Geotechnical & Geoenvironmental Site Investigation Specialists and Consultants

Phase I & Phase II Investigations.

Sub Surface can provide a full site investigation service tailored to satisfy the various regulatory requirements of Planning Departments, Environmental Health departments, the Environment Agency, Building Control departments and property transactions.

This can range from Phase I desk top surveys to full ground engineering master plans incorporating geotechnical foundation design, remediation works, waste licensing and regulatory sign off

  • Phase I

A Phase I investigation or desk study is the collation and review of published information about a site. The Phase I investigation is normally carried out at the start of the site investigation process to characterise the site and inform the remainder of the site investigation. In addition to reviewing the published information a detailed inspection of the site (walkover survey) is normally undertaken. It is an integral part of the phased approach to site investigation.

The benefits of carrying out a Phase I investigation prior to commencing intrusive works include:

  • Allows the efficient targeting of project resources
  • Formulation of the preliminary geological ground model
  • Early identification of potential geohazards
  • Avoid money being wasted on inappropriate intrusive ground investigations
  • Provide early warning of possible delays or budget implications through previously unknown site characteristics
  • Provide information on possible contaminants and anticipated areas of contamination

The requirement for a Phase I investigation is emphasized further in CLR11 (Model Procedures for the Management of Contaminated Land), BS5930 and BS10175.

  • Phase II

A Phase II intrusive investigation comprises obtaining samples and carrying out testing from exploratory holes to obtain information about the ground conditions. The exploratory holes may include hand or machine excavated trial pits, mini rig boring, light cable percussive boring or rotary boring depending on the findings of the Phase 1 investigation and the requirements of the investigation.

The exploratory holes enable a programme of in-situ testing, laboratory testing and monitoring to be undertaken culminating in a report including a revised risk assessment and conceptual ground model.

According to the AGS Guidelines for Good Practice in Site Investigation the objective of the site investigation is to characterise the ground conditions sufficiently to allow safe and economic designs to be developed and to reduce, as far as possible, the occurrence and impact of unforeseen conditions.

We are happy to undertake Phase I and Phase II investigations for any size of project or as a term contract if you have a portfolio of sites to consider.

If you would like a quote please click here.