1. Suitable Soil Types for Steel Sheet Piling
Steel sheet piling is a versatile and efficient construction method suitable for various soil types, including:
- Sandy soil
- Silt (soft soil)
- Clay (cohesive soil)
- Loam (silty soil)
However, steel sheet piles are not recommended for extremely hard or rocky soils, such as:
- Boulders
- Bedrock
- Gravelly soil
- Crushed stone layers
Construction Methods for Different Soil Types
- Soft/Poor Soil: Direct driving is feasible.
- Isolated Boulders: Use an arc-shaped driving path to avoid obstructions.
- Hard Soil: Implement water jetting or pre-drilling (pre-boring) to ease installation.
- High-Bearing Capacity Soil (>160 kPa): Driving becomes challenging and may require specialized techniques.
2. Steel Sheet Piling in Clay vs. Sandy Soil
- Driving Difficulty: Under the same bearing capacity, sandy soil is easier to drive into compared to clay.
- Extraction Impact:
- During extraction, sheet piles pull out adhered soil, leading to greater ground settlement in clay.
- Sandy soil experiences less soil adhesion, reducing settlement risks.
Mitigation Measures
- Apply lubricants (e.g., grease) to sheet piles to minimize soil adhesion.
- Use vibration-reducing techniques during extraction.
3. Road Cracking Due to Sheet Pile Driving & Extraction
Causes of Cracking
- During Driving: Vibrations compact loose, backfilled, or sandy soils, causing uneven settlement and cracks.
- During Extraction: Stronger vibrations and soil removal lead to greater ground subsidence.
Solutions to Minimize Damage
- Simultaneous Grouting: Inject grout during extraction to fill voids and stabilize the ground.
- Static Pressing (Silent Piling): Reduces vibration, preventing uneven settlement.
Conclusion
Steel sheet piling is highly effective in soft to moderately hard soils, but challenging in rocky or dense gravel layers. Proper techniques—such as pre-drilling, water jetting, and vibration control—can enhance performance. For clay soils, lubrication helps reduce extraction-related settlement, while grouting and static pressing minimize road damage.
By selecting the right method based on soil conditions, construction efficiency and safety can be significantly improved.
