DRIVEN PILES CASED SHELL-LESS Figure 1-8driven piles 1.4.15 Bored piles Bored piles(Replacement piles)are generally considered to be non-displacement piles a void is formed by boring or excavation before piles is since the bore hole walls do not requires temporary support except cloth to the ground surface.In unstable ground,such as gravel the ground requires temporary support from casing or bentonite slurry.Altemnatively the casing may be permanent,but driven into a hole which is bored as casing is advanced.A diferentechniaue which is still essentially no -displacement,is to intrude grout or a concrete from an augerwhich is rotated into the granular soil,and hence produced a grouted column of soil. There are three non-displacement methods:bored cast-in-place piles, particularly pre-formed piles and grout or concrete intruded piles. The following are replacement piles Augered Cable percussion drilling Large-diameter under-reamedFigure 1-8 driven piles 1.4.15 Bored piles Bored piles(Replacement piles) are generally considered to be non-displacement piles a void is formed by boring or excavation before piles is produced. Piles can be produced by casting concrete in the void. Some soils such as stiff clays are particularly amenable to the formation of piles in this way, since the bore hole walls do not requires temporary support except cloth to the ground surface. In unstable ground, such as gravel the ground requires temporary support from casing or bentonite slurry. Alternatively the casing may be permanent, but driven into a hole which is bored as casing is advanced. A different technique, which is still essentially non-displacement, is to intrude, a grout or a concrete from an auger which is rotated into the granular soil, and hence produced a grouted column of soil. There are three non-displacement methods: bored cast- in - place piles, particularly pre-formed piles and grout or concrete intruded piles. The following are replacement piles: Augered Cable percussion drilling Large-diameter under-reamed