Test Research On Deformation Characters Of Consolidation And Creep For Soft Clay Under Different Drainage Conditions

The engineering problems such as the large settlement of the buildings (structures)on the soft clay foundations and the lach of bearing capacity of the foundations are usually generated by the high aquosity,high void ratio,high compressibility,low shear strength and obvious rheology property, so the consolidation and creep character research to the soft clay is a study that is pregnant both in theory and actual engineering.A sery of triaxial consolidation and creep test are adopted on the stress controled triaxial apparatus adapted from the strain controled triaxial apparatus. The consolidation and creep character of the typical soft clay in Wuhan in different drainage conditions and stress level are investigated; the influence of the drainage conditions on the consolidation and creep character are analyzed according to the comparation of the stress-time,strain-time relationship curve in different drainage conditions; and the consolidation and creep deformation pattern are got for the typical soft clay in Wuhan, the empirical equations in different stress level for the soft clay are presented by the data process software, which can be used as the logical ground to the actual engineering.The conclusions are got from the test result as below:The creep deformation amount increases with the increase of the stress level in the same drainage condition. When the stress level is low, the consolidation deformation is the main deformation, the creep is not so obvious that the creep is attenuation creep and the tends to be stable at last corresponded to the loading; when the stress level is high, the creep deformation is the main deformation and the deform rates at the instantaneous deformation period and the creep deformation period will increase and the whole deformation amount will increase too, which is called the non-attenuation creep. The drainage condition is very important to the consolidation and creep character of the soft clay. When the stress level is low, the deformation amount in the undrained condition is much smaller than that in the drained condition. When the stress level increases, the visco-plasticity character of the soil will display, and the deform rate will surpass that in the drained condition, and when the stress level is high enough, the deformation amount in the undrained condition will surpass that in the drained condition.The empirical equations of the consolidation and creep deformation for the typical soft clay in Wuhan in different drainage conditions are fitted by the data precess software with generalized Kelvin Model, and the results from compraration analysis demonstrates that the generalized Kelvin Model can well illustrates the consolidation and creep deformation pattern for the typical soft clay in Wuhan.