Experimental Study On Rheological Behaviours Of Remolded Saturated Clay

Saturated clay exists widely in China's inland and coastal areas.Practice has shown that buildings(structures)based on saturated clay will have a large settlement after the completion of the project,and may even cause damage to the superstructure.This is because the cohesive soil has obvious rheological phenomenon under the long-term load.Therefore,in-depth study of the rheological properties of cohesive soils has important practical guiding significance for the post-construction settlement problems that occur in engineering.Based on the current research status of clay rheological properties at home and abroad,a series of laboratory rheological properties tests were performed on reshaped saturated clay in Henan,including one-dimensional flow with an improved WG high-pressure.The isotropic consolidation test and triaxial shear creep test performed by the GDS stress path triaxial apparatus,and the rheological properties of the test were analyzed,and the following conclusions were obtained:(1)One-dimensional rheological consolidation tests show that the loading ratio affects the axial deformation characteristics of the soil.With the increase of the vertical load,the secondary consolidation coefficient of the soil tends to increase first and then decrease.Under the same vertical load,the larger the loading ratio,the larger the secondary consolidation coefficient,and the larger the unloading ratio,the larger the rebound and secondary rebound coefficients of the sample after unloading.(2)Different grading loading methods will affect the final volume deformation of isotropic consolidation of the soil,and the final volume strain increases slightly with the increasing of grading times.Increasing the confining pressure will make the sample itself be more compacted,which will cause difficulty in draining the pore water inside the sample and prolong the pore pressure dissipation time.(3)For isotropic consolidation samples,the primary and secondary consolidation boundary time determined by the pore pressure dissipation method is always greater than the boundary time determined by the Casagrande method.This shows that there is a significant coupling effect in the primary and secondaryconsolidation.(4)The failure deviator stress of soil increases with the increase of confining pressure.The soil under low deviatoric stress exhibits the characteristics of attenuation creep,while under the action of higher deviatoric stress,the soil will undergo a stage of accelerated creep.The soils studied in this paper have nonlinear creep characteristics,and the greater the deflection stress,the more nonlinear the creep becomes.(5)The fractional five-element model can well describe the creep process of saturated clay under the action of partial stress,especially the accelerated creep situation,which is still applicable.