I. Key Considerations for Socket-and-Spigot Connections

Pipe and Joint Pretreatment

- Pipe End Inspection: Before installation, clean the inner surfaces of the socket and spigot. Inspect the sealing surfaces for a smooth, flat surface free of scratches, pores, or cracks. If defects are found (e.g., skew greater than 2mm), replace the component. Do not use disassembled sockets for repair.

- Clearance Control: The axial clearance between the spigot and socket for DN3000 pipe must be strictly controlled within a range of 5-15mm to ensure uniform pressure on the sealing ring.

Seal Installation Requirements

- Double "O" rings are recommended. Apply food-grade lubricant before installation to prevent twisting or misalignment. When inserting the spigot into the socket, maintain axis alignment. The rotation angle must not exceed the manufacturer's allowable value.

Short-end and Spacing Specifications

- The distance between the spigot and socket and the edge of the support should be greater than 150mm to avoid stress concentration during installation. - Concrete buttresses are required in soft geological areas (such as silt layers) to prevent joint separation caused by uneven settlement.

FRP Reinforcement Process

- Glue (unsaturated resin) should be applied in layers at the socket joint, alternately wrapped with glass cloth and compacted until the reinforcement layer thickness reaches or exceeds the design value (usually ≥1.5 times the pipe wall thickness) to prevent leaks or glue flow.

🧿 2. DN3000 Special Connector Selection

Given the characteristics of large-diameter pipes, the following two types of connectors are preferred:

Flexible Pipe Connectors

- Applicable scenarios: Emergency repairs, temporary pipelines, or geologically unstable areas.

- Advantages:

- Compatible with pipe ends with an outer diameter difference of up to 24mm, with an allowable axial deviation of ≤3°;

- Stainless steel clamp + rubber sealing sleeve combination, pressure resistance ≥1.6MPa, corrosion resistance;

2. Socket Repair Connector

   - Applicable Scenario: Emergency treatment of socket leaks or seal failures. Baoshuo brand socket repair clamp.

   - Key Operation Instructions:

   - After cleaning the leak, attach the socket repair clamp to the junction of the socket and pipe body and tighten with bolts to create a squeeze seal.

   - Operating pressure ≤ 2.5MPa, applicable temperature -30°C to 80°C.

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III. Key Construction Control Measures

- Lifting Protection: Rubber sheaths should be installed where the wire rope contacts the pipe wall to prevent localized stress damage.

- Water-tightness Test: Conducted before backfilling. For DN3000 pipe sections, allowable water seepage is ≤35.35 m³/(24 h·km). Maintain a constant pressure for 30 minutes.

- Backfill Specifications: No hard objects >10 cm are allowed within 50 cm of the top of the pipe. Layered compaction (voided thickness ≤20 cm) is recommended, with a compaction level ≥95%.

🧿 IV. Summary and Recommendations

DN3000 fiberglass socket connections require strict control of interface precision and reinforcement layer quality. For complex working conditions, flexible connectors can significantly improve fault tolerance and repair efficiency. Before construction, be sure to verify the interface angle and pressure parameters provided by the manufacturer. A dual-insurance design of "buttress + flexible connector" is recommended for geologically weak areas.