As shown in Fig. 4, the most unique feature of the apparatus
is that two parallel specimens of the same soil are tested simultaneously,
instead of just one. Such a special configuration,
in conjunction with very stiff components of the device and
the high-precision noncontact displacement transducers, enables
almost complete elimination of problems associated with
false deformations, system compliance, and friction. As a result,
very small strains and stresses can be applied and measured
in a controlled manner. Typical records of a test on Clay
A are presented in Fig. 5.
In Fig. 6, four loops obtained for Clay B at four different
levels of 'Ye are presented. The figure illustrates the smallest
'Ye for which the cyclic stress-strain curve, and thus the area
aW and A, can be accurately measured in the DSDSS device.
It can be seen that for the largest 'Ye .... 0.011% [Fig. 6(d»), the
shape of the loop is well defined and aW can be determined
precisely. For the smallest 'Ye .... 0.002% [Fig. 6(a»), the shape
of the loop is less well defined, but aW can still be determined
approximately. This indicates that the smallest 'Ye for which A
can be measured in the DSDSS device with an acceptable
accuracy is around 0.002%
As shown in Fig. 4, the most unique feature of the apparatusis that two parallel specimens of the same soil are tested simultaneously,instead of just one. Such a special configuration,in conjunction with very stiff components of the device andthe high-precision noncontact displacement transducers, enablesalmost complete elimination of problems associated withfalse deformations, system compliance, and friction. As a result,very small strains and stresses can be applied and measuredin a controlled manner. Typical records of a test on ClayA are presented in Fig. 5.In Fig. 6, four loops obtained for Clay B at four differentlevels of 'Ye are presented. The figure illustrates the smallest'Ye for which the cyclic stress-strain curve, and thus the areaaW and A, can be accurately measured in the DSDSS device.It can be seen that for the largest 'Ye .... 0.011% [Fig. 6(d»), theshape of the loop is well defined and aW can be determinedprecisely. For the smallest 'Ye .... 0.002% [Fig. 6(a»), the shapeof the loop is less well defined, but aW can still be determinedapproximately. This indicates that the smallest 'Ye for which Acan be measured in the DSDSS device with an acceptableaccuracy is around 0.002%
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