Secant Wall Design and installation for storm water new tank shaft.
Provided a low vibration cast in-situ solution
Early contractor involvement allowed a combined secant wall and grouting solution to be developed for scheme.
The project
The construction of a new storm water tank at Southern Waters’s Havnt Sewage Treatment Works (STW).
The challenge
To provide a design and install solution for the pilng works to create the new shaft. The soil profile consisted of up to 4-5m of made ground and firm clays and sands overlying weathered and competent chalk. One of the key risks which needed to be mitigated was the ability to bore this chalk whilst managing the high water table encountered.
The solution
Rotary bored piling was adopted as the piling solution. Keller selected a 1180/1050mm diameter pile to a pile length of 18.5m. Early contractor involvement allowed working platform and site logistics to be effectively managed to maximise efficiencies on site. Review of design information allowed the reinforcement to be minimised allowing saving in cost and carbon footprint. All works were completed safely and within programme.