Frequently Asked Questions (FAQ) Geotechnical

Earth Environmental & Geotechnical are an environmental, geological, and geotechnical practice that offer an expert driven, cost effective and pragmatic service to clients. Here we answer some of the questions we are often asked, to help you understand what support your development needs.

Frequently Asked Questions

The term geotechnical refers to the practical applications of geology, typically for the purposes of civil engineering and mining. Most geotechnical companies take this science and apply it to designing earthworks and structure foundations, monitoring site conditions, and foundation construction. Generally, these projects involve subsurface site investigation of bedrock, soil, and fault distribution.

Geotechnical investigation is a process in which the physical properties of a site are assessed for the purpose of determining which uses of the site will be safe. Before land can be developed or redeveloped, geotechnical investigation is often required. This process is also required or recommended in the wake of incidents like flooding, the emergence of foundation cracks on land which was thought to be solid, and so forth. The goal of such investigation is to confirm that the land is safe to build on. Here we answer some of the questions you may have on Environmental and Geotechnical services.

FAQ

What is a phase 1 desk study report?

A Phase 1 Desk Study is an interpretive report that details the likely presence of any contamination within the subsurface, and the potential risks that this may present to future site users, developments and the immediate environment.
The Phase 1 Desk Study collates information from a wide range of sources relating to the site setting and its previous historical uses. A Phase 1 Desk Study Report should always precede any ground investigation. Ideally it should also be accompanied by a walk over survey conducted by an experienced practitioner. to provide greater certainty in the report findings.

Why do I need a Phase 1 Desk study Report?

If you are planning on developing a site you will generally need a Phase 1 Desk Study Report as part of your Planning application set out by the Local Authority Planning Department.

Or you may be planning on purchasing a property or site for development, as part of the Property Transactions (Due Diligence) it is prudent to complete a Phase 1 Desk Study Report.

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What is included in a Phase 1 Desk Study Report?

A Phase 1 Desk Study Report collates information from a variety of sources.

At Earth Environmental & Geotechnical this may include.

  • Ordnance Survey, Town Plans, and Aerial Photographs to allow us to assess existing and former land uses
  • Flood risk potential by reference to Environment Agency mapping and British Geological Survey records
  • Solid and drift geology by reference to British Geological Survey mapping and borehole index
  • Groundwater vulnerability from Environment Agency classification of aquifer status
  • Earthquake records within 1km of the site by reference to British Geological Survey records
  • Consultation with local authority Environmental Unit
  • Assessment of potential subsidence issues from an examination of geological maps, boreholes index, and walkover survey
  • Assessment of slope stability for relevant areas during the walkover survey
  • Brine Subsidence search for sites within relevant areas
  • Active and historical surface and underground workings based on published information and internal records
  • Coal Authority Mining Report if the site is within the Mining District
  • Active and closed landfill search within 500m of the site boundary based upon local authority and Environment Agency records
  • Radon gas potential with reference to Heath Protection Agency records
  • Preliminary Ecological Assessment based upon walkover survey and references to English Nature database
  • Petroleum Licencing Officer record search for sites with evidence of petroleum storage
  • Planning history of the site by examination of local authority portal
  • Preliminary Invasive Plant survey based on walkover survey
  • Preliminary Archaeological Assessment based on reference to National Monument Records

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What does a Phase 1 Desk Study Report look like?

The attached PDF shows an example of a Phase 1 Desk Study Report.

For further information on Phase 1 Desk Study Reports please click here.

What’s the difference between Phase 1 Desk Study Report and a Phase 2?

A Phase 2 assessment consists of an Intrusive Site investigation with quantitative risk assessment. Depending on what is highlighted in this assessment, a subsequent remediation strategy and verification report may then be required.
A Phase 2 assessment is only needed if it is identified in the initial Land Contamination Assessment or if it is part of the conditions the Local Planning Authority have attached to the planning approval.

For more information on Phase 1 Desk Study reports please click here

What is a Site walkover?

The site walk overs form an integral part of our Phase 1 Desk Study reports.  The purpose of the survey is to basically see a site in the flesh, to identify potential sources of contamination.During the walkover survey, we will assess areas identified within the desk study as potential development issues, environmental and cost liabilities. We also highlight potential remedial options or management considerations.
Following the desk study and walkover survey, a Site Conceptual Site Model can be developed. This will allow for environmental and geotechnical hazards to be individually assessed.  Any potential pollutant linkages can then be prioritised for any future Phase 2 Site Investigation.

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What is a Plate Bearing Test?

The Plate Bearing Test (or Plate Loading Test) is an in-situ field test used to find the ultimate bearing capacity of rocks and soils and predict the settlement beneath an imposed load.

An example of a Plate Bearing Test click here

Earth Environmental & Geotechnical  offer Plate Bearing Test (or Plate Loading Test)  for more information please click here

Why would I need a Plate Bearing Test?

Design engineers need to know the bearing capacity of soil underneath the proposed construction when designing the traffic surface or shallow foundations.The Plate Bearing Test (or Plate Loading Test) is also useful for construction sites to establish ultimate bearing capacity and settlement of the ground for working platforms, crane outrigger pads and piling mats. At Earth Environmental & Geotechnical our engineers will advise on the plate size required to match the design load and reaction load required (i.e. size of excavator).

For further information on Plate Bearing Test Reports please click here

What does a Plate Bearing Test report Look like?

Here is an example of a Plate Bearing Test (or Plate Loading Test). The objective of the test is to obtain a load-settlement curve of a soil at a particular depth, to estimate the ultimate bearing capacity of the foundation.

Example of Plate Loading Test

The load intensity and settlement observation of the plate load test are plotted. The graph shows the load settlement curve. The ultimate bearing capacity is taken as the load at which the plate starts sinking at a rapid rate, i.e. when the curve drops down to a vertical line.

For further information on Plate Bearing Test Reports please click here

Geotechnical Resources

Here we have some of the examples of reports to help you understand what the different documents cover.

Geotechnical Resources

Report Examples

Example of Coal Mining Risk Assessment CMRA

Coal Mining Risk Assessments identify site specific coal mining risks and set out the proposed mitigation strategy to show that the site can be made safe and stable for the proposed development.

Example of Phase 1 Desk Study Report

Example of Plate Bearing Test (or Plate Loading Test)

The Plate Bearing Test (or Plate Loading Test) is an in-situ field test used to determine the ultimate bearing capacity of rocks and soils and anticipated settlement beneath an imposed load.

Click here for example of Plate Bearing Test (or Plate Loading Test)

For more information on Plate Bearing Test (or Plate Loading Test) examples please click here

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