How can spiral winding trenchless pipe repair for municipal pipelines ensure structural integrity during live water operations?
Publish Time: 2025-09-16
In urban underground pipe networks, drainage and sewage pipes often face corrosion, ruptures, and misaligned joints after long-term operation, necessitating urgent repair. However, traditional excavation and replacement methods are not only costly but also severely impact traffic, the environment, and residents' lives. Against this backdrop, spiral winding trenchless pipe repair technology for municipal pipelines has emerged as a vital tool for maintaining modern urban infrastructure. One of its greatest advantages is its ability to complete repairs without draining the pipes or interrupting water flow—a process known as "live water operations."1. Steel Strip Material and Anti-corrosion Treatment Ensure Basic StrengthThe core material for spiral winding trenchless pipe repair is high-strength galvanized or stainless steel strip. This strip is pre-pressed into a specific cross-sectional shape using an extruder at the factory and then rolled into coils for delivery to the site. This steel strip undergoes a cold-rolled strengthening process, resulting in excellent tensile and compressive properties. Furthermore, the surface is treated with anti-corrosion treatments such as hot-dip galvanizing, galvanized aluminum, or epoxy coatings, effectively resisting corrosion from corrosive media such as hydrogen sulfide and chloride ions in wastewater. This ensures the repaired pipe maintains structural integrity in humid, highly corrosive environments, with a service life of over 50 years.2. Spiral Winding Technology Achieves a Self-Supporting StructureUnder water-borne conditions, the repair process begins at the inspection well. After assembly in the well, the spiral winding trenchless pipe repair process involves continuously feeding steel strips into the old pipe and spirally wrapping them around a rotating platform to form the new pipe. Each coil of steel strip is mechanically connected using a precise interlocking structure (such as double-locking or triple-interlocking) to form a continuous, seamless cylindrical liner. This interlocking method eliminates the need for welding or bolting and rapidly forms a self-supporting structure in the presence of water flow, resisting external soil pressure and internal water pressure, preventing displacement or deformation of unsecured sections due to erosion.3. Real-time Control Ensures Forming Precision and SealingDuring the winding process, the equipment is equipped with sensors that monitor pitch, roundness, tension, and engagement depth in real time, ensuring each coil of steel tape is precisely aligned to avoid gaps or misalignment. Especially in wet environments, where water flow can disrupt the conveyance of the steel tape, advanced control systems automatically adjust the winding speed and tension to maintain consistent forming quality. Furthermore, some systems fill the annular gap between the new and old pipes with cement-based or polyurethane grouting after winding is complete, further strengthening the overall structural rigidity and preventing groundwater infiltration that could cause voids or subsidence.4. Joint Sealing and Waterstop Design to Address Dynamic Water FlowTo prevent water leakage from the ends of the new pipe or joints, the repair system incorporates specialized waterstop seals or expansion plugs at the beginning and end of the new spiral pipe, tightly connecting it to the manhole wall or existing pipeline. Furthermore, the steel tape engagement points are typically inlaid with rubber seals or coated with waterproof adhesive, creating a double waterproof barrier. This effectively prevents water infiltration even under high flow rates or intermittent full pipe flow, ensuring the seal and structural stability of the repaired section.5. Adapts to Complex Working Conditions and Improves Overall Load-Bearing CapacityThe spirally wound liner and the existing pipe form a "casing structure," creating a synergistic load-bearing system. The new pipe bears the primary load while restraining further deformation of the existing pipe, significantly improving the overall pipeline's resistance to compression, bending, and seismic shock. Even if the existing pipe is partially damaged or collapsed, the spiraled pipe can span the defective area, restoring the pipeline's continuity and functionality.The municipal pipeline spiral winding trenchless pipe repair technology utilizes high-strength steel belts, a precise interlocking structure, and real-time control and sealing design to successfully restore pipeline structural integrity even under flooded conditions. This technology not only avoids large-scale excavation, but also significantly shortens construction time and minimizes social impact, making it an ideal solution for the sustainable renewal of urban underground pipeline networks.
