Failure modes of plastic pipes in sewage

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Common failure modes of plastic pipes in sewage applications can be divided into three categories: structural failure, functional failure, and material performance degradation, as follows:: 1. Structural failure refers to the destruction of the structural integrity of the pipe and the loss of basic pressure-bearing and drainage capabilities.: Deformation and collapse: Plastic pipes have limited strength and durability. When they are buried under pressure for a long time and the foundation settles unevenly, they are prone to overall deformation. In severe cases, they can directly collapse and block the pipes. Plastic pipes such as double-wall corrugated pipes have the most significant problem of deformation defects. rupture cracking: When soil settlement and external vehicle loads exceed the bending strength of the pipe, the pipe will crack or even break. ； Alternating hot and cold environments will also aggravate stress cracking, and some organic solvents in sewage will accelerate the embrittlement of plastics, further increasing the risk of rupture. Interface leakage: Aging and misalignment of rubber rings, improper installation of sockets, and failure to make a flexible transition for settlement of inspection wells will lead to joint sealing failure and sewage leakage, which will not only contaminate soil and groundwater, but may also cause pavement settlement. 2. Functional failure means that the structure is not completely destroyed, but the drainage function is reduced and affects the operation of the system.: scale blockage: Impurities and grease in sewage will continue to deposit and scale on the walls of plastic pipes, resulting in a reduction in pipe diameter and water passing capacity. ； Large plastic and fiber impurities can also be directly entangled and accumulated, completely blocking pipes and equipment. corrosion swelling: Chemical substances in sewage will cause chemical corrosion to some plastics, causing pipe swelling and performance degradation. ； Grease-containing sewage will accelerate the aging of plastic pipes such as PPR. High-concentration organic sewage may also degrade plastic additives and weaken the strength of pipes. 3. Material performance degradation refers to the gradual deterioration of the physical and chemical properties of the plastic itself during long-term use, gradually causing failure.: Aging and fading: If plastic pipes are used exposed, sunlight's ultraviolet rays will accelerate the photochemical reaction, causing the color to fade, the material to become brittle, and the strength and flexibility to decrease rapidly. stress relaxation cracking: Long-term bearing of soil and ground loads will cause the internal stress of the plastic to gradually release, reduce the toughness of the pipe, and eventually cause brittle cracking. This failure is a progressive deterioration and is difficult to detect in the early stage.