Hand vane shear strength vs hand penetrometer
Hand vane shear strength vs hand penetrometer
(OP)
Is there any way of converting the results from a hand penetrometer into Cv
Thanks in advance
Regards
andy
Thanks in advance
Regards
andy





RE: Hand vane shear strength vs hand penetrometer
Not sure if the question relates to the title of your query. The hand penetrometer is a device to measure the cohesive shear stength of a soil Cu. This is done directly and your penetrometer should come with a calibration sheet so you can convert the penetrometer reading directly into a cohesive strength. A hand shear vane will also give an instant Cu reading from the calibrated dial on top of the rotating head. If you are asking for a measurement of Cv (coefficient of volume compressibility) then I'm afraid you need to perform an oedometer test in the lab. There is no way I know of of obtaining Cv from a penetrometer as Cv requires accurate measurement of volume change which a penetrometer clearly cannot provide.
Best regards
Ginger
RE: Hand vane shear strength vs hand penetrometer
RE: Hand vane shear strength vs hand penetrometer
A hand pentrometer purports to measure unconfined compressive strength (referred to as Qu typically). Vane measurements yield undrained shear strengths (referered to as Su or Cu typically).
Unconfined compressive strength is one half of undrained shear strength.
I have used the hand penetrometer frequently in both normally consolidated clays and in heavily over consolidated tills. The vane is the preferred field instrument, however the large amount of stone in the tills makes it necessary to use other means. I have found that the penetrometer shows reasonably close agreement to the results of unconfined compressive testing.
I have not subjected this to any statistical analysis, but think I am accurate in stating that the penetrometer results agree, within 25% to 50%, to the results of Qu testing, when performed on tills.
Having said all this, however, I would not think of the results as anything more than a strength index, and would not stretch the results to the extreme of using them for consolidation or compressibility parameters.
RE: Hand vane shear strength vs hand penetrometer
RE: Hand vane shear strength vs hand penetrometer
Regards
Andy Machon
RE: Hand vane shear strength vs hand penetrometer
In your case, 73 kPa is about 0.75 tsf, or 1500 psf, or a little more than 10 psi.
RE: Hand vane shear strength vs hand penetrometer
RE: Hand vane shear strength vs hand penetrometer
The friction angle parameter (phi) is fundamental in ascertaining the bearing capacity of the ground. Whichever method you use (Prandtl, Reissener, Terzaghi etc), they all rely on a function of phi. When phi increases, so does the bearing capacity of your foundation.
Regards
Andy Machon