Bored Piles | CFA Bored Piles | Driven H Piles | ||
Advantages | Bored pile are used to support multi-story building or bridges which can producing heavy vertical loads | They are quick to install and have no requirement for temporary or permanent casings | Driven piles are driven to a set in variable site conditions to achieve uniform minimum capacity with high reliability | |
Methodology | Pile drilled / soil removed and replaced with reinforced concrete | Auger drilled into ground and replaced with concrete as the auger is removed | Steel section driven into the ground | |
Design | Effect on adjacent ground | No displacement of the soil but the potential for relaxation / softening adjacent ground, dependant upon the soil and bore support used | Typically no displacement with good construction controls Localised densification of loose non-cohesive soils. | Small cross sectional area and hence minimal soil displacement or potential improvement |
Typical size ranges | 450-2500mm diameter | 450 – 1200 mm diameter depths up to 32m | 150 – 350 UC’s, UBPs | |
Capacity - Shaft friction | Medium | Medium | Medium | |
- End bearing | Very high with enlarged base | Medium | High | |
- Structural | Very high structural capacity and stiffness achievable | Cage insertion can limit tensile and flexural capacity at depth | Driving stresses often govern the steel section required | |
Durability | Conventional concrete in the ground design Permanent liner in highly aggressive conditions | Conventional concrete in the ground design | Sacrificial thickness of steel above low groundwater level | |
Construction | Typical / Plant | Hydraulic or crane mounted piling rig, handling crane, casing, vibro with powerpack and / or drilling support fluid plant | Hydraulic piling rig, concrete pump and possible handling crane | Crane, vibro hammer or hydraulic hammer with powerpack or drop hammer and leaders or guide frame |
Piling productivity | 16m deep - 600dia @ 2No/day in soft material including a 3m soft rock socket depth. Detailed production rates | 16m deep - 600dia @ 11No/day in soft material including a 3m soft rock socket depth | 16m deep - 350 UC’s @ 22No/day in soft material | |
Material to Plant | Concrete, reinforcement cages and method dependant material | Concrete and reinforcement cages | Steel sections | |
Materials storage | Casing and cage lay down area | Cage lay down area | H pile lay down area | |
Noise | Machine only unless driven casing | Machine only | Yes, if vibro used hammer used to obtain pile set | |
Vibration | No, unless driven casing used | No | Yes | |
Spoil | 100% Nett volume | 100% Nett volume | None | |
Other | Plunged columns can be placed into the top of the pile to structural positional tolerances | Fast installation process with real time monitoring systems for construction control and records | Full strength welded splice used at connections Predrilling can be used to overcome obstructions | |
Driven Tubes Piles | Precast Concrete Piles | Vibro replacement | ||
Advantages | They are ideally suited for marine and other near shore applications with a very high end bearing capability | Precast driven piles can be environmentally friendly when construct temporary trestles in wetland | Stone piles are a very effective technique, for resolving issues with liquefiable soils, that fall within the typical grain size range | |
Methodology | Tube driven using external or internal hammer and filled with reinforced concrete | Pre cast section driven into the ground | Soil displaced or removed and replaced with stone | |
Design | Effect on adjacent ground | Large displacement of plugged tubes resulting in densification of non-cohesive soils and enhanced capacity | Large displacement resulting in densification of non-cohesive soils and enhanced capacity | Large displacement with densification of non-cohesive soils surrounding the stone column which enhances the capacity |
Typical size ranges | 350 – 750 mm diameter | 250 – 600 mm square | 600 – 1200 mm diameter | |
Capacity - Shaft friction | Medium | Medium | Low | |
- End bearing | Very high | Very High | Low | |
- Structural | Tubes can be reinforced concrete filled to enhance capacity | Lifting, driving and jointing can limit capacity | Stone quality & confinement in the soil limit the capacity | |
Durability | Sacrificial thickness of steel and internal reinforced concrete | Conventional concrete in the ground design Review potential corrosion at joints | Weathering / degradation of stone typically not an issue | |
Construction | Typical / Plant | Crane, vibro hammer or hydraulic hammer with powerpack or drop hammer, leaders or guide frame | Crane, hydraulic hammer with powerpack or drop hammer, leaders or guide frame | Crane, vibro probe with power pack, water pumps, compressor and front loader |
Piling productivity | 16m deep - 600mm Dia piles @ 22No/day | 16m deep - 300mm square piles @ 20No/day | 12m deep @ 6No/day in soft material | |
Material to Plant | Steel tubes, reinforcement cages and concrete | Precast concrete piles unless manufactured on site | Stone | |
Materials storage | Tube and cage lay down area | Precast pile lay down / curing area | Stone stockpiles | |
Noise | Yes if top driven but limited if bottom driven | Yes | Machine only | |
Vibration | Yes | Yes | Yes | |
Spoil | None, but ground heave possible | None, but ground heave possible | 20 - 100% Nett volume | |
Other | Predrilling can be used to overcome obstructions Enlarged bases can be formed to enhance capacity | Variable pile founding depth can lead to high wastage levels and jointing expensive | Top feed “Wet” process requires water circulation system and settlement ponds to contain silts | |
