Over the last few decades CONSTRUCTION of retaining walls in urban areas has grown significantly, as a result of territorial and economical development of the cities. In most cases, retaining walls are deep structures with the existence of groundwater level because urban areas are often at a few meters above sea level. Furthermore, CONSTRUCTION of retaining walls in cities, introduce special problems as a result of being directly in touch with urban elements and citizens.
In situ pile retaining walls are very popular due to their availability and practicability.
There are different types of pile walls contiguous (intermittent) bored pile CONSTRUCTION, (spacing between the piles is greater that the diameter of piles)
In these conditions, for deep borings and with the existence of groundwater level, diaphragm walls and secant pile walls are the only feasible retaining walls in urban areas. Secant pile walls are usually used in hard ground, where it is not possible to install diaphragm walls, and in rocks, and it is technically possible to install secant pile walls in a extensive range of grounds.
Secant bored pile walls are formed by keeping spacing of piles less than diameter.It is a watertight wall and may be more economical compared to diaphragm wall in small to medium scale excavations due to cost of site operations and bentonite plant.