Understanding Different Piling Processes with a focus on secant piling

For any concrete structure to be well constructed, it needs to have a firm foundation with a very firm underground structural base. This is to make sure that the heavy building is supported adequately. Piling processes are responsible for this firm structural base.

Piling processes are techniques used by contractors to create deep structural / building foundations. During these processes, wood piles, steel or concrete are driven and embedded into the soil deep in the ground. Eventually, the foundation levels of buildings are made very strong to offer maximum support.

Before the processes begin, factors such as project scope, size and capacity, under the ground soil condition, rigging space need to be considered. A deep foundation requires strong soil layer for it to have the capacity to offer the best support.

Precast concrete piles, steel sheet piles, vertical wood columns and timber piles are the most common piling materials.

Piling processes involve driving or drilling your preferred type of piles into the ground in order to set up a firm foundation, able to support the intended building’s load. Civil engineers should play their roles in construction by engaging piling processes which result to firm foundations and therefore firm structures.

There are piling processes of different kinds. Which kind is undertaken is a question of which specific project is underway. Civil Engineers, housing developers and contractors use different piling processes for establishment of housing development projects, big commercial projects, marine projects and road / retail projects among others.

Piling processes differ from each other on the basis of the chosen material and the process used. As mentioned above the two main techniques are mainly drilling and driving piles.

Directional Drilling technique: This technique uses boring method to drill into hard ground to insert piles. These piles are also referred to as CIDH meaning Cast-in-Drilled-Hole piles. Drilled piles are: under-reamed piles, Auger Cast piles, pier & grade beam foundation, mini piling and tripod piling.

Driving technique: It is done by a pile driver which is a mechanical device utilized to drive or insert your preferred piles into the ground. There is also a new state-of-the-art hammer utilized to insert or drive piles, mostly timber or pipes into the soil.

Bored piles are cost effective and efficient in construction of long-term or short-term walls for retention. They are used during construction of building basements, substructures near existing structure which may require restraining. Piling helps to reduce too much excavation and helps in regulating ground shaking or movement.

Discussed below are the three piling processes

Secant Piling

This type of piling is the most functional and efficient of them all. This is because the constructing equipment used for secant piling include heavy-duty CFA auger featuring rotary cutting heads. The piling process is similar to the one for interlocking piles. The difference is that secant piling engages strong concrete mix just as the one for primary piles. The soft or secondary piles are reinforced in the same way the primary piles are.


When secant piles are embedded together, the end result is a well formed retaining wall for terraces or excavation pits. Secant piling can be applied with different requirements of diameter, material, placement, formation to meet different unique construction needs.

Civil engineers can use secant piling to construct ground water barriers, foundations and retaining walls.


It has various advantages over other piling processes namely:


– Improved structural toughness compared to others constructed through other processes.

– Improved flexibility in terms of construction alignment

– Can be set up on difficult / hard ground

– Good closely installed columns like 3 – 5 inches from already existing structures

– Usable in areas with high water table conditions

– Reduced noise during construction

– Contiguous Piling

This process is preferable for retention of cohesive and sub-soil and in places where the level of underground water is lower past the ultimate excavation depth. In contiguous piling, the piles diameters fall between 450mm to 900mm and are inserted at the middle of piles with the range of 50 and 1000mm. This means that gaps measuring around 15mm to 100mm are left after installation.

Interlocking Piling

This process is almost the same as contiguous piling but here the gap between piles is occupied by soft piles of non-reinforced not-so-strong concrete mix placed a layer below the eventual excavation depth level. This type of piling ensures that less amount of water goes past subsequent excavation.


Generally, piling processes are important for structural support purposes. Specifically, secant piling is a crucial economical solution for most civil structural shoring walls offering unmatched support of structural foundations as well as ground water regulation problems. In other words, secant piling process has several civil applications among them structural walls and dewatering solution and shoring.