Centrifuge Modeling of Soil-Structure Interaction with MICP Improved Soil

Liquefaction-induced settlement due to earthquakes can cause significant damage to supported infrastructure, with the settlement mechanisms mobilized depending on the characteristics of the soil profile, ground motion, and structure. Microbially induced calcite precipitation (MICP) has been shown to mitigate liquefaction and reduce settlements in previous centrifuge studies. This study conducted a series of 1-m centrifuge tests at the University of California, Davis (UCD) Center for Geotechnical Modeling (CGM) to evaluate soil-structure interaction (SSI) of a simple foundation system on loose Ottawa F65 sand (D_r < 40%) with a finite MICP-treated zone. A simple rigid structure, designed to be susceptible to rocking when subjected to a 1-Hz motion, was used. A high-speed camera motion tracking system was developed to measure the lateral and vertical movements of the structure during shaking. This non-contact system eliminated all instrumentation physically connected to the structure, which ensured that the measurement system did not affect the structure performance. Accelerometers and pore pressure transducers were embedded within the underlying soil to capture the dynamic system response. Results show how a finite MICP-treated zone beneath a structure can help reduce the structure settlement and loading experienced.