🧿1. Principle of the Socket-and-Spigot Connection

The socket-and-spigot connection is a typical joint type for cement pipes and is a flexible connection. Its structure is as follows:

- Structural Components:

- The socket (expanded end) and the spigot (reduced end) nest together, with the spigot inserted into the socket to form a sleeve connection.

- Rubber seal: Installed in the socket groove, it expands under pressure to fill the gap, forming the first waterproof barrier.

- Filling layer: Traditionally, cement mortar is applied to the outside of the joint, but this is prone to cracking. Advanced technology uses high-strength, micro-expanding cement slurry injected into the joint cavity to reduce shrinkage cracks.

- Mechanical Characteristics:

- The socket-and-spigot design allows for slight axial displacement (≤10 cm) and rotation (≤1.5°) of the pipe to accommodate foundation settlement or thermal expansion and contraction.

- However, large-diameter pipes above DN1000 are prone to cracking due to hoop stress concentration. Therefore, the socket-and-spigot design is more suitable for small and medium-sized pipes.

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🧿II. Common Causes of Leakage

DN1000 Cement Pipe Socket and Spigot Leaks are often caused by a combination of factors:

Foundation Disturbance: Soft soil settlement or vehicle-borne vibration can cause pipe misalignment and rubber ring dislodgement (accounting for over 60% of leaks).

Rubber Ring Failure: Misaligned installation, aging deformation, or popping out due to low-temperature shrinkage.

Pipe Defects: Concrete is not poured densely, resulting in a honeycombed surface, or the mortar at the joint is insufficiently waterproof.

External Stress: Vibration from adjacent construction sites and sudden temperature changes can cause micro-cracks in the joint.

🧿III. Repair Methods for DN1000 Cement Pipe Socket and Spigot Leaks

Emergency repairs for large-diameter pipelines require both timeliness and durability. The mainstream methods are as follows:

Quick Repair Techniques

- Baoshuo Brand Socket Repair Clamp (Emergency Repair Clamp, Emergency Repair Section)

- Procedure: Clean the leak → Fill the gap with quick-drying cement → Install the two-piece steel clamp and tighten the bolts. - Advantages: Complete within 2–4 hours, without shutting off the water supply, suitable for any leak. Baoshuo brand repair clamps can be customized to the length of the leaking pipe, ranging from 0.5m to 4m in length. Clamp diameters range from DN50 to 4000mm, and can repair pipes with pressures exceeding 1.6 MPa.

- Limitations: Cannot repair out-of-round pipes.

2 Micro-expansive cement grouting + steel reinforcement

- Process:

① Drilling (with grouting holes/vents above and below the socket) → ② Installing the grouting head → ③ Pressure-injecting high-strength micro-expansive cement grout → ④ Covering with "two oils and two materials" (asphalt + felt) for enhanced sealing.

- Supporting measures: Use a tensioned steel plate sealing device to secure the joints and prevent displacement during grouting.

Process Upgrade (Preventive Design)

- Double-Sealed Socket-and-Spigot Structure:

Inner brick joint adhesive layer + outer rubber ring + micro-expanding cement filling cavity for triple protection.

- Intelligent Foundation Treatment:

Soft soil foundations utilize crushed stone replacement and concrete base slabs to reduce settlement risk.

> Decision Recommendations:

> - Settlement and leakage/large diameter/sudden leakage → Prioritize the use of socket-and-spigot repair clamps for quick waterstopping;

> - New Projects → Adopt a triple-sealed socket-and-spigot design and strengthen the foundation.