Geotechnical investigations and reports
When planning your next development, it’s important to make sure that ground conditions are suitable to build on. Slope stability issues, fill and clay concerns, or piling requirements all need to be considered (and sometimes mitigated) before construction can start. That’s where a geotechnical engineer comes in.
With the right tools and experience, an engineer can identify potential problems before you design your foundation and structure. They’ll assess the ground at your planned build site and write a geotechnical report that identifies any potential issues and recommends a course of action.
STA Consulting Engineers are one of Australia’s leading specialists in geotechnical engineering for residential and multi-storey structures. Our geotechnical services include geotechnical investigations, slope stability analysis, and geotechnical reports. And with our own NATA accredited laboratory for thorough testing and analysis, you’ll get accurate reports and recommendations sooner so you can get on with the build.
Our geotechnical engineering process
Site assessment and database check
Report and QA review
Reports and certification issued
Why choose us?
Why choose STA for geotechnical engineering?
Experts in local geology
Site-specific foundation design
Analysis in our own NATA lab
Regional soil profile maps
Roger Connell // Managing Director
Get started with a geotechnical engineer
Tell me more about geotechnical engineering
What is geotechnical engineering?
Geotechnical engineering involves using science, tools, and techniques to understand the ground beneath a structure. Some geotechnical engineers (like STA) focus on how soil, rock, and groundwater could impact a building’s performance and design to minimise risk and maximise safety and longevity.
Geotechnical engineering informs the designs and materials for your building’s foundations, footings, and structure. It uncovers the level of earthworks and excavation needed, including temporary/permanent stability due to the excavation. It’s one of the first – and most critical – steps in a building project.
Why and when is it needed?
Geotechnical engineering minimises the risk that something could go wrong with your building because of the ground underneath it. When you know how the ground will affect your structure, you can make the right decisions from the start about where to build and what designs and materials to use.
Without a geotechnical investigation and report, you’re taking a significant risk that you’ll discover unexpected problems during (or even after) the build. This could massively bump up project costs if you need to adjust the design, change the location, redo the footings, purchase different materials, or repair damage.
Most of the time, it’ll make sense to get a geotechnical engineer in as early as possible – once you’ve secured the land and you know where you’d like to develop. Their reports will impact the build location, materials, and project costs, so the sooner you get them onsite, the better.
What's the soil bearing capacity standard in Australia?
Soil bearing capacity refers to the total building load a ground can handle without the soil over-settling or compressing.
The Building Code of Australia (BCA) requires a minimum bearing pressure of 100kPa for under strip and pad footing systems and 50kPa for under slab footings, as long as it’s a 1-2 storey building of typical construction methods outlined in the standards.
Some soils that are wet, sandy, or poorly compacted tend to have very low soil bearing pressure which makes them unsuitable for development. Your geotechnical engineer will test the ground to confirm suitability and include this information in your geotechnical or soil report report.
What's a geotechnical investigation?
A geotechnical engineer does “geotechnical investigations” where they visit the site marked for development, observe the soil, rock, and bedrock, and take samples for testing and analysis. On top of this, they’ll consider natural hazards like debris flows, rockfalls, landslides, sinkholes, and earthquakes. This is to understand what’s going on in the ground and how it may impact a building.
What's a geotechnical report?
After the geotechnical investigation is complete, your engineer will usually put their findings into a geotechnical report. This includes information on the site conditions, along with recommendations for the construction or design. The report is used during design and construction to guide decisions affecting the building’s foundation and structure, and it may be referred to post-completion to resolve claims.
Most geotechnical reports include:
- Subsurface soil profile
- Lab test results
- Groundwater info
- Subsurface soil profile
- Analysis of subsurface data
- Design recommendations
- Solutions for anticipated issues