Table of Contents
- General Requirements
- Support Line Measurement
- Sheet Pile Delivery and Storage
- Construction Sequence
- Inspection, Lifting, and Stacking
- Guide Frame Installation
- Sheet Pile Driving
- Sheet Pile Extraction
1. General Requirements
- Positioning: Steel sheet piles must align with design specifications, ensuring adequate space for formwork and demolition at the trench edge.
- Layout: The support structure should maintain straight, orderly lines to optimize standard sheet pile usage and simplify bracing. Irregular shapes must be avoided.
- Safety Protocols: Throughout construction (excavation, lifting, reinforcement, concreting), avoid impact or unauthorized removal of supports. No welding, cutting, or heavy loads are permitted on bracing.
2. Support Line Measurement
Mark sheet pile driving positions with lime powder based on the trench design width.
3. Sheet Pile Delivery and Storage
- Schedule deliveries per construction progress to avoid delays.
- Distribute piles along the support line to minimize secondary transportation.
4. Construction Sequence
- Site Marking → 2. Trench Excavation → 3. Guide Frame Installation → 4. Pile Driving → 5. Frame Removal → 6. Waling & Bracing → 7. Earthworks → 8. Foundation (Force Transfer Zone) → 9. Bracing Removal → 10. Underground Structure → 11. Backfilling → 12. Pile Extraction → 13. Void Treatment
5. Inspection, Lifting, and Stacking
Inspection
- Visual Checks: Assess surface defects, dimensions (length/width/thickness), straightness, and lock integrity.
- Remove obstructive welds.
- Reinforce perforated/damaged sections.
- Measure corrosion-affected thickness.
- Material Tests: Conduct chemical/mechanical analyses, including tensile, bend, lock strength, and elongation tests. Test frequency: 1–2 samples per 20–50 tons.
Lifting
- Use two-point lifting to protect lock seams. Limit bundles to 5 piles max.
Storage
- Choose a flat, load-bearing ground.
- Stacking Rules:
- Organize by type/size/length with clear labels.
- Layer piles (≤5/layer) with 3–4m spaced timber dunnage.
- Align dunnage vertically; max stack height: 2m.
6. Guide Frame Installation
Purpose: Ensure verticality, precision, and prevent deformation.
Specs:
- Single-layer, double-sided frames with 2.5–3.5m spaced walking piles.
- Inner spacing = Pile wall thickness + 8–15mm.
Key Steps:
- Adjust frame position via theodolite/level.
- Optimize height for efficiency.
- Prevent frame sinking/deformation during driving.
- Maintain perpendicularity; avoid pile collisions.
7. Sheet Pile Driving
Critical for waterproofing/safety. Follow these steps:
- Use crawler excavators; verify underground utilities beforehand.
- Inspect each pile—reject/repair corroded/deformed locks.
- Apply grease to locks for smoother driving/extraction.
- Monitor inclination; redrive if deviation exceeds tolerance.
- Ensure 2 m+ embedment depth and tight interlocks. For corners, use special angled piles or seal gaps with tires/cloth.
- Observe pile stability during excavation; add symmetric bracing if tilting/bulging occurs.
8. Sheet Pile Extraction
Post-backfilling, extract piles carefully to prevent ground settlement/structure damage.
Methods
- Vibratory Hammer: Disrupts soil adhesion via vibration + auxiliary lifting.
Key Notes
- Start Point: Begin ≥5 piles away from corners; reverse driving sequence.
- Technique: Loosen locks via vibration before lifting. For stubborn piles, combine vibratory/drop hammers.
- Load Control: Keep crane load below the vibrator’s spring limit.
- Power Supply: 1.2–2.0x hammer’s rated power.
Troubleshooting
- Stuck Piles:
- Re-drive with vibratory hammer.
- Drive adjacent piles to reduce friction.
- Inject bentonite slurry into side slots.
- Common Issues:
- Tilting: Correct via wire-rope alignment or pre-set deviation.
- Twisting: Use clamps or pulley braces on locks.
- Jamming: Weld temporary angle iron supports.
