I. Research BackgroundPE gas pipes occupy 65% of the urban gas piping market due to the advantages of corrosion resistance, ease of construction, and long service life (China Urban Gas Association, 2024). However, environmental stress cracking (ESC) causes 38% of pipeline leakage accidents, especially in the heat fusion joints and branch pipe tees are more concentrated (Figure 1).Second, the core issue: stress cracking mechanism analysis1. Classification of failure modesType Causes Typical scenariosSlow crack growth (SCG) Long-term hydrostatic stress + small molecule infiltration After 5-8 years of use in buried pipelineRapid Crack Progression (RCP) Impact loading +...

I. BackgroundPVC-U four-hole pipe with **“2 big and 2 small” symmetric structure** (2 Φ40mm main holes + 2 Φ25mm sub-holes, as shown in Fig. 1) has become a cost-effective choice for the scenarios of cellular communication and park power. Compared with single-hole pipe, its synchronized cable threading efficiency is increased by 60%, but it is found in the project:Cable friction resistance is too large when threading (47% of construction complaints)Rainy season water inside the pipe drainage is not good (resulting in cable corrosion accounted for 32%)Second, the core problem: runner structure defects analysisThrough the cable traction...

I. BackgroundUnder the background of 5G communication, intelligent transportation and other infrastructures, PVC-U nine-hole pipe has become an ideal choice for communication cable and electric power threading pipeline due to its advantages of low cost, strong corrosion resistance and convenient construction. It consists of 9 Φ32mm sub-pipes in a honeycomb combination (Figure 1), compared with the traditional single-hole pipe, space utilization increased by 40%, but the reliability of the connection of the interface of the multi-pipe has become a key problem in engineering applications.Second, the core problem: interface failure mode analysisThrough the statistics of 100 engineering...