The urban underground pipe network is the "blood vessel" that maintains the operation of the city, but as the service life increases, many old pipes have cracks, corrosion, deformation and other problems, which seriously affect the functions of drainage and water supply. The traditional excavation repair method will not only damage the road surface and affect traffic, but also produce high construction costs and long construction periods, which bring many inconveniences to urban life. In this context, trenchless pipe repair technology has gradually become the mainstream of the industry, and HDPE carat pipe (high-density polyethylene wound structural wall pipe) has become the "right-hand man" in pipeline repair projects due to its excellent performance. As a well-known brand in the field of plastic pipes, the HDPE carat pipe produced by AD Pipe is made of high-density polyethylene raw materials and is made by hot winding molding process, which has extremely high toughness and impact resistance. Even in complex underground environments, it can effectively resist soil pressure and external loads, and avoid secondary damage caused by pipeline deformation. At the same time, HDPE materials themselves have excellent corrosion resistance, good resistance to acid, alkali, salt and other media, and can operate stably in harsh media such as sewage and industrial wastewater for a long time, fundamentally solving the corrosion problem of old pipelines. In pipeline repair projects, HDPE carat pipes are mainly constructed by "lining method" or "interspersing method". The lining method is to fit the HDPE carat pipe to the inner wall of the old pipe by heat shrinkage or mechanical expansion to form a solid "protective layer", which not only repairs the damage of the original pipe, but also improves the overall pressure-bearing capacity of the pipe; the interspersing method is to insert the HDPE carat pipe directly into the inside of the old pipe, and use its flexible characteristics to adapt to the direction of the old pipe. It is suitable for pipe repair with large pipe diameter and less serious deformation. No matter what method, there is no need to excavate a large area of pavement, and the surrounding traffic and residents' lives will not be affected during the construction process. The construction period is shortened by more than 50% compared with the traditional method, and the construction cost is also greatly reduced. Taking municipal sewage pipe repair as an example, the old sewage pipe in a city has been in disrepair for a long time, and there are many leaks and corrosion. After using the HDPE carat pipe for lining repair, not only the leakage problem is completely solved, but also the drainage capacity of the pipeline is improved. During the construction period, 1.2 kilometers of pipeline repair was completed in only 3 days, which greatly reduced the impact on the surrounding business district. In addition to municipal sewage pipes, HDPE carat pipes are also widely used in industrial drainage pipes, residential water supply and drainage pipes and other repair scenarios. Its flexible connection method (such as electric hot melt connection) ensures the tightness of the pipeline interface, avoiding the problem of groundwater pollution or pipeline blockage caused by interface leakage. In addition, HDPE material itself is non-toxic and harmless, meets environmental protection requirements, and will not cause pollution to the transportation medium. It is especially suitable for the repair of drinking water pipes. AD Pipeline has always been committed to providing efficient and reliable solutions for pipeline projects. The application of its HDPE carat pipes in repair projects not only reflects the advantages of trenchless technology, but also shows the potential of plastic pipes in urban pipe network renewal. With the continuous advancement of urban construction, HDPE carat pipes will play an important role in more pipeline repair projects and escort the healthy operation of urban "blood vessels".