Simplex Westpile has long been renowned for its expertise in Rotary and CFA Piling and its innovative approach to the design and construction of retaining walls.
Secant piled walls are predominately constructed so that the female piles contain lower strength material than the concrete in the male piles. Walls are installed as hard/firm or hard/soft depending upon the specified requirements for the secant wall and the basement lining wall.
Firm female piles are constructed using a weak concrete mix that fills the gap between the hard male piles. The concrete mix is designed to be soft enough to allow the male pile to be cut into the adjacent piles and often achieves no more than 8-10N/mm2 at 56 days.
Soft female piles are formed with a weak bentonite cement grout and provide less resistance to the construction of the male piles.
In Hard/Firm and Hard/Soft Secant Piled Walls only the male pile is reinforced.
Technique:
Secant piled walls are constructed such that space is left between alternate primary or ‘female’ piles for the subsequent construction of secondary or ‘male’ piles. Construction of ‘male’ piles involves boring through the concrete in the ‘female’ piles in order to key ‘male’ piles between them.