Load velocity influence on changes of soil consolidation and permeability parameters in CL-type tests

Obtaining the reliable values of filtration – consolidation parameters depends on appropriate programming of load velocity. In the paper a critical assessment of the criteria for selecting the load velocity with regard to theoretical model of consolidation under constant rate of load (CRL) was presented. A key element of interpretation is to distinguish three stages of investigation: mobilization of pore pressure, steady phase and unsteady phase. Reliable values of filtration – consolidation parameters are obtained during steady phase, determined on the basis of dimensionless, standardized for CRL tests parameters: the pore pressure and relative time of consolidation CL (continuous loading). In order to assess trends in changes of filtration – consolidation properties of Krakowiec formation clays were chosen for investigations. The tests were performed on undisturbed samples and using soil pastes at different load velocities to propose method to choose appropriate test speed in CL tests.