Posted by / 08-Feb-2017 09:00


This research consists of a systematic review of the methods available to estimate preconsolidation pressure and sample quality.It focuses on multiple disturbance-simulation triaxial tests on resedimented San Francisco Bay Mud (RSFBM) specimens.After every disturbance simulation circle, the specimens are reconsolidated using SHANSEP technique, well into the Virgin Compression Line (VCL), to erase all the previous effects of disturbance.Then, every recompression curve is treated as an initial compression phase but, of known disturbance.Results also indicate that the effects of disturbance are much less apparent when the OCR increases and that accounting for swelling leads to an overestimation of the preconsolidation pressure.A new method called the “log-log method” has been proposed for a more accurate determination of preconsolidation pressure.

The results given by the log-log method were then compared with those given by conventional Casagrande method, and it was found that the new method gave values closer to the chosen sustained pressures, assumed as the real pc values for the purpose of comparison.

However, in practice, few qualitative methods are used even in the most complex engineering projects.

Furthermore, there is not a widely accepted, quantitative method in order to assess sample disturbance and treat the lab engineering values to match the "in-situ" properties of the soil.

The apparatus, called the Warren Spring-Bradford cohesion tester, works according to the principle of the annular shear cell.

Also, chopped corn stover exhibited the highest angle of internal friction, unconfined yield strength, major consolidation strength, and cohesive strength, all of which indicated increased challenges in handling chopped corn stover.