Experimental Study On Time-dependent Deformation Of Saturated Silty Clay

Time-dependent is a significant characteristic of soft soil deformation, what causes this phenomenon can be attributed to the soft soil in various environment with the characteristics of consolidation and physical properties. Because the time-dependent of soft soil deformation, settlement amount will gradually increase over time when the structure construction on soft soil foundation, leading to problems such as the structure stability of the structure, thus affect the normal use of structure, even result in structure damage, collapse and other serious accidents. Therefore, the use of indoor experimental research on the limitation of deformation of soft clay, discuss the rate effect of soft soil deformation and creep property, study the law of the deformation, it has great significance for forecast analysis of the soft soil foundation in practical engineering construction stability, safety and durability.In order to explore the deformation of saturated silty clay timeliness, basing on the mechanism of deformation of saturated soft clay under different conditions of indoor test scheme is designed, and analyzing the characteristics of the deformation rate of saturated silty clay and creep properties and the stress-strain characteristics. The main contents and conclusions of the research are as follows:A. The rate of saturated silty clay effect test and theory research:1. Triaxial consolidation undrained shear strain rate test of saturated silty clay under different axial strain rate and confining pressure.2. By describing the saturated silty clay rate curve can be found that the stress-strain curve show obvious hyperbolic form, the Kondner stress-strain hyperbolic model can fitting the experimental data very well.3. By comparing the same confining pressure, different rate under triaxial undrained shear test data such as strain rate, can be found that with the increase of shear rate, saturated silty clay in the shear strength increased significantly. And according to the existing research, analysis of saturated silty clay of the relationship between shear strength and shear strain rate;4. Combine Kondner stress-strain hyperbolic model and the shear strength-rate equation of saturated silty clay, puts forward the saturated silty clay in axial strain rate under the condition of stress and strain-rate equation, and determine the parameters in the model, compared with the test results verify the applicability of the model.B. The creep test of saturated silty clay and theoretical research1. The saturated silty clay of creep test under the condition of different confining pressure and stress level.2. By depicting the saturated silty clay creep test curve can be found that saturated silty clay has creep performance.And creep curve at a certain stress level within the scope of the law of development is consistent, in the initial stage, the creep curve is steeper, but the curve tends to be flat in the creep stage; When the same confining pressure, with the increase of stress level, the creep variable increases.3. The error of creep equation and test data is large by using Singh-Mitchell creep model fitting under different confining pressures of saturated silty clay. The hyperbolic creep equation has high accuracy, but it is short of theoretical significance.4. Combining the advantages of Singh Mitchell model and hyperbolic model, the modified Singh-Mitchell creep equation not only expressed in simple, clear physical meaning, but also accurately reflect and predict the creep properties of saturated silty clay in different confining pressure, and different stress level conditions.The saturated silty clay is deformed after loading, as time changes and strain is also changing, that is to say, the saturated silty clay has the characteristic of deformation time-dependent. Through from two aspects of rate effect and creep effect study of deformation of saturated silty clay timeliness, working out the uniform stress and strain-rate equation and modified Singh-Mitchell creep equation, which is able to accurately describe rate effect test and creep test in this paper.