer 0.15-0.20m above the design elevation of the base shall be manually cleared to the design elevation before pipe laying. In case of exceeding or disturbance, sand and gravel with particle size less than 40mm shall be used for backfilling, and shall be leveled and compacted to 95% compactness. It is forbidden to backfill with miscellaneous soil. If there are sharp and hard objects at the bottom of the tank, they must be removed and then backfilled with sand and gravel.
4. The tank bottom shall not be soaked in water. If artificial precipitation measures are adopted, excavation can be carried out only after the groundwater level is stabilized below the trench bottom.
2、 The construction of pipeline foundation shall meet the following conditions:
1. The steel mesh skeleton plastic (polyethylene) composite pipe shall be based on flexible pipe. For general soil, a 100mm thick medium coarse sand foundation layer shall be laid on the undisturbed soil foundation below the pipe bottom or the backfilled and compacted foundation. The foundation layer shall reach the compactness of 85%~90% and must be flat.
2. When the trench base is soft soil foundation, Ultra wear-resistant composite pipe When the bearing capacity of the foundation is less than the bearing strength required by the design or the bearing capacity of the foundation is reduced due to the disturbance of the undisturbed soil due to construction precipitation and other reasons, the foundation must be reinforced first. After reaching the specified bearing capacity of the foundation, the foundation layer of medium coarse sand shall be laid.
3. The composite foundation treatment methods such as sand pile and block stone cast-in-place pile should be adopted for the foundation treatment of steel mesh skeleton plastic (polyethylene) composite pipe. Rigid foundation treatment measures such as driven piles, concrete cushion blocks and concrete strip foundations shall not be adopted
3、 The laying, installation and welding of pipes shall meet the following requirements:
1. Before running the pipe, carefully check the model of pipes and fittings and whether they are damaged. If they do not meet the standards, they are strictly prohibited to lay down.
2. During pipe laying, no water shall be stored in the trench, and it is strictly prohibited to soak in the trench or freeze the trench soil.
3. When the pipe laying must cut the pipe length, the mechanical method shall be used for cutting. The cutting section must be flat and perpendicular to the pipeline axis. Open flame burning is strictly prohibited.
4. When the pipe changes the pipe diameter or extends out of the branch pipe, matching pipe fittings must be used. It is strictly prohibited to open holes on pipes and pipe fittings.
5. When the electric melting pipe fittings are connected, the oxide layer on the outer surface of the welding area required by the pipe must be scraped off. The welding surface of the super wear-resistant composite pipe and pipe fittings must not be contaminated with oil, soil, water and other substances that affect the welding quality. The insertion depth of the pipe shall be marked on the surface of the pipe and must be inserted in place.
6. The equipment provided by the pipe manufacturer shall be used for welding, and the operation shall be conducted under the guidance of the manufacturer's technicians.
7. Before power on, the axis at the straight head shall be calibrated to make it on the same axis with the pipeline.
8. In the process of fusion and cooling, it is not allowed to dismantle machines and tools, move and rotate the parts of joints and pipes on both sides, and exert any pressure on the connection parts and pipes.
4、 The trench backfilling construction shall meet the following requirements:
1. The trench shall be backfilled immediately after the pipeline is connected. Before the pipeline tightness inspection, the joints can be exposed, and the backfill height on both sides of the pipeline and above the pipe top should not be less than 0.5m; After the airtightness inspection is qualified, the rest shall be backfilled in time.
2. The trench backfilling shall be carried out symmetrically from both sides of the pipeline at the same time to ensure that the pipeline will not be displaced. If necessary, temporary limiting measures should be taken for the super wear-resistant composite pipe to prevent displacement or floating of the pipe.
3. The range of 0.5m above the pipe top from the pipe bottom foundation must be backfilled manually, and it is strictly prohibited to use mechanical bulldozing for backfilling. When the trench above 0.5m above the pipe top is backfilled mechanically, it shall be evenly compacted from both sides of the pipe axis. When backfilling, the trench shall be free of ponding and sundries, and shall not contain water, silt, organic matter, frozen soil, stones, bricks and other miscellaneous hard objects.
4. Backfilling at low temperature.
5、 Due to its thin wall and stacking factors during storage or transportation, the steel wire mesh skeleton composite pipe may have a weighted ellipse, which can be used normally after being confirmed by the manufacturer's technical guidance personnel, and can be used after on-site rounding if necessary.
6、 During the connection of the electrofusion pipe fittings of the steel mesh skeleton composite pipe, the welding parameters marked on the pipe fittings are reference values, and the parameters need to be adjusted appropriately depending on the ambient temperature, site pipe fitting temperature and the actual wall thickness of the welded pipe until the welding effect is good.
7、 In the process of socket and spigot connection between the steel mesh skeleton composite pipe and the electric melting pipe fittings, under the guidance of the manufacturer's technical personnel, the appropriate flaring or necking operation can be carried out when the deviation of the actual fitting size of the pipe and the pipe fittings exceeds the standard.
8、 During the welding process of pipes and pipe fittings, there is a phenomenon that the welding temperature of different batches of raw materials is different, and the opportunity rate of this characteristic of super wear-resistant composite pipes will increase when pipes and pipe fittings belong to different manufacturers. During the initial test welding, attention shall be paid to the welding effect at the welding position to avoid adverse consequences of this phenomenon.
