Pile Foundation Types: Construction Methods, Cost Analysis & Recommendations

Introduction

Pile foundations are essential for transferring structural loads to stable soil layers. This article compares three common foundation types—driven pipe piles, cast-in-situ piles, and CFG pile composite foundations—covering their definitions, construction processes, cost efficiency, and engineering advantages.

1. Pile Foundation Definitions

1.1 Driven Pipe Piles

Precast concrete pipes are sunk into the ground using static pressure equipment (jacketing or top-pressing) until reaching design depth or specified terminal pressure values.

1.2 Cast-in-Situ Piles

Formed by drilling, steel pipe soil displacement, or manual excavation to create boreholes. Reinforced with steel cages and filled with concrete. Subtypes include:

Driven cast-in-situ piles
Bored piles
Manual excavation piles

1.3 CFG Composite Foundation

CFG Piles (Cement-Fly Ash-Gravel):
High-strength columns are formed by cement, fly ash, gravel, and sand mixtures. Combined with inter-pile soil and cushion layers to create composite foundations.

2. Construction Processes

2.1 Driven Pipe Piles

Survey positioning → Pile rig setup → Position verification → Pile lifting/insertion → Verticality correction → Static pressing → Splicing → Continued pressing → Final driving → Quality inspection → Head cutting

2.2 Cast-in-Situ Piles

Site leveling → Hole positioning → Casing installation → Rig positioning → Drilling → Drill extraction → Primary cleaning → Inspection → Steel cage placement → Conduit installation → Secondary cleaning → Underwater concreting → Conduit removal → Pile completion

2.3 CFG Piles

Methods:

Long auger drilling
Drill-pump grouting
Vibratory tube sinking

Process:
Survey → Rig positioning → Drilling → Concrete mixing → Pumping & column formation

3. Foundation Types & Cost Analysis

3.1 Classification

Shallow Foundations (<5m depth): Isolated, strip, raft, box
Deep Foundations (≥5m depth): Pile, caisson, diaphragm walls

Common Shallow Foundations

Type	Characteristics	Applications
Isolated	Square stepped design, cost-effective	Light steel structures, equipment
Strip	Linear, adaptable width	Multi-story buildings
Raft	Uniform settlement, high cost	Basement projects
Box	Rigid structure, expensive	High-rises, underground stations

3.2 Economic Comparison

Key metrics:

Cost per kN bearing capacity
Total project expenditure

Case Study: Greenland Century City

PHC pipe piles showed 45.08% cost savings vs. bored piles
13.63% more economical than CFG alternatives

4. Recommended Solution: PHC Pipe Piles

4.1 Advantages

Quality Assurance

Factory-produced (C80+ concrete)
Rigorous QC vs. cast-in-situ defects (necking, mud inclusion)

Design Flexibility

Capacity range: 600–3300 kN
Mixed-diameter configurations for load optimization

Economic Benefits

Lower material costs
57-day total (vs. 115 days for bored piles)

Construction Efficiency

Enables early excavation
Reduces dewatering risks

5. Schedule Comparison

Pile Type	Test Pile	Load Test Wait	Testing	Main Works	Total
Bored Pile	7 days	28 days	20 days	60 days	115d
Driven Pipe	3 days	7 days	7 days	40 days	57d

Conclusion

PHC prestressed pipe piles deliver superior cost-performance ratios, quality control, and project timelines for most mid-to-high-rise developments. Their industrialized production and rapid installation make them the optimal choice for modern construction.

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