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Steel-Plastic Composite Structure Optimization of Steel-Belt Reinforced PE Corrugated Pipes ——Buried Heavy-Duty Pipeline Applications Based on CJ/T 225 Standard
1. Research Background Steel-belt reinforced PE corrugated pipes occupy 63% of large-diameter (DN600mm+) buried pipelines (2024 CPPIA), offering SN16 ring stiffness (100% higher than HDPE pipes). Key challenges: Interfacial peel strength <30N/cm (CJ/T 225-2011 limit) Ovality >4% at >5m burial depth 1.2% leakage rate with traditional joints 2. Core Issue: Steel-Plastic Composite Failure 2.1 Interfacial Failure Modes Tensile tests (GB/T 2790-1995) and SEM reveal: Mechanical interlock failure (60%): Inadequate steel surface treatment Chemical failure (30%): Poor compatibility between steel coating and PE Environmental failure (10%): Hydrolysis under long-term water immersion 2.2 Key Parameters Parameter GB Requirement Engineering Challenges Galvanized layer thickness (μm) ≥8 Coastal areas require >15μm Interfacial shear... -
Ring Stiffness Optimization and Soil-Pipe Interaction Design of MPP Double-Wall Corrugated Pipes ——Buried Pipeline Engineering Applications Based on GB/T 19472.1 Standard
1. Research Background MPP double-wall corrugated pipes occupy 32% of buried pipeline markets (2024 CPPIA), but face two technical bottlenecks: ＞4m burial depth causes ＞5% ovality (GB/T 19472.1-2019 limit) Backfill compaction leads to 20-year lifespan difference 2. Core Issue: Ring Stiffness Degradation 2.1 Mechanical Behavior Full-scale ring stiffness tests (GB/T 9647-2015) and FEM reveal:  Crests bear 65% axial stress, prone to buckling Valleys suffer strain concentration, causing plastic deformation Traditional uniform wall thickness uses only 62% material efficiency 2.2 Soil-Pipe Interaction Model Modified Spangler equation relates stiffness ratio (\(E'_s/E_p\)) to deformation:\(\delta = \frac{KD^3}{EI + 0.061E'_sD^4} \times 100\%\) Where: \(E'_s\) increases 28% per 10% compaction increase MPP \(E = 1.2GPa\) < HDPE \(1.5GPa\) 3.... -
High-Temperature Performance Optimization and Cable Current Carrying Capacity of MPP Power Protection Pipes ——Power Cable Protection Applications Based on DL/T 802.11 Standard
1. Research Background MPP (Modified Polypropylene) power protection pipes occupy 58% of 10kV-35kV cable protection (2024 China Electricity Council), but face two bottlenecks under high load: >60℃ long-term temperature causes >5% thermal deformation, hindering heat dissipation Low thermal conductivity 0.2W/(m·K) reduces cable current capacity by 22% vs. direct burial 2. Core Issue: High-Temperature Degradation Mechanism 2.1 Thermo-Electric Coupling Failure TMA and cable current tests (GB/T 12527-2008) reveal:  Temperature rise: Cable losses heat pipes to 70-80℃ Material softening: MPP Vicat temp 120℃, but crystallinity loss causes creep Current reduction: Increased thermal resistance creates a vicious cycle 2.2 Key Parameters Parameter GB Requirement Field Measurement Influence Thermal deformation temp (℃) ≥93 95-100 ★★★★☆...
