Application Of Underground Sewage Pipes In Polymer Composite Grouting Technology In Trenchless Repair

With the development of economy and urbanization of China, the length of buried pipeline is growing rapidly, bringing convenience to people's lives. However, the condition of aging pipes is worsening, which poses a serious threat to security of surrounding buildings, soil and groundwater environment. Traditional pipeline repair technology, which increases workload, coats and duration, and seriously affected the normal life of nearby residents, is gradually being replaced by trenchless rehabilitation technology.Polymer composite material composes with polyurethane, having the advantages of light weight, waterproof, high safety and high reliability, has been widely used in various engineering fields such as dams, tunnels and underground construction. Based on the analysis of environmental and physical properties of polymer composites, it was found that the material is non-toxic, harmless, and anti-corrosive under normal conditions of weak acid, weak base and common organic solvents, also has good impermeability, compression, tensile strength and expansion properties. With the increase of the density of the material, its physical properties are further improved. According to the field situation, the suitable density of the material can be determined, and the best combination of performance and economy can be achieved.With consideration of the problems parts of underground sewers have to face and the site repair goal in Guangzhou City, new polymer composite materials and sophisticated trenchless repair technique have been applied in the repair of some representative sections of pipe. Based on the practical project need, serious leakage nodes of Guangzhou City Kangle Bay sewage pipeline, and the poor geological nodes of Haizhu main sewage pipe which were buried in soft soil, sand layer, and underground river etc, were selected in this research. The research of repairing the above-mentioned nodes by making different repair plans and adopting different techniques according to the practical situation, achieved good results, and fully met the expected goal, even went far beyond expectations in environmental protection and economic benefits.The case of repairing damaged sections of pipes successfully under complicated geological conditions of lots of underground pipelines, soft soil-layers, underground river and so on, by using non-expandable hydrophilic-polymer-reaction type two-component composite materials, combined with sophisticated trenchless grouting repair technology, will provide the theoretical basis and technical support for the trenchless construction and management of the urban central drainage pipeline.