Experimental Study On Time-dependent Deformation Characteristics Of Reconstituted Saturated Silty Clay

Silty clay is widely distributed in coastal areas,and its time-dependent deformation will lead to ground settlement during and after construction.Therefore,a comprehensive understanding of the time-dependent deformation characteristics of silty clay has practical significance for the analysis of post-construction settlement of structures built in coastal areas.On the basis of previous research findings,laboratory tests,including one-dimensional oedometer test,isotropically compressed test and triaxial sheared creep test,were carried out on reconstituted saturated silty clay from Zhejiang coastal area.The time-dependent deformation characteristics of this reconstituted saturated silty clay under different load paths and with different load steps were tested.The main research contents of this paper are as follows:(1)The one-dimensional oedometer tests of reconstituted saturated silty clay were carried out with different vertical pressure steps,which studied the influence of different vertical pressure steps on its time-dependent deformation characteristics.According to the analysis of test data,the primary consolidation process and secondary consolidation process were isolated under one-dimensional condition.The logarithmic and hyperbolic creep models were used for fitting the experimental data,and it was found that the hyperbolic creep model was more suitable to describe this silty clay's time-dependent behavior.(2)The isotropically compressed tests of reconstituted saturated silty clay were carried on GDS triaxial apparatus to study the time-dependent deformation characteristics under different confining pressure steps.There were two methods to isolate the primary consolidation process and secondary consolidation process,namely “curve features method” and“pore pressure dissipation method”,and the secondary consolidation deformation was revealed accordingly.Finally the isotropically creepmodel was established for the secondary consolidation deformation which was obtained by two methods.(3)The triaxial sheared creep tests of reconstituted saturated silty clay were carried out with different deviator stress steps.Through the analysis of test data,the time-dependent deformation behavior under the condition of triaxial shear was obtained.After the primary consolidation process and secondary consolidation process were isolated,the triaxial shear creep model was established.