As part of TAILLIQ, we are using tube samples obtained adjacent to CPT probes to supplement and compare to our calibration chamber test results. Tube samples taken in saturated low plasticity tailings can, in some cases, provide a useful estimate of in situ void ratio by means of water content. The material recovered in the tubes can then be used to measure the CSL on reconstituted samples, and Ψ calculated in an manner completely independent from CPT-based methods.
As highlighted in the video, transport and handling densification within the tube can result in significant amounts free water being present above the sample, as observed during tube disassembly in the video. This suggests that attempting to test these kinds of tube samples in an “undisturbed” manner would provide unrealistic estimates of the contractive or dilative behaviour of the in situ material.