1,Micropiles:
Micropiles, also called mini piling pipe, are used for underpinning. Micropiles are normally made of steel with diameters of 60 to 200 mm. Installation of micropiles can be achieved using drilling, impact driving, jacking, vibrating or screwing machinery.
2,Tripod Piles
The use of a tripod rig to install piles is one of the more traditional ways of forming piles, and although unit costs are generally higher than with most other forms of piling, it has several advantages which have ensured its continued use through to the present day.It can work in restricted sites (particularly where height limits exist), it is reliable, and it is usable in almost all ground conditions.
3，Sheet Piles
Sheet piling is a form of driven piling using thin interlocking sheets of steel to obtain a continuous barrier in the ground. The main application of steel sheet piles is in retaining walls and cofferdams erected to enable permanent works to proceed.
4,Suction Piles
Suction piles are used underwater to secure floating platforms. Tubular piles are driven into the seabed (or more commonly dropped a few metres into a soft seabed) and then a pump sucks water out the top of the tubular, pulling the pile further down.
The proportions of the pile (diameter to height) are dependent upon the soil type: Sand is difficult to penetrate but provides good holding capacity, so the height may be as short as half the diameter; Clays and muds are easy to penetrate but provide poor holding capacity, so the height may be as much as eight times the diameter. The open nature of gravel means that water would flow through the ground during installation, causing 'piping' flow (where water boils up through weaker paths through the soil). Therefore suction piles cannot be used in gravel seabeds.
5,Adfreeze Piles
In extreme latitudes where the ground is continuously frozen, adfreeze piles are used as the primary structural foundation method.
Adfreeze piles derive their strength from the bond of the frozen ground around them to the surface of the pile. Typically the pile is installed in a pre-drilled hole 6"-12" larger then the diameter of the pile. A slurry mixture of sand and water is then pumped into the hole to fill the space between the pile and the frozen ground. Once this slurry mixture freezes it is the shear strength between the frozen ground and the pile, or the adfreeze strength, which support the applied loads.
