Macro-micro mechanical behavior of saturated cemented sands during drained triaxial shearing

Abstract

To enhance the understanding of the macro-micro mechanical behavior of cemented sands, a series of drained triaxial shearing tests were conducted on saturated cemented sands with varying cement contents and confining stresses. These tests incorporated high-performance acoustic emission (AE) monitoring and an environmental scanning electron microscope (ESEM) technique. The results yielded quantitative interpretations of macro-mechanical response, microstructural variation, and AE behaviors. Specifically, increasing cement content led to an exponential reduction in porosity (or pore area ratio) and a power increase in pore number, possibly due to the production of hydration products that segment large pores. Relationships were established among peak strength (or AE hits), cement content, and confining stress. However, AE trends diverged from those observed in peak strength due to microstructural modifications under different cement contents and their resulting differences in micromechanical behavior during shearing. General relationships between AE rate and mechanical parameters were established during the initial shearing stage, regardless of cement content and confining stress. Moreover, AE evolution efficiently characterized subtle variations in failure patterns due to its high sensitivity to failure-induced structural modifications. These contributions have the potential to establish a non-destructive field evaluation framework and provide guidelines for the efficient utilization of cemented soils in geological and geotechnical engineering applications.