1、 Construction preparation stage

1. Material inspection and storage
   • Visual inspectionAfter the pipes arrive at the site, their appearance should be checked for completeness, without cracks, dents or deformations, and the specifications and qualification certificates should be verified.
   • storage requirementsThe site should be flat, and the height of pipe stacking should not be too high (generally not exceeding 1.5 meters) to prevent deformation under pressure; Avoid direct sunlight or rain, stay away from heat sources and corrosive substances.
2. Trench excavation and foundation treatment
   • Groove sizeThe width of the groove bottom needs to meet the installation operation requirements, usually more than 600mm wider than the pipe diameter; The bottom of the groove should be flat, continuous, and free of hard objects (such as stones or bricks). If encountered, over excavation and backfilling with sand and gravel compaction are required.
   • Basic processing：
     • General soil qualityLay a gravel foundation with a thickness of not less than 150mm and compact it.
     • soft soil foundationSoil replacement or reinforcement treatment (such as pile driving, cushion reinforcement) is required to prevent pipeline settlement.
   • Drainage measuresDuring rainy season construction, the length of the trench should be shortened to achieve fast completion and backfilling; If bubbles occur, the softened surface soil should be removed and replaced with sand and gravel or medium coarse sand.

2、 Pipeline installation operation

1. Pipe laying and installation
   • Lower pipe methodUse flexible straps (such as nylon straps) to smoothly lower the pipe, and it is strictly prohibited to use steel wire ropes to lift through the pipe to prevent damage to the pipe body; When the pipe diameter is large or the groove is deep, non-metallic ropes can be used to slide the pipe.
   • Pipeline alignmentThe pipeline should be placed strictly according to the design requirements in terms of position and slope, with a joint gap of no more than 10mm and a relative offset of no more than 7mm from the centerline to ensure the connection effect.
   • Stable management measuresTo prevent the axis of the pipeline from moving when the interface is closed, fill the woven bag with yellow sand, seal it, and press it onto the top of the pipeline.
2. Pipe cutting and adjustment
   • cutting requirementsIf it is necessary to adjust the length of the pipe, an electric saw or a woodworking cutting saw should be used, and the end face must be vertical and flat without damage; After cutting, burrs and debris need to be cleaned.
   • length matchingCut the pipes according to the distance between the two wells to avoid waste or difficulty in connection.

3、 Pipeline connection method

1. Electric heating melting belt connection (suitable for large-diameter pipelines)
   • operating steps：
     • Clean the surface of the pipe and electric melting belt to ensure no dirt or oil stains.
     • Wrap the electric heating strip around the connection part of the pipe and fix it with a special fixture.
     • Apply electric heating according to the parameters specified by the manufacturer (such as voltage and heating time) to fuse the melt strip with the pipe material.
     • Before cooling to room temperature (about 8-12 hours), it is strictly prohibited to move or bend the pipeline, otherwise it will affect the sealing.
   • Precautions：
     • The power supply must comply with safety regulations (such as using a generator of 45KW or more), and the cable length should not exceed 100 meters.
     • An operation pit (1000mm wide and 300mm deep) needs to be excavated at the interface area for easy operation and inspection.
2. Heat shrink tape connection (suitable for small and medium-sized pipelines)
   • operating steps：
     • Clean the connection end of the pipe and preheat it (such as uniformly heating it to 80-90 ℃ with a gas spray gun).
     • Wrap the heat shrink tape around the pipe, heat it from the middle to both sides, and use your hands to smooth it out and avoid bubbles.
     • Heat and shrink the adhesive surface of the tape, remove moisture and soften the adhesive layer, bond the triangle at the positioning, and compact the fixing tape.
   • Precautions：
     • The shrinkage band model should match the pipe diameter, and the heating should be uniform to avoid local overheating and burning.
     • Pipelines with a diameter of ≥ 500mm require two layers of inner and outer layers, while pipelines with a diameter of ≤ 400mm only require one layer of outer layer.
3. Sealing ring socket connection (quick and effortless)
   • operating steps：
     • Insert the sealing rubber ring onto the pipe socket end, ensuring that the tooth crest on the rubber ring is facing towards the socket direction without distortion or accumulation.
     • Clean the inner wall of the socket, apply lubricant (such as silicone oil), and use a tensioner or hand hoist to smoothly insert the socket into the safety line position.
   • Precautions：
     • The rubber ring should be intact and the lubricant should be evenly applied to avoid interface leakage.
     • When using socket connection, the socket should be in the direction of water flow, and the socket should be in the opposite direction of water flow.

4、 Requirements for backfilling treatment

1. Backfilling timing and materials
   • Backfilling timingAfter the pipeline installation acceptance is qualified, it should be backfilled immediately to avoid long-term exposure that may cause the pipeline to float or be damaged.
   • backfill material：
     • Within a range of 0.5m from the bottom foundation to the top of the pipeManual backfilling must be used, and mechanical bulldozing is strictly prohibited; Backfill soil shall not contain hard materials such as gravel, bricks, frozen soil blocks, etc.
     • 0.5m above the top of the pipe to the groundMechanical backfilling can be used, but it needs to be compacted layer by layer, with each layer thickness not exceeding 300mm.
   • Density requirementThe compactness of backfill soil must comply with the design or manufacturer's technical specifications to prevent damage to the pipeline due to uneven settlement.
2. Special scenario handling
   • Pipeline and inspection well connection：
     • plastic inspection chamberRubber ring socket connection is used.
     • Brick built cement wellThe pipeline can be directly built into the well wall, but it needs to be treated with waterproofing measures (such as applying waterproof mortar).
   • Pipeline repairIf the pipe wall is locally damaged (aperture ≤ 60mm or crack ≤ 1/12 of the pipe circumference), it can be repaired with a welding gun; When the damage exceeds the scope, it is necessary to cut off the damaged pipe section and replace the pipe or build an inspection well.

5、 Safety protection measures

1. Construction safety
   • personnel protectionConstruction personnel are required to wear protective equipment such as insulated gloves, safety helmets, and non slip shoes to avoid burns, scalds, or mechanical injuries.
   • fire prevention measuresKeep away from flammable materials during hot melt connection and equip with a fire extinguisher; Construction must be stopped and lightning protection measures taken during thunderstorm weather.
   • mechanical operationWhen using cranes or excavators, they must be operated by professionals, follow safety regulations, and prevent equipment from overturning or colliding with pipelines.
2. environmental safety
   • waste disposalWaste generated during construction, such as cutting debris and packaging materials, should be centrally cleaned to avoid contaminating soil or water sources.
   • Noise controlNighttime construction requires noise control to avoid affecting surrounding residents.