Shaking table study of dynamic response of biotreated liquefiable sandy ground with varying slopes

Sloping saturated sandy deposits, such as submarine slopes and liquefiable shorelines, are highly vulnerable to seismic liquefaction. Microbially induced calcite precipitation (MICP) offers a sustainable ground-improvement alternative, yet its effect on the seismic behavior of inclined liquefiable sandy ground remains inadequately investigated. This study examines, through shaking table tests, the dynamic response and liquefaction mitigation of MICP-treated inclined sandy ground. Results show that MICP treatment markedly suppresses the overall slope surface settlement. Driven by gravity, the bacterial suspension and cementation solution migrated preferentially toward the slope toe, resulting in higher calcium carbonate content and a more non-uniform cementation profile. This heterogeneous cementation effectively reduced the excess pore water pressure ratio at the toe, thereby lowering its liquefaction susceptibility. The treated slope exhibited only minor crest settlement and negligible toe heave, with structural integrity largely preserved after liquefaction. This study addresses a critical gap by providing systematic shaking table evidence on the efficacy of MICP in improving liquefaction resistance in sloping sandy ground, and demonstrates that gravity-driven, non-uniform bio-cementation is central to the enhanced performance. These insights support the potential use of MICP in stabilizing vulnerable sloped ground models.