What is a Site Investigation?

What is a Site Investigation?

A Site Investigation is an intrusive investigation to assess ground conditions and general pattern of the strata beneath a site for Geotechnical and Environmental purposes. All Site Investigations should be carried out accordance with the UK Specification for Ground Investigation (Second Edition), British Standard Code of Practice BS5930 and British and European Standard BS EN 1997-2 (EC7).

The aim of a Site Investigation is  to satisfy our Clients’ requirements along with, where necessary, the various regulatory requirements of Planning Departments, Environmental Health Departments, Building Control Departments, the Environment Agency and property transactions.

Site Investigation Services

Sub Surface offer a comprehensive range of Site Investigation services including (but not limited to):

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What are the Different Types of Intrusive Site Investigation Techniques?

There are a number of different types of intrusive Site Investigation techniques of which each technique has its advantages and limitations. The technique used will be determined by the anticipated ground conditions and the Clients’ requirements. Some of the most common methods Sub Surface use include:

What Pre Site Investigation Surveys do Sub Surface offer?

 Prior to any Site Investigation, if required, we offer a range of surveying options, including:

• CAT Scan
• Underground Utility Plans Search
• Ground Penetrating Radar (GPR) Survey
• Topographic Survey
• Preliminary Unexploded Ordnance (UXO) Risk Assessment
• UXO Risk Assessment
• Ecological Survey
• Archaeological Survey

What happens after the Site Investigation (Geotechnical)?

Following the Site Investigation, our Geotechnical and Geo-Environmental Engineers will subsequently log the samples in accordance with BS EN ISO 14688-1 and BS EN ISO 14689-1.

A Sub Surface Contracts Manager will then draw up a laboratory testing schedule based on the ground conditions encountered and the project requirements. Sub Surface Laboratories are fully equipped to carry out soil testing to BS1377 and rock testing to ISRM 1974-2006.

Following completion of the laboratory testing, a professionally qualified Engineer will write a Factual report, Interpretative Report or Ground Investigation Report (GIR).

What is included in a Ground Investigation Report (Geotechnical)?

All our Ground Investigation Reports are written to the current British Standards, Eurocode 7 Standards and National House Building Council (NHBC) Standards. Every project and development is different, however for a typical Foundation Design, our Ground Investigation Report with interpretative would include:

• Engineer Logs
• In-situ Testing
• Laboratory Testing
• Shrinkage and swelling potential of clays/silts (cohesive strata)
• A preliminary Foundation Design
• Safe Bearing Pressures and/or Pile Loads
• Floor Slab Construction
• Groundwater Information
• Concrete Classification – Design Sulphate (DS) Class and Aggressive Chemical Environment for Concrete (ACEC) Classification

Additional items commonly incorporated within our Interpretative Reports include:

• A full Geology and Mining Appraisal
• Earth Pressure Coefficients for Retaining Walls and Basements
• CBR Values for Roads, Car Parks and Hardstandings
• Percolation and Soakaway Tests
• Settlement Calculations
• Slope Stability Analysis
• Contamination Analysis
• Landfill Gas Assessment

It should be noted that when developing a brownfield site and many greenfield sites, the Local Authority generally apply a prerequisite on the Planning Conditions requiring a Phase 1 Desktop Study prior to a Phase 2 Ground Investigation.

Why Sub Surface?

Sub Surface will design a site specific Site Investigation to satisfy the Client’s project requirements and any regulatory authorities. Our network of local offices across the UK allows us to provide a cost effective service nationwide. Sub Surface cater for all project types and sizes from small residential extensions to large corporate infrastructure projects. View our Case Studies.

Established in 1972 and with over 45+ years’ experience, Sub Surface has built a reputation as one of the leading and highly regarded independent Site Investigation Specialist, Geotechnical and Environmental Consultancy companies in the UK.

Our highly experienced and professionally qualified staff include Chartered Civil Engineers, Chartered Geologists, Chartered Environmentalists and a Qualified person under CL:AIRE DoW:CoP. Sub Surface and their employees are also members of professional institutions and industry bodies including the Institute of Civil Engineers (ICE), Institution of Environmental Sciences (IES), The Geological Society, Association of Geotechnical & Geoenvironmental Specialists (AGS) and British Drilling Association (BDA).

All our Site Investigations are carried out to the relevant British and European Standards including, BS 5930 and all our drillers have an NVQ in Land Drilling from the British Drilling Association. We are also accredited by Constructionline and CHAS.

The importance of a Site Investigation?

An integrated Ground Investigation Report with interpretation is generally required to satisfy the various regulatory requirements of Planning Departments, Environmental Health Departments, Building Control Departments and the Environment Agency.

A professional and comprehensive Site Investigation limits the risk of unexpected ground conditions during the development, which could cause significant cost implications and time delays, resulting in the whole project becoming uneconomically viable.

Failure to undertake a comprehensive Site Investigation could result in significant risks to: the health and safety of site workers, end users and general public; the environmental risks to human health, vegetation and controlled waters; and the stability of structures and services. All of which will be the liability of the site owners and/or developers.

What are the Limitations of a Site Investigation?

The historical, geological and environmental setting of the site can be assessed prior to arrival on site to give a good indication of the anticipated ground conditions. However, the ground conditions encountered during the site investigation could be completely different, resulting in additional site investigation works being required.

It should also be appreciated that only a small proportion of the area to be developed is likely to have been investigated and consequently the recommendations made and opinions expressed in our interpretative reports can only be applied to such conditions as were encountered in the exploratory holes.

What is the Cost of a Site Investigation?

No fixed price can be put on a Site investigation, as the cost is dependent on the project requirements, the size of the site, the anticipated ground conditions and the intrusive techniques involved. Sub Surface use their experience in the local area and published geological information to provide our Clients with an accurate and cost effective quote.

How can I Get a Quote?

If you would like a quote, please fill in our Quick Contact Form or contact your Regional Sub Surface Office (regional map via link) and email the following information (where necessary/available):