Compression tests on a slurry using a small-scale consolidometer

To understand the deformation of ultrasoft soil in a viscous state, compression tests were carried out using a small-scale consolidometer equipped with pore-pressure transducers at three locations. Deformation behavior was monitored with both settlement and pore-pressure measurements. The transitional points from slurry to soil were determined from the settlement rate, change in void ratio, change in permeability, and pore-pressure dissipation. It was found that the transitional void ratio determined from the settlement rate is smaller than that determined from the commencement of pore-pressure dissipation. The transitional void ratio varied slightly for samples with different initial moisture contents determined based on pore-pressure considerations. The variation was due to the difference in sample thickness which affected the initiation of pore-pressure dissipation at the bottom of sample. In reality, the void ratio at transition could be larger than those determined from both settlement and pore pressure.