• We undertake geotechnical site investigation in accordance with AS 1726.
• Both intrusive and non-intrusive ground investigation for assessment of prevailing subsurface conditions.
• Example techniques we apply in site investigation: Test Pit excavation, Borehole drilling with SPT testing and U Tube undisturbed sampling, Hand Auger Hole drilling, Cone Penetrometer Testing (CPT) with or without Piezocone, Perth Sand Penetrometer testing (PSP), Dynamic Cone Penetrometer testing (DCP), Field Permeability or Infiltration Test, Geophysical Survey (MASW and GPR).
• Soil and rock profile engineering logging, classification and visual inspection.
• Report writing – factual and interpretive.
• Design input – we infer/estimate geotechnical design parameters for structures / foundations; earthquake parameters, site sub-class and liquefaction potential; groundwater and soils aggressivity exposure classification to buried concrete and steel elements; permeability/infiltration rate; horizontal and vertical subgrade reaction / spring constant.
• Site class assessment for residential and commercial developments in accordance with AS 2870.
• Estimate bearing capacity / load bearing capacity and corresponding settlement.
• Stormwater disposal suitability assessment for a site.
• Pavement dipping for assessing the existing and proposed base, sub-base and subgrade conditions.

Generally, we undertake a desktop study combined with a site walkover and minimal intrusive investigation for the assessment of its existing conditions. This preliminary level geotechnical and environmental study is an inexpensive way of identifying important information / potential issues on a site you are considering purchasing or developing.

The due‐diligence study supplements the work to be undertaken at the detailed investigation stage.

Example techniques we design and implement based on project’s merits: deep densification, preloading/ surcharging, prefabricated vertical drains/vertical strip drains/ wick drains, stone columns, controlled modulus columns (CMC), lime and cement stabilisation.

We model the site and ground improvement scenarios based on site investigation data and estimate various stage parameters, strength and stiffness, settlement and duration.

For most granular soil (sand, gravel, and gravelly sand) the groundwater table during construction should be maintained at least 1 m below the slopes and bottom of an excavation in order to ensure ‘dry working conditions’. It may need to be maintained lower depths for cohesive soils (clay, silts, around 2 to 3 m below bottom of excavation).

We consider the following groundwater control methods:

1. Interception and removal of groundwater from the site by pumping from sumps, wells, wellpoints, or drains.
2. Reduction of artesian pressure beneath the bottom of an excavation.
3. Isolation of the excavation from the inflow of groundwater by a sheet pile cut off, grout curtain, slurry cut off wall.

After understanding the requirements for groundwater control, we select preferred method, estimate total flowrate, assess total time for target drawdown, assess the settlement risk and then undertake detailed dewatering system design and management plan.

We support onsite dewatering plan implementation and monitoring.

• Due diligence study
• Site investigation
• Site class (as per AS 2870) and site sub-soil class (as per AS 1170.4)
• Materials search
• Fill material assessment and landfill material classification
• Ground improvement and monitoring
• Earthworks design and supervision support (as per AS 3798)
• Upgraded site class assessment
• Performance assessment of a swale or a water storage sump
• Report preparation for planning and approval purpose
• Construction support

• Due diligence study
• Current and historic land use study
• Environmental site investigation / assessment
• Acid Sulfate Soils (ASS) Management Plan
• Dewatering Management Plan
• Contaminated and ASS site classification category in accordance with contaminated site Act 2003 WA and DER criteria.
• Assessment of risk to health and to the environment.