Dynamic responses of calcareous foundation reinforced by microbially induced calcite precipitation

The microbially induced calcite precipitation (MICP) is a green and ecofriendly technique to efficiently improve soil strength and mitigate liquefaction potential of soil. In this study, the temperature-controlled MICP method is used to reinforce the foundation model made with the calcareous sand from the South China Sea. A series of shaking table tests are performed to investigate the effects of biocementation level and soil depth on the dynamic stress-strain relationship, shear modulus, shear wave velocity and dynamic strength of the MICP-treated calcareous sand foundation. The test results show that the MICP can affect the dynamic response of the calcareous sand foundation significantly, indicating that with the increase of the biotreatment level, the dynamic shear strain decreases significantly; the area of stress-strain hysteresis ring and the energy dissipation decrease; the dynamic shear modulus increases with the decrease of increment amplitude; the shear modulus degradation at a larger depth is higher than that at a lower depth. The shear wave velocity increases with the biocementation level and becomes higher after shaking. The dynamic strength equation for the biotreated soil models from the triaxial cyclic loading tests, multiplying a reduction coefficient, can be used to simulate the dynamic soil strength of the MICP-treated calcareous sand foundation in the shaking table tests.