
Geotechnical Services

INDUSTRY LEADING
GBI is a team of geotechnical engineers, engineering geologists, technicians and health and safety officers.
We own and operate a modern fleet of field testing equipment. We can mobilise to sites on very short notice by managing most of our equipment and tools in-house.
HEALTH, SAFETY AND ENVIRONMENT
We don't take shortcuts when it comes to safety and quality.
We have a process in place to ensure staff are adequately trained on equipment, ensuring they work safely and provide quality results.
We have Safety Management Systems that cover client inductions, training, PPE, communication, vehicle safety, workplace safety, chemical safety and electrical safety. Our Staff are also experienced with working under both government and client requirements for Environmental and Heritage, including following protocols for protection of native vegetation, rubbish management, site clean-up, waste water management and clearing approvals. For example, diesel is used to power all generators to limit fire risk. Refuelling is undertaken over containment bunds with spill kits on hand. Our work procedures include, but are not limited to, daily prestart checks, job safety analysis, and safe work procedures.
Our staff, as a minimum, have completed the following courses:
• Whitecard (construction card) • Senior First Aid and • 4WD Driver Training.
Our employees also regularly complete mining company site clearances (including drug and alcohol clearances) and site inductions.

CPT Tracked Rig
The Pagani TG73-200 Cone Penetrometer Test (CPT) rig can typically test to depths of about 30m, depending on conditions. On site, this machine moves on rubber tracks and uses two augers to anchor it, allowing for a pushing force of up to 200kN. Cone penetration testing (CPT) is typically done in accordance with AS1289.6.5.1. The test involves pushing an instrumented cone into the soil with a hydraulically operated pushing frame. The test measures tip resistance and sleeve friction on the cone, which are then plotted with depth. Pore pressure in kPa can also be measured.

CPT Truck Rig
Iveco Trakker 6x6 truck
22.5 tonnes weight with 180 kN pushing force.
Cone penetration testing (CPT) is typically done in accordance with AS1289.6.5.1. The test involves pushing an instrumented cone into the soil with a hydraulically operated pushing frame. The test measures tip resistance and sleeve friction on the cone, which are then plotted with depth. Pore pressure in kPa can also be measured.

Dynamic Probe Super Heavy (DPSH)
GBI is one of only a handful of contractors in Australia who can offer DPSH testing.
The Dynamic Probe Super Heavy (DPSH) is a relatively small machine with rubber tracks, making it accessible in most locations.
The DPSH test involves driving a solid cone (20 cm2) into the ground using a 63.5kg hammer falling 760mm. Testing is done in accordance with EN ISO 22476-2 – Geotechnical engineering – Field testing Part 2: Dynamic probing – DPSH-B. This is essentially a continuous SPT. This test type is uniquely useful for profiling soil over rock and in desiccated, cemented and mixed soils that cannot be penetrated by CPT.
Results may be presented as either:
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Depth per blow (mm/blow);
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N10 (No. of blows required for every 100mm penetration);
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N30 (No. of blows required for every 300 mm penetration – this is approximately equivalent to SPT-N); or
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qd (dynamic tip resistance, analogous to CPT qc).

Diamond / Rotary Core Drilling
Diamond coring (or rotary coring) drilling is used for the recovery of a wide range of material, including cemented soil and rock. The machine is capable of drilling in all strengths of rock. Standard Penetration Tests (SPT’s) can be carried out, typically every 1.5m in soil layers. SPT’s are done in accordance with AS1289.6.3.1.
GBI offers drilling services with a trained drilling team, supplying all consumables and core trays, and can allow for water, if this is not available on site. Our head driller will provide you with a drillers log, summarising samples taken, SPT results, core loss, or any anomalies encountered during drilling.
The drillers log is not a formal log. We can offer a formal log, logged by a geotechnical engineer or technician in accordance with AS1726, if required.
Additionally, we can install monitoring wells and measure short-term or long-term water levels, and conduct infiltration tests. We can also sample water and rock/soil samples at your request.

Test Pits
We can carry out test pits and pavement dippings using either our own JCB 2CX, or hire larger plant (such as tracked excavators) should that be required.
GBI safely manages test pitting by ensuring barricading is in place and that no test pit is left open unattended.
If required, we can log test pits and sample soil and rock as required.

Vacuum Excavation
Working next to sensitive utilities like power and gas can be very dangerous, and sometimes it is mandated that services be exposed by means of vacuum excavation, prior to permission for other kinds of excavation being allowed.
GBI operates a compact vacuum excavation trailer, suitable for most sites.

Machine Auger Drilling
GBI operates 3 machine auger drilling rigs, capable of accessing most sites, including sand sites. Our auger rigs are mounted on 4x4 trucks and utes.
100mm diameter solid auger or 100mm (ID) hollow auger and can drill to 12m or shallower refusal. Wider diameter augers are also available.
The machine auger is suitable and useful in the following areas:
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Where drive-on access is available.
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Where limited ground disturbance is required (opposed to test pitting).
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Where several test locations are targeted. In ideal conditions, we can complete about 10 - 15 boreholes to a depth of 3 m in one day.
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In sandy and silty material.
GBI auger rigs can drill through asphalt (carparks and roads), but not concrete (we can pre-drill / core through concrete).
GBI auger rigs are particularly useful when combined with the Grizzly DPSH rigs and cross-trained operators can use both plant items on site on the same day

Locating Underground Services
True to our goal to be a one-stop shop for all your geotechnical needs, we can carry out locating of services using Ground Penetrating Radar, Locating Wands, and Concrete Scanners. This allows us to not only work safer, but also provide better value for our clients.

Infiltration Testing and Water Level Monitoring
GBI can assist with infiltration testing, using various methods, as well as short term and long term water level monitoring.
Infiltration Testing Includes:
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Inverse Auger Hole Method
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Double Ring Infiltrometer
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Guelph Permeameter
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Logging to AS 1726
We have a dedicated team of staff that is trained to log according to AS 1726.



