Before the engineer arrives
A successful site visit starts with confirmed access, current drawings, permission to enter and information about existing buildings, gates, landscaping, overhead restrictions and buried services. Investigation locations should relate to the proposed footprint or specific engineering question rather than being selected without reference to the development.
For restricted-access residential sites, photographs and measurements of side passages, steps and gates help identify appropriate equipment. Safe access and service clearance remain essential regardless of the chosen method.
Site walkover and observable ground conditions
The field team observes terrain, drainage, existing structures, vegetation, visible fill, retaining features, nearby slopes and signs of movement or seepage. These observations help interpret the subsurface results and may identify conditions requiring a modified scope.
A walkover cannot establish the complete ground profile by itself. Subsurface investigation is selected according to the agreed objectives, available access and practical site constraints.
Boreholes, augers, test pits and in-situ testing
Depending on the project, investigation may involve hand augers, compact or mechanical drilling, test pits, dynamic cone penetrometer testing and the collection of soil or rock samples. The selected combination should respond to the required depth, anticipated materials and engineering questions.
A dynamic cone penetrometer provides an indication of resistance in suitable materials; it is not a stand-alone substitute for every aspect of site classification or detailed geotechnical interpretation. Laboratory testing is selected where the results inform the assessment.
- Confirm investigation points, access and visible site conditions.
- Investigate the agreed locations using suitable field methods.
- Record observed fill, soil, weathered material and rock profiles.
- Note relevant seepage or groundwater encountered during fieldwork.
- Collect selected samples or in-situ observations where required by scope.
- Record limitations, refusal, access constraints and any unexpected conditions.
What field observations do and do not prove
An investigation records conditions at the locations accessible at the time. Soil or rock layers can vary between points, and groundwater observations can change with weather, drainage and season. Results must therefore be interpreted within the report's stated scope and limitations.
Unexpected fill, shallow rock, soft ground or restricted drilling may require the engineer to discuss revised scope before reliable recommendations can be completed.
Preparing your Sydney property
Provide the site address, building footprint, plans, utility information and access photographs before attendance. Tell the engineer about existing paving, pets, irrigation, septic systems, demolition, retaining walls, recent earthworks or any approval-related request.
Site disturbance and reinstatement expectations should be discussed before fieldwork. The practical arrangements depend on the chosen equipment, surface condition and investigation scope.
Common questions
What happens during fieldwork: common questions
Will every site need a drilling rig?+
No. Suitable methods depend on required depth, expected materials, site access and the design question. Some projects may use hand equipment, compact equipment, test pits or other appropriate methods.
Does a DCP test replace a complete geotechnical investigation?+
No. Dynamic cone penetrometer results are one potential source of field information and must be interpreted with the site conditions, investigation scope and other relevant observations.
Can fieldwork guarantee there are no unexpected ground conditions?+
No. Ground conditions can vary between investigation points and access limitations may restrict the available observations.
Need geotechnical site investigation in Sydney?
Get a scope matched to the project
Send the site address, proposed works, current plans and any request from your builder, engineer, council or certifier. Sydney Geotechnical will review the information and confirm an appropriate scope and fee.
This guide provides general information only and is not a substitute for investigation, engineering advice, footing design or approval advice for a particular property. Project requirements and ground conditions must be assessed site by site.
