Concrete @ your Fingertips The piles may be constructed so that they virtually touch each other (contiguous). The gaps between the piles can be grouted to form a watertight retaining wall. Alternatively (secant piles) every other pile may be constructed, with their centres less than two diameters apart.
Why might contiguous piles have been used as dividing walls instead of secant piles?
The presence of footings of adjacent buildings and underground utilities on a site make contiguous pile wall the ideal choice for supporting an excavation. Contiguous piled walls have a faster speed of installation when compared with secant piled walls.
What is the difference between sheet piling and secant piling?
The advantages of secant pile walls are that, compared to sheet piling methods, they can provide greater wall stiffness. They are also capable of being installed in low headroom and in difficult ground conditions.
When would you use secant piles?
Secant Pile Walls are usually installed as retaining structures and support systems for deep foundations, retaining elements and at the same time load-bearing walls and deep foundations for engineering constructions (e.g. walls and foundations of underground storeys, stand-alone and framed bridgeheads, etc.).
What is contiguous bored piles?
Contiguous bored pile walls are formed by constructing piles using the CFA, LDA or CSP technique. Piles are constructed so that they virtually touch each other with typical gaps of between 50mm-150mm. The soil in the gaps is exposed during excavation and can if necessary be grouted or sealed to form a watertight wall.
What is bored pile?
Bored piles are cylindrical bodies made of concrete (with or without reinforcement) which are installed in the ground by a variety of methods. They transmit high structural loads into lower, load-bearing soils.
What is contiguous bored pile wall?
Contiguous piled walls consist of a row of successive unconnected cast-in-situ concrete piles constructed with small gaps between the adjacent piles, formed using CFA or rotary bored piles (replacement piles techniques). …
What is contiguous pile wall?
Contiguous pile walls consist of piles arranged in a line typically with a 150mm gap between the piles. Where required the soil between the piles can be stabilised using grouting techniques if necessary, either before or after pile installation.
What is Secant bored pile?
A Secant Piled Wall is a retaining wall constructed for ground retention prior to excavation. The wall is formed by constructing alternating primary (female) and secondary (male) piles where the secondary piles partially cut into either side of the primary piles in order to form a continuous impervious structure.
What is contiguous bored pile?
What are secant bored piles?
What are contiguous piles used for?
Contiguous piled walls are used in dry and cohesive soils and are often the quickest and more economic method of constructing retaining walls. In certain ground conditions it may be necessary for the design to incorporate temporary props or ground anchors to provide additional lateral support to the wall.
What is the difference between contiguous and secant piling?
This is common when constructing basements, underpasses or cut and cover tunnels. If the piles are constructed so that they are touching they are called contiguous piles, and they can then be grouted to form a watertight wall. Secant piling is when there is no gap between piles as a wall is made of interlocking bored piles.
Do secant piles need to be reinforced?
In circular secant pile shafts, it might be possible to only have unreinforced piles if a compression ring action is ensured throughout the secant pile wall perimeter. Tangent pile walls, in contrast to secant pile walls do not interesect. As a result, all tangent piles need to be reinforced.
What is the difference between sheet pile and Secant pile walls?
Pile overlap is typically in the order of 3 inches (8 cm). In a tangent pile wall, there is no pile overlap as the piles are constructed flush to each other. The main advantages of secant pile walls are: 1. Increased construction alignment flexibility. 2. Increased secant pile wall stiffness compared to sheet piles.
What is a bored pile wall?
A bored pile wall is when a wall is constructed using this method. There are three bored pile wall systems: The type of bored pile wall will depend on a variety of factors including surrounding soil type, construction time and cost. Here, we’ll look at each bored pile wall system in a little more detail.
