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Rod friction on vane shear test measurements Back to Forums

Asked by Azaiez Dalel Feb 7, 2017 07:53 Answers (3)

hello,

Would you tell me please how to caluclate the undrained cohesion from in-situ vane shear test when there is a registration of rod friction? and is there any documents , publications or refrences obout this issue?

Thanks for your help.

 

3 Answers

    ASTM D2573 on the Vane Shear Test shows the methods.  For rod friction you should use a vane with a slip coupling, or you can use some blank rods tests.  ASTM.org and costs $30.  I have some other publications if you like...I hlped write the ASTM revisions.  Most equipment has the slip couplings and thin low area ratio blades today.

    Thank you very much ; indeed having some references and publications will help me a lot .Would you tell me please about the variation of the rod friction when rotating the vane; does it rise whith the angle of rotation measured or it is constant ?

    I think it's considered a constant.  The friction couplers allow the rods above the vane to spin 15 degrees before the vane is engaged.  That friction is subtracted from the peak and remolded readings.vane

    go to roctest.com and look up the M1000 vane borer...a good mechanical vane.