Sheet-pilings are a particular group of piles formed by isolated elements fixed onto the ground, yet connected one another in order to form an uninterrupted bulkhead, sideward pressure resistant.
Sheet-pilings can be built in wood, iron, (Larssen type) or in reinforced concrete, either built out of the structure or casted onto the ground by special buckets creating rectangular panels , 2-3 mm. wide and 50 to 80 cm. thick. These panels form an uninterrupted bulkhead, a real concrete wall, remarkably deep, of constant and non-stop sections between the joints.
The choice of  sheet-pilings  to be used mainly depends on the  work  to be performed.
Presently, sheet-pilings are used not only as temporary works which allow the draining and the digging of the soil but also as load supporting frames for foundation works as well as renewal of works undermined by water erosion.
 A particular type of diaphragm are piles diaphragm with permeating elements carried out with beating equipment and with the same technique used for the isolated piles.
In this case, drillings are carried out at a distance between the axle and the lower axle to the hole diameter and  the joint connecting one element to another is fastened by intermediate drillings resulting by the two injected elements, themselves.
These particular kind of  diaphragms  can replace iron or reinforced concrete sheet-pilings especially in case of gravel or pebbles soils or when sheet-pilings technique is difficult to be performed.
Finally, bulkheads performances are quite cheap.

Bulkhead piles can be used as definitive works in the following conditions:

a.     foundations and bridges abutments;
b.    renewal works of sub-foundations in works undermined by water;
c.    consolidations of foundations damaged by subsidence or material decomposition;
d.    crossbeams on rivers as waterproof barrier in hydraulic works ;
e.    protection of banks  and other works subject to water erosion.