16 Q2.2 Solution Typical graphs of (a) shear stress τ against shear strain γ ; (b) volumetric strain ε vol against shear strain γ ; and (c) specific volume v against shear strain are as shown in main text Figure 2.21. In the test carried out on the initially dense sample, the shear stress gradually increases with shear strain to a peak at P, before falling to a steady value at C which is maintained as the shear strain is increased. The sample may undergo a very small compression at the start of shear, but then begins to dilate. The curve of ε vol vs becomes steeper, indicating that the rate of dilation -d vol /d is increasing. The slope of the curve reaches a maximum at p, but with continued shear strain the curve becomes less steep until at c it is horizontal. When the curve is horizontal d vol /d is zero, indicating that dilation has ceased. The peak shear stress at P coincides with the maximum rate of dilation at p. The steady state shear stress at C corresponds to the achievement of the critical specific volume at c. The initially loose sample displays no peak strength, but eventually reaches the same critical
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This note was uploaded on 12/28/2011 for the course CHM 4302 taught by Professor Stuartchalk during the Fall '11 term at UNF.