CPT - Cone Penetration Testing / Cone Penetration Test

The Cone Penetration Test (CPT) is an in situ method of testing used to determine the composition and geotechnical engineering properties of soils without taking a sample.

The CPT is one of the most used and accepted in situ test methods for soil investigation worldwide.

The CPT test method consists of pushing an instrumented cone, tip first into the ground at a controlled rate of 2 cm per second. Continuous measurements of the resistance to this penetration are recorded as qc (end resitance) and fs (sleeve resistance). Where pore pressure is measured the test is referred to as CPTU.

Very early methods of soil probing existed but this form of CPT can be traced back to the 1930s in the Netherlands and hence CPT has also been referred to as the Dutch Cone test.

Datem Ltd manufactures CPT equipment for sub-sea use. Our two most commonly used systems world-wide are from the Neptune range, Neptune 3000 and Neptune 5000.

The Neptune 3000 is compatible with 2cm2 and 5cm2 cones. It is a light-weight coiled rod CPT system which allows for the thrusting of an instrumented geotechnical cone up to 10 meters in penetration. The unit can be sub-merged up to 3000metres and is suitable for smaller vessels due to the compact, light-weight and easily deployed sub-sea frame. The Neptune 3000 CPT system can push up to a maximum of 1000kg (50Mpa with a 2cm2 cone).

The Neptune 5000 is compatible with 5cm2 and 10cm2. It is Datem’s heavy duty coiled rod CPT system which allows for the thrusting of a digitally instrumented geotechnical cone up to 20m in penetration. Like the Neptune 3000 the unit can be submerged in 3000 meters of water and features an easily deployed sub-sea frame. The Neptune 5000 CPT system can push up to a maximum of 3500kg (70Mpa with a 5cm2 cone).

The Neptune range of CPT systems push at a rate of 2cm per second with soil data recorded and presented in real time every 1mm of travel, giving instant on site results. They are low maintenance with low consumable use and feature automatic safety cut-outs. The CPT systems are controlled by Microsoft Windows compatible Control and Data Acquisition Software packages with the choice of either Serial or Ethernet communication.
 

The Result of a Neptune 5000 CPT (Cone Penetration Test, Values displayed in MPa)

Datem's Neptune 5000 CPT system in shallow water deployment