Experimental research of the effects of preconsolidation on the time-dependent deformations-creep of marl

Experimental research on marl prismatic specimens under uniaxial loading indicated that, under the constant uniaxial compressive stress, marl exhibits significant time-dependent deformations, creep. A rheological model for soft rock is defined for creep after the loading and unloading (Tomanovic in Mech. Time-Depend. Mater. 10(2):135-154, 2006), whereas material parameters for the rock concerned are determined based on the result of the creep test after the initial loading. The influence of the compressive stress preconsolidation level and the loading duration on material parameters that describe the creep represents the central part of this examination. For the purpose of quantification of material parameters of the rheological model that describes creep, the laboratory research has been resumed using series of prismatic specimens under uniaxial load. The paper presents some of the so far registered results of the marl creep behavior, following previously conducted creep tests at different stress levels and different loading duration.