Bond Street, Chelmsford
A large secant bored pile wall, built adjacent to the river Chelmer, for a new city centre shopping mall, requiring the sealing of a deep historic river channel to ensure the basement could be dug safely in the dry.
To prevent a potential flow from the river into the basement, the wall was designed both to accommodate the lateral retained earth pressures, but also using flow nets taking into account seepage gradients to ensure any water into the basement during its initial excavation were non critical and manageable, using the GEO and HYD limit states designated by EC7.
This flow net approach was highly successful as the basement was excavated in the dry and the wall built well within tolerance