Diaphragm Wall | ||||
Advantages | Sheet piles are best suited for the following applications temporary retaining walls, cofferdams and other temporary structures | This is a permanent solution which provides increased wall stiffness compared to sheet piles | Diaphragm walls tend to be used for retaining very deep excavations as they can be designed to take very high structural loads | |
Methodology | Clutched sheet piles driven into position. | A series of piles installed so that they overlap to form a wall. | A series of interlocking reinforced concrete panels. | |
Construction | Establishment | Cranes, vibros and hammers and / or pile jacking plant | 50-60T self erecting hydraulic drilling rigs and handling crane. | 50T crane + grab, handling crane, mud conditioning plant, mud storage |
Piling productivity | 16m deep - 600mm wide sheet piles @ 22No/day (in clay or sand materials) Detailed production rates | 16m deep - 600dia @ 4No/day in soft material including a 3m soft rock socket depth. Detailed production rates | 16m deep by 800mm wide @ 14-40m3/day of completed wall per rig per day | |
Materials to site | Sheet Piles | Concrete, reinforcement cages | Bentonite, reinforcement cages or concrete panels | |
Work face access | Plant & Materials delivery | Plant & Materials delivery | Plant materials and pipelines for mud circulation | |
Noise | Yes, unless jacked in | Machine only | Machine only | |
Vibration | Yes, unless jacked in | No | No | |
Spoil | No | 100% nett volume | 100% nett volume | |
Product | Wall Movement | Flexible, can be increased with clutched king piles. More props or anchors can be used to reduce movements | In-situ wall with ground supported throughout construction. Very stiff. | Ground supported throughout excavation. Stiffest option given wall thickness |
Watertightness | Good with joint treatment | Groundwater control over pile length and satisfactory performance with some seepages | Excellent over full depth of the wall with waterbar across panel joints. | |
Connections | Welded below capping beam level | Drilled & grouted bars into piles, shear & bending capacity possible | Full moment & shear connection via box-out and pull-out bars | |
Durability | Internal painting and sacrificial thickness of steel | Conventional concrete in the ground design. Internal lining for long-term seepage | Conventional concrete in the ground design. No internal lining necessary | |
Load Capacity | Low end bearing capacity | Capacity can be enhanced by increasing the length of some piles | Wall has a large bearing area and individual panels can be extended | |
Soldier Pile Wall | Soilmix/Slurry Wall | |||
Advantages | Soldier pile and lagging walls are the most inexpensive systems compared to other retaining walls. They are also very easy and fast to construct | Low cost and speed of construction for temporary and permanent retaining walls and soil support | Excellent resistance to contaminated groundwater. They have abilityto adapt to ground movements such as earthquakes | |
Methodology | Constructed using piles timber infill panels (timber, steel or concrete) | Series of bored piles installed relatively close together with shotcrete arches | Steel or precast concrete elements placed in fluid soilmix / slurry | |
Construction | Establishment | 50-60T self erecting hydraulic drilling rigs and handling crane | 50-60T self erecting hydraulic drilling rigs, handling crane and concrete pumps | 50T crane + grab / CSM, handling crane / grout plant with screw feed silos, high pressure pumps |
Piling productivity | 16m deep - 300mm square piles @ 18No/day | 16m deep - 600dia @ 4No/day in soft material including a 3m soft rock socket depth. Detailed production rates | 16m deep by 800mm wide @ 20-50m3/day of completed wall per rig per day | |
Materials to site | Concrete, reinforcement cages, steel or precast concrete panels | Concrete, reinforcement cages | Cement, bentonite, steel or precast concrete panels | |
Work face access | Plant & Materials delivery | Plant & Materials delivery | Plant, materials and pipeline delivery of slurry | |
Noise | Yes, if driven sections | Machine only | Machine only | |
Vibration | Yes, if driven sections | No | No | |
Spoil | Dependant on installation method | 100% nett volume | 30%-80% Nett volume | |
Product | Wall Movement | Ground unsupported allowing relaxation prior placement of panels and backfilling Stiffness depends on structural section and backfill compaction | Ground unsupported allowing relaxation prior to concrete Finished product stiff | Ground supported with stiffness dependant on steel section. Precast panels can increase stiffness. |
Watertightness | Permeable with no groundwater control below excavation. Seepages long term | Permeable until shotcrete in place with no groundwater control below. Seepages long term | Good temporary performance due to replacement with CB slurry but some seepages | |
Connections | Numerous connection options dependant on materials used | Drilled and grouted bars into piles, shear and bending capacity possible | Welded to steel sections, shear & bending capacity possible. | |
Durability | Conventional concrete in the ground design or sacrificial steel thickness given long term seepage potential | Conventional concrete in ground design | Sacrificial thickness of steel and internal lining wall for long-term groundwater seepage | |
Load Capacity | Capacity can be enhanced by increasing the length of piles. | Capacity can be enhanced by increasing the length of some piles. | Capacity limited by penetration of steel beams | |
