微生物加固钙质砂动孔压模型研究

The calcareous sand foundation may be liquefied to cause structural damages under dynamic loadings such as earthquakes and waves. The microbially induced calcite precipitation(MICP) can enhance the strength of the calcareous sand foundation on a large scale and improve its liquefaction resistance. In this paper, the dynamic pore pressure development of MICP-treated calcareous sand was studied through a series of cyclic triaxial tests, and the effects of the effective confining pressure, the dynamic stress ratio, the relative density and the biocementation level on the development of the dynamic pore water pressure of MICP-treated calcareous sand were investigated. It is found that the pore water pressure development of MICP-treated calcareous sand is greatly affected by the dynamic stress ratio and the biocementation level. Based on the dynamic stress ratio and the biocementation level, MICP-treated calcareous sand presents three different pore water pressure development patterns. The pore water pressure curve gradually transitions from S-type to hyperbolic type with increasing the dynamic stress ratio or the biocementation level. Based on the development of the dynamic pore water pressure, an uniform pore water pressure model was proposed for MICP-treated calcareous sand. The advantage of this model over other models in predicting the development of the dynamic pore water pressure in MICP-treated calcareous sand was demonstrated through comparisons.