Underground pipelines play an important role in production and life. With the passage of time, due to corrosion, long operating years and other reasons, the pipeline will inevitably have various damages and leaks, so it needs to be repaired and even replaced. In addition, the whole line is replaced with new pipelines, which is not only a huge amount of work, but also has a long construction period.
The trenchless repair technology for pipelines can restore the safe operation of pipelines more efficiently and quickly by adopting scientific methods without affecting traffic. Moreover, the construction process will not pose a threat to the environment, and the construction period is short, which can reduce the impact on people’s daily life and production, and has better economic and social benefits.
1. Applicability of trenchless repair of pipelines
The trenchless repair technology for pipelines is not suitable for the repair of all damaged pipelines. At present, the line shape of the pipeline cannot be reshaped. For example, the pipelines such as too large staggered openings and large deformation of the pipe shape need to be excavated and renovated.
2. After the repair, ensure the drainage capacity and meet the requirements of pipeline dredging and maintenance
The drainage capacity of the repaired section should generally meet the design drainage, so the drainage capacity after repair should be calculated. When it cannot be satisfied, measures to make up for the missing flow should be proposed, otherwise, the excavation method should be used for overturning and updating. If the selected repair technology makes it impossible for the maintenance unit to perform maintenance, another repair technology should be selected. If special equipment is required, the configuration should be recommended.
3. The site conditions meet the requirements for trenchless repair of pipelines
When the underground pipelines, traffic conditions, surrounding environment and other factors do not meet the conditions for excavation and construction, but meet the conditions for trenchless repair of the pipeline, the trenchless repair method can be given priority on the premise of meeting the flow requirements of the repaired pipeline. .
1. Before repairing the trenchless pipeline, the inner wall of the pipeline should be inspected, and it is required to accurately locate and judge the defects of the pipeline.
2. If it is found that there is local leakage in the pipeline, which affects the curing and repair of the UV lining, local point repair should be carried out first.
3. If it is found that the inner wall of the pipeline has defects such as large protrusions and foreign objects interspersed, it should first use a pipeline cutting and grinding robot for local treatment to avoid scratching the lined hose.
4. Before the repair of the trenchless pipeline, the water pipeline shall be blocked, and then the high-pressure cleaning vehicle and the sludge suction truck shall be used to dredge, flush and pump the repaired pipeline.
Through the trenchless repair technology of the pipeline, the laying direction and burial depth of the underground pipeline can be controlled with high precision, and the pipeline can bypass the underground obstacles. To a large extent, the trouble of demolition and damage to the environment are avoided. Therefore, the prospect of trenchless repairing technology in the field of underground pipeline repairing is bound to be broader.
The company has a variety of trenchless repair technologies and processes. During repair, we can choose a suitable pipeline lining technology according to the outer pipe diameter, service life, pressure bearing capacity and burying environment to repair damaged pipelines and solve potential safety hazards.
1. JMPE interspersed repair method
The company’s JMPE interpenetration repair method is to intersperse PE pipes with a smaller diameter than the original pipe in the pipeline to be repaired under the condition that the diameter of the pipe is reduced and the normal pipeline transportation is not affected. This kind of repair technology is suitable for water supply, drainage and gas pipelines of various materials (carbon steel, cast iron, cement, PE, etc.) of DN200-DN2000 diameter. The lined pipe can independently bear the design pressure of the pipeline, has low requirements on the original pipeline, and can safely prolong the service life of the pipeline for 50 years. The single construction length of the hard PE pipeline interspersed can reach 1500 meters, which can effectively solve the problem of pipeline repair without excavation conditions such as pipelines near sea, rivers, roads, and railways. The pipeline repaired by interpenetration can not only increase the strength of the pipeline, but also prevent the leakage and corrosion of the pipeline, and the quality of the repaired pipeline is relatively stable for a long time, which is a quite effective method in the trenchless repair technology.
2. CIPP flip in situ curing method
The CIPP in-situ curing method is to line a layer of thermosetting material on the existing pipeline wall, and use the lining to turn over to pull the soft liner to a predetermined position, and then heat it to cure it, so as to form a liner that closely fits with the pipeline.
CIPP is mostly suitable for the repair of pipelines with a diameter below DN600, the pipelines are basically intact, and can withstand the design pressure. The length of one CIPP lining can reach 1000 meters, the construction speed is fast, and the comprehensive cost is low.