Piling in contaminated ground: environmental impacts, regulatory concerns and effective solutions

The paper identifies and discusses potential adverse environmental impacts, and regulatory concerns, that could arise from piling or penetrative ground improvement techniques, when used on land affected by contamination.

A common generic classification of piling and penetrative ground improvement methods is considered and six cases are identified where potential adverse environmental impacts may be created by piling or penetrative ground improvement techniques.

A lack of published data on the scale of impacts caused by piling makes inevitable the application of the “Precautionary Principle” by environmental regulators, but it has been recognised that a rigid application of this principle may lead to unnecessarily restrictive requirements or prohibitions being placed on designers and developers. The need for guidance for designers and developers on how to consider the potential environmental impacts of piling works has also been recognised.

The paper outlines the decision-making framework presented in recent Environment Agency guidance. It assists the foundation designer to assess the environmental risks, select an appropriate piling or penetrative ground improvement method, develop mitigation measures, define quality assurance/quality control and monitoring measures, and justify and document this choice in a format acceptable to the regulator.