LABORATORY TEST AND NUMERICAL SIMULATION OF DEFORMATION CHARACTER FOR SOFT CLAY IN UNLOADING CONDITION

The displacement-time relationship curves are got from laboratory tests for the deformation character analysis of the soft clay in unloading condition.The stress control triaxial compression apparatus is used and remade from the strain control compression apparatus.The following conclusions are gained from the analysis of the test results: (1)when the amount of the loading and the unloading are the same,the amount of the deformation produced in the unloading process is much smaller than the amount of the deformation produced in the loading process.The former is just about one tenth of the latter; (2)the resilience is very small,when the portion of the unloading is small; (3)the resilience will increase sharply,when the amount of the unloading is big enough; (4)the resilience deformation will trends to be stable,when the portion of the unloading exceeds another point.The finite element analysis software ABAQUS is used to simulate the laboratory test.The displacement-time relationship curves are got from the numerical simulation analysis.They revealed the following results: (1)the deformation-time curve in the unloading process is similar to the deformation-time curve in the loading process,when the amounts of the loading and unloading are the same; (2)the numerical calculated deformation increments are a little bigger than the deformation increments got from the indoor test in the initial and last periods of the whole unloading process,but fits well in the middle periods; (3)in every level of the unloading process,the relationships between the deformation and time got from the numerical simulation fit well with that got from the test.