关键词: 微生物诱导碳酸钙沉淀, 颗粒级配, 不均匀系数, 无侧限抗压强度, SEM

Abstract: The particle gradation of soil is different, and the MICP-treated effect may be different. In this paper，the sand with particle size range of 0.074-2.0 mm was divided into four groups with good particle gradation and poor particle gradation. The unconfined compressive strength, permeability coefficient, porosity, calcium carbonate precipitation of the sand samples after curing were tested respectively. So the effects of particle gradation on mechanical properties of MICP-treated sand were compared from the macroscopic point of view. At the same time, combined with electron microscope scanning, the influence mechanism was analyzed from the microscopic point of view. The results showed that the sand of good particle gradation is better than the sand of poor particle gradation, because its amount and uniformity of calcium carbonate precipitation is better, and the porosity and permeability coefficient are smaller, thus increasing the unconfined compressive strength of the sample. This can be explained that the well-graded sand contains a better group of coarse and fine particles, which can provide more favorable deposition sites for calcium carbonate, and the silting calcium carbonate is denser and stronger.

Key words: microbial induced carbonate precipitation (MICP), particle gradation, non-uniform coefficient, unconfined compressive strength, SEM