Sheet Pile
Sheet pile are generally made of steel or timber. These piles are driven into the ground for either separating members or for stopping the seepage of water, they are not meant for carrying the vertical load. Sheet piles are sections of sheet material with interlock edges that are driven into the ground of providing earth retention and excavation support. However, sometimes reinforced cement concrete sheet piles are also used. The use of timber piles is generally limited to temporary structures in which the depth of driving does not exceed 3m. For permanent structures and for depth of driving greater than 3m, steel piles are more suitable.
Types Of Sheet Pile
- Cantilever Sheet Pile
- Anchored Sheet Pile
1. Cantilever Sheet Pile
Cantilever sheet piles are further divided into two types:
A. Free Cantilever Sheet Pile
It is a sheet pile subjected to a concentrated horizontal load at its top, there is no backfill above the dredge level. The free cantilever sheet pile derives its stability entirely from the lateral passive resistance of the soil below the dredge level into which it is driven.
B. Cantilever Sheet Pile
A cantilever sheet pile retains backfill at a higher level on one side. The stability is entirely from the lateral passive resistance of the soil into which the sheet pile is driven, like that of a free cantilever sheet pile.
2. Anchored Sheet Pile
Anchored sheet pile are held above the driven depth by anchor provided at a suitable level. The anchor provide forces for the stability of the sheet pile, in addition to the lateral passive resistance of the soil into which the sheet piles are driven. The anchored sheet piles are also of two types:
A. Free-Earth Support Pile
An anchored sheet pile is said to have free-earth support when the depth of embedment is small and the pile rotates at its bottom tip. Thus there is no point of contraflexure in the pile.
B. Fixed-Earth Support Pile
An anchored sheet pile has fixed earth support when the depth of embedment is large. The bottom tip of the pile is fixed against rotations. There is a change in the curvature of the pile, and hence an inflexion point occurs.
