With the development of urban construction and the increasing prominence of aging pipeline issues, the rehabilitation of drainage pipelines has become crucial. Traditional excavation rehabilitation methods are not only time-consuming and labor-intensive but also cause significant impacts on urban traffic and the environment. Therefore, trenchless rehabilitation technology has gradually become the mainstream method for drainage pipeline rehabilitation. We will introduce several common trenchless rehabilitation methods and their key quality control points.
The UV curing method involves pulling a light-cured resin-impregnated soft liner into the existing pipeline, and curing it with UV light to form a new pipe liner. This is a trenchless rehabilitation method.
Advantages
The liner pipe closely adheres to the original pipeline, eliminating the need for grouting.
Fast construction speed and short project duration.
Suitable for rehabilitationing non-circular pipelines.
The liner pipe can be continuously installed, allowing for single or multiple pipeline segments to be completed at once.
Smooth surface reduces flow loss.
Disadvantages
High requirements for pipeline pre-treatment.
Special construction equipment is required, and high levels of skill and experience are demanded from workers.
Intercepting and diverting the flow during construction and strictly controlling water accumulation in the pipeline are necessary.
Quality Control Points
The bending elastic modulus, tensile strength, wall thickness, and permeability of the cured pipeline should meet the design requirements and current national standards.
There should be no wet spots, leaks, or seepage in the rehabilitationed pipeline.
The surface of the liner pipe should be smooth, and free from holes, cracks, or weak spots.
The cut at the starting point of the liner pipe should be neat, sealed, and dense.
The thermal (steam) curing method is similar to the UV curing method and involves pulling or inversion of a soft liner impregnated with thermosetting resin into the existing pipeline, and curing it with hot water or steam to form a new pipe liner.
Advantages
The thermosetting resin has high adhesion and durability.
Disadvantages
The curing speed is relatively slow, leading to significant water resource wastage.
Controlling the stability of steam supply is challenging, making the liner pipe susceptible to uneven heating.
There are certain risks associated with using mobile steam equipment.
Quality Control Points
The quality control points are the same as those for the UV curing method.
The spraying method involves using centrifugal or pressure spraying techniques to apply rehabilitation materials such as cement-based or polymer materials to the inner surface of the existing pipeline, forming a liner or coating. This is a trenchless rehabilitation method.
Advantages
Broad application range, not limited by pipeline shape, diameter, or segment length.
Pipeline displacement, angle changes, and variations in diameter and section have minimal impact on the spraying method.
Simple operation and convenient construction.
Disadvantages
High requirements for pipeline pre-treatment, with the preliminary preparation consuming considerable time.
Quality Control Points
The performance of the spraying material and the thickness of the liner should meet the design requirements.
The compressive strength of mortar, and the pull-out strength of cement-based and polymer materials should meet design requirements.
The coating surface should be smooth, free of holes, cracks, or scratches.
In summary, trenchless rehabilitation technology plays an important role in the rehabilitation of drainage pipelines. Different rehabilitation methods have their own advantages and disadvantages. Choosing the appropriate rehabilitation technology and strictly controlling quality are key to ensuring rehabilitation effectiveness. Trenchless rehabilitation technology not only improves construction efficiency and reduces costs but also effectively minimizes negative environmental and societal impacts. It is a crucial technology in modern urban pipeline rehabilitation.
