1. Research Background MPP (Modified Polypropylene) power corrugated pipes, featuring a "corrugated structure + high-temperature resistance modification" (Figure 1), have become the preferred choice for trenchless laying of 10kV-35kV power cables. Compared to traditional PVC-C pipes, they increase pulling construction efficiency by 40%. However, in long-distance directional drilling (>500m) and large-curvature bends (R < 15D), pipe failures are prominent: According to 2024 State Grid statistics, 32% of MPP pipe construction accidents are caused by tensile fractures. 28% of municipal engineering reworks are due to bending instability. 2. Core Issue: Mechanism of Mechanical Failure in Pulling Pipes Through full-scale pulling tests (referencing CECS 165:2004) and finite element simulation, three failure modes and...

I. Research backgroundPVC double-wall corrugated pipe has a share of 42%** in the field of municipal drainage and sewage disposal in building communities by virtue of the structure design of **“outer wall corrugated + inner wall smooth” (Figure 1) (2024 China Plastics Processing Industry Association data). However, traditional products face two major contradictions:Insufficient ring stiffness: easy to deform when the depth of soil cover > 3m (58% of the failure cases)Excessive weight: dn300mm pipe weighs 12kg/m, increasing transportation cost.Second, the core problem: structure - performance contradiction analysisThrough the ring stiffness test (GB/T 9647) and finite element...

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 +...