Protocol for Site Investigation
This page describes the protocol adopted for the conduct of site investigations carried out by Michael D Joyce Associates LLP.
The main objective of any investigation is to provide sufficient information for the safe and economic development of a site at minimum cost. Clearly no guarantee can be given that all relevant conditions will be identified but the work carried out will be aimed at reducing risk to acceptable levels.
Increasing expenditure on site investigation will always reduce the risk of unforeseen conditions but professional judgment and experience will be exercised as to that work which is considered necessary in the best interests of the client.
Not all facets of the work will be needed on any individual investigation but consideration will be given in all cases to their relevance and application. Work will be carried out in accordance with the Code of Conduct published by the Association of Geotechnical and Geoenvironmental Specialists (available on request) and in accordance with relevant Health and Safety and CDM legislation.
Codes of practice and guidance
Work will be carried out in accordance with recommendations made in the following documents:
- BS5930 Code of Practice for Site Investigations
- BS8002 Earth Retaining Structures
- BS8004 Foundations
- BS8006 Strengthened/Reinforced Soils
- BS1377 Testing of Soils for Civil Engineering Purposes
- NHBC Standards - Chapter 4
- Site Investigation Practice by Michael D Joyce, E & FN Spon 1982
- Safety Manual for Investigation by the Association of Geotechnical and Geoenvironmental Specialists
- Site Investigation and the Law by Cottington & Akenhead 1984
- Site Investigation in Construction - 4 volumes by the Site Investigation Steering Group
Staff
All work carried out by this practice will be by a Chartered Engineer or Chartered Geologist with 16 years minimum relevant experience and who is qualified as a Geotechnical Specialist or a Geotechnical Adviser as defined by the Site Investigation Steering Group.
Desk study
- Geology, hydrogeology, hydrology
- Flood risk assessments
- Archival mapping and historical land use
- Mining and landfill identification
- Radon risk assessment
- Munitions and unexploded ordnance
- Environmental constraints
- Conceptual site models
- Geoenvironmental and geotechnical risk assessment
Trial pitting
Trial pits will be dug by excavator to the maximum depth possible, unless precluded by the ground conditions. Trial pits will be described and logged to BS5930 by a Chartered Engineer/Geologist. Samples will be taken for laboratory testing as appropriate. In-situ vane shear strength and CBR testing will be carried out.
In-situ gas testing for methane, carbon dioxide and oxygen will be carried out and, where necessary, monitoring pipes installed. Trial pits will be reinstated using the arisings unless a higher standard of reinstatement is specified.
Boreholes
Boreholes will be drilled wherever necessary to identify soft or made ground, the site geology, shallow mineworkings and shafts in accordance with BS5930 and the 'Specification for Ground Investigation' published by the Site Investigation Steering Group.
Fieldwork will be supervised by a Chartered Engineer/Geologist.
Boreholes will be reinstated using the arisings unless otherwise specified.
Instrumentation and geophysics
Where appropriate and cost effective instrumentation can be istalled and geophysical surveying carried out.
Laboratory testing
Samples taken for laboratory testing will be tested by a NAMAS accredited laboratory for the following as appropriate.
Moisture content, grading, plasticity and classification, shear strength, CBR, sulphate and acidity.
Permeability, compaction and consolidation characteristics.
Chemical testing to assess contamination and potential effects on structures by UKAS accredited laboratories.
Reporting
Reports will include a site location plan and plan showing any special features plus borehole and trial pit locations. Factual reports will describe the work carried out and will include borehole/trial pit logs and the results of all in-situ and laboratory testing.
Interpretative reports will include recommendations as appropriate to the following:
- Foundations
- Strip, raft or piled
- Depth, bearing capacity and settlement
- Pile depths and loadings
- Interaction with existing features
- Effects of groundwater
- Protection against chemical attack
- Design criteria for retaining structures
- Earthworks
- Stability and interaction with existing features
- Re-use of excavated materials
- Consolidation and settlement
- Groundwater control and heave
- Construction methods
- Types of fill and their compaction
- Slope stability and remedial works
- Effects of quarrying and made ground
- Ground improvement
- Consideration of the use of ground improvement techniques and geotextiles
- Grouting and stabilisation of mineworkings and shafts
- Roadworks
- Strength and stability of subgrade
- Construction thicknesses
- Frost susceptibility
- Need for capping layers/geotextiles
- Excavations
- Stability and groundwater control
- Ease of excavation
- Control of groundwater
- Re-use of spoil
- Rock levels
- Environmental factors
- Identification and remediation of contaminated land
- Control of landfill or radon gas and leachates
- Need for monitoring
- Special factors
- Identification of "significant risk of significant harm" as defined by the Environment Act 1995
Where special features arise, appropriate recommendations will be given. Where existing information is considered inadequate and the risk of unforeseen conditions is high, recommendations will be given for additional work. Where appropriate, recommendations will be made for monitoring and instrumentation.