ITA publishes Strategy for Site Investigation of tunnelling projects

In a statement, ITA announced: "This study of site investigation for tunnelling projects began with a request from the Executive Council Meeting held in Kyoto, Japan on November, 2001 led by Professor Andre Assis, former President of the International Tunnelling Association (ITA).

"As it is not possible to predefine the ground conditions in detail before a tunnel is constructed geological risks exist on any tunnelling project. The purpose of site investigation is to provide adequate and reliable information in early stages of the project in order to improve the knowledge of the subsoil, assess various design options and choose construction methods that better cope with the identified potential risks.

"Site investigations have to be conducted within the global strategy of project risk management (see "Guidelines for Tunnelling Risk Management ", WG2, 2004) and should follow the ALARP (as low as reasonably practicable) principle to reduce risks - namely geological, geotechnical and hydrogeological risks.

"The level of acceptable risk as defined by the ALARP principle can be specified in different ways depending on the design stage, and the site investigation strategy should take cognisance of this. The effort required during a site investigation (in terms of the scope of investigation and related cost) will vary with the project development, and has to focus on progressively improving the level of knowledge. The effort required at any stage will depend upon the complexity of the project and will have a direct impact on risk mitigation and project cost.

"This document presents the strategy for site investigations based on international best practice, with the aim of maximising the benefit in terms of acquiring knowledge at the right project phase, while avoiding common misleading approaches in terms of investigation effort and responsibility. It is hoped that this document will be a useful guide for future tunnelling projects."

The document can be found through the following link:
http://www.ita-aites.org/en/publications/wg-publications/download/1373_c23b267187260e75764d4a39728328aa