Excessive Support Deformation
Causes: Insufficient steel pipe wall thickness, substandard material (e.g., using Q215 instead of Q235), or failure to provide timely support after over-excavation of the foundation pit, leading to concentrated soil pressure.
Consequences: Causes excessive displacement of the retaining structure, potentially leading to foundation pit collapse.
Connection Node Failure
Manifestations: Loose bolts, incomplete welding, loose joints.
Risks: Uneven stress distribution at nodes, localized instability, and susceptibility to shear failure.
Specification Requirements: High-strength bolts must be tightened with a torque wrench to ensure adequate preload.
Inadequate Prestressing or Rapid Prestress Loss
Common Operational Errors: Loading to design value all at once, failure to apply pressure in stages; failure to lock steel wedges in time.
Environmental Impacts: Temperature changes and soil creep cause natural attenuation of axial force; if not periodically replenished, the support effect will significantly decrease.
Installation Positioning Deviation
Problems: Axis offset > ±30mm, large elevation error, uneven support.
Root Causes: Inaccurate measurement and layout, misaligned bracket welding, deformation due to impact during hoisting.
Impact: Causes eccentric stress, inducing local buckling.
Inadequate Corrosion and Rust Prevention Treatment
Current Situation: In some projects, rust-preventive paint was not applied to steel pipes in humid environments, or the paint was missed at weld seams.
Consequences: After long-term use, the steel cross-section weakens, and the load-bearing capacity decreases.
