Abstract: The soft soil in Shantou area was improved by enzymeinduced carbonate precipitation method. The test of the medium principal stress ratio b value is carried out on improved soil samples by the true triaxial test instrument. Under the same confining pressure and different b values, the deviatoric stress and pore water pressure of the improved soil samples increase with the increase of b value. Both the middle principal strain and the small principal strain of the reinforced soil change linearly. With the increase of b value, the absolute value of medium principal strain and small principal strain also increases correspondingly. Under the same b value and different confining pressure, the deviatoric stress and pore water pressure of the reinforced soil increase with the rise of the confining pressure. The medium principal strain and small principal strain of the reinforced soil increase with the increase of the confining pressure, and the deformation amount increases accordingly. The experimental results provide theoretical basis and experimental support for soft soil engineering in Shantou area.

Key words: EICP, True Triaxial, Soft soil reinforcement