Abstract: In this study we aimed to investigate the influence of native bacteria on the strength of red clay. We cultivated the native bacteria in red clay and added this enrichment cultivated bacteria solution into remoulded red clay specimens. Through geotechnical test and electron microscopy test we examined the changes in physical and mechanical properties and microstructure of red clay. Results concluded that with the adding of bacteria, peak strength at failure and modulus of compression both increased with time and then declined. Meanwhile, SEM images showed that bacteria augmented the silty particle content in red clay, while reduced the clayey content. The research findings offer reference for further researching the influence of single bacteria on the physical and mechanical properties and microstructure of red clay.

Key words: red clay, native bacteria, cementation, shear strength, geotechnical test, electron microscopy test