Experimental and Numerical Investigations on Confined Granular Systems Stabilized by Bacterial Cementation

Bacterial cementation is a relatively new technology for stabilization of granular systems where cementation happens incrementally with repeated injection of the cementation fluid through the pores of the granular media. The mechanical performance of the bacterially cemented systems is critically dependent on the spatial and temporal variations of the precipitated cement. Numerical models proposed hitherto for mechanical behavior of bacterial cementation have assumed simple homogenized cementation. This paper investigates mechanical characteristics of bacterially cemented granular materials with a view to developing reliable numerical models that incorporate the spatial and temporal variations in cementation. The numerical models are validated by controlled experiments. Sand columns have been cemented to various degrees using a bacterial system. The degree of cementation was estimated by scanning electron microscopy. Triaxial compression tests have been conducted by varying the hydrostatic pressure. A multiscale numerical model is developed to simulate the mechanical response of the cemented system. The numerical results show good agreement with the experimental observations.