| Type |
Brief Description (and client role) |
Typical Application |
Methods Typically
Employed by IGS Operator |
| IGS-1 |
Standard Piezocone Testing
Client must (pre-testing) brief IGS on their choice of this type. Little or no client involvement is required during testing progress.
Objective is good quality data, including good pore pressure response. However, if pore pressure response problems evolve in any “difficult” test zone, time is not squandered trying to solve them.
Typically a client is hoping for reasonably high productivity using this method. |
For use when clients want a reliable soil profile and to establish design parameters to historically-normal levels of client expectation.
May be the base test type chosen for a known soft clayey soil project for overall site profiling.
Good quality pore pressure response is usually achieved |
Usually 100MPa, 10cm2 compression cone is used.
Cone is carefully prepped and pore pressure measurements are made as test progresses.
If soil behaviour spoils piezo response in some zones, test penetration is paused briefly to permit “catch up”.
Should difficult soil layers be encountered (eg gravely bands or hard fissured layers causing tilt), test may need to be immediately discontinued – at discretion of IGS operator. |
| IGS-2 |
Subtraction Piezo-Cone Testing
Client must (pre-testing) brief IGS on their choice of this test type. Little or no client involvement is required during testing progress.
Objective is good quality data, including good pore pressure response. However, if pore pressure response problems evolve in any “difficult” test zone, time is not squandered trying to solve them.
Typically a client is hoping for high productivity using this method, even in some difficult-to penetrate soils (eg bands of dense sands, hard fissured clays, etc) |
For use when clients want a reliable soil profile and to establish design parameters at “site characterisation” level.
May be the base test type chosen for a variable or unknown soil type for overall site profiling.
Good quality pore pressure response is usually achieved and “normal” dissipation tests can be made. |
Usually 100MPa, 15cm2 subtraction cone is used.
Cone is carefully prepped and pore pressure measurements are made as test progresses.
If soil behaviour spoils piezo response in some zones, test penetration is continued.
Should difficult soil layers be encountered (eg gravely bands or hard fissured layers causing tilt), test can typically be carefully continued – at discretion of IGS operator. |
| IGS-3 |
Subtraction Non-Piezo-Cone Testing
Client must (pre-testing) brief IGS on their choice of this type. Little or no client involvement is required during testing progress.
As cone does not have a piezo-element, cone preparation is much simpler and quicker – leads to higher project productivity.
Can be used even in some difficult-to-penetrate soils (eg dense sands, hard fissured clays, etc). |
For use when clients want a reliable soil profile and to establish design parameters at “site characterisation” level. But pore pressure response is not required.
May be the base test type chosen for a variable or unknown soil type for overall site profiling. IGS recommends this if budget control is critical and site characterisation is the objective. |
Usually 100MPa, 15cm2 subtraction cone is used.
Should difficult soil layers be encountered (eg gravely bands or hard fissured layers causing tilt), test can typically be carefully continued – at discretion of IGS operator. |
| Type |
Brief Description (and client role) |
Typical Application |
Methods Typically
Employed by IGS Operator |
| IGS-S |
Special-Class Testing.
Client must advise IGS of their expectations, as test productivity may sometimes be reduced using this method.
Objective is best possible pore pressure response in “difficult” ground, but still maintaining reasonably high productivity.
Client might intervene during progress to shift test type to IGS-R, accepting lower test productivity that results in this shift. |
Typically used at targeted locations after site characterisation by IGS-1, IGS-2 or IGS-3 testing.
Client wishes to obtain inputs into determination of soil parameters to a “specially” high level.
Typical objectives may be assessment of soil properties for design of embankments or preloads over soft to firm and stiffer clay-type foundation soils. Dissipation tests should be achieved to a high standard. |
Cone capacity is selected to suit the ground being targeted (eg 100MPa or 10MPa cone choice is made). 10cm2 compression cone is used.
Pore pressure measurements are closely watched as test progresses. If soil behaviour spoils piezo response in any zones, test penetration is stopped while response monitoring continues.
If piezo “recovers” in (say) 10-15 minutes test penetration is restarted. If piezo does not “recover” in (say) 10-15 minutes, test penetration might also be started but client accepts consequences of possible zones of reduced pore pressure response. (Note that client can up-grade to IGS-R if desired). |
| IGS-R |
Quasi-Research Class Testing.
Client must be closely engaged in decision process as in extreme conditions test productivity may be quite low using this method.
Objective is best possible pore pressure response in “difficult” ground, more-or-less regardless of productivity. |
Typically used at targeted locations after site characterisation by IGS-1, IGS-2 or IGS-3 testing.
Client wishes to obtain inputs into determination of soil parameters to the highest practically achievable level.
Typical objectives may be assessment of preconsolidation pressure of very soft clays, or assessment of preload progress based on qc or qt parameters. Dissipation tests should be achieved to best possible standard. |
Cone capacity is selected to suit the ground being targeted (eg 100MPa or 10MPa cone choice is made). 10cm2 compression cone is used.
Pore pressure measurements are closely watched as test progresses. If soil behaviour spoils piezo response in any zones, test penetration is stopped while response monitoring continues.
If piezo “recovers”, test penetration is re-started. If piezo does not “recover”, cone may be pulled out, hole may be water-filled and test may be recommenced with a re-prepped cone. |
