Wigan Water Treatment Plant
Leading geotechnical specialist Bachy Soletanche Limited (BSL) has demonstrated its innovation and organisation in equal measure during ongoing piling work at a waste-water treatment plant in Wigan. Due for completion on 11 July, the project would usually require large-diameter auger (LDA) piling, but BSL has managed to utilise the faster, more cost-efficient continuous flight auger (CFA) process.
Richard Mercer, Contracts Engineer at Bachy Soletanche explained:
“The project at Wigan has involved the construction of a secant wall and bearing piles for two new filter beds and their associated structures. This work would usually involve an LDA piling solution, but because the site is located on clay rather than rock, we have been able to use CFA, which has resulted in a significant reduction of the time required to complete the work.”
In total, the project involves the construction of 121 CFA piles to create a secant wall up to 900 millimetres in diameter, and 16.5 metres deep. An additional 175 CFA bearing piles are also being constructed with a diameter of 450 millimetres and a depth of 17.5 metres.
BSL began work on 26 May and careful planning and organisation has meant piling has remained on schedule throughout the work. However, due to the size and nature of the piles, BSL did need to call on some added muscle. Richard Mercer commented:
“Although the ground of the site is relatively soft, allowing us to use CFA, the scale of the work still goes beyond the average CFA project. In order to provide the required torque for the work, we mobilised a CM 700 rig to accompany the more common CM 48 rig.”
“Although the programme was tight, careful planning and organisation has meant we are on schedule for completion on July 11th.” He added.