Abstract: This paper presents the laboratory test results of the dynamic response of soft clay samples under dynamic load and undrained conditions by the improved static and dynamic true triaxial test system SPAX2000. The typical soft clay samples (moisture contents between 50% and 68%) were under various cell confining pressures (100 kPa, 150kPa and 200 kPa) and tested with different loading frequencies (1 Hz, 5 Hz and 10 Hz). The following conclusions can be obtained: within the shock loading consolidation stage, under the same cell confining pressure and different loading frequencies, the peak value of the deviator stress and the axial strain decrease with the increase of loading frequency; under the same loading frequency and different cell confining pressures, the peak value of deviator stress increases with the cell confining pressure; and the axial strain decreases with the cell confining pressure. The relationship between the rate of the deformation modulus increase and the number of dynamic loading are established from the test results. The application range of this empirical relationship is also provided in the paper.

Key words: Soft Slay;Triaxial Test;Loading Frequency, Confining Pressure, Deformation Modulus