Microbial induced calcite precipitation (MICP), a novel bio-mediated ground improvement method, was explored to mitigate liquefaction-prone soils. Geotechnical centrifuge tests were used to evaluate cementation integrity and the response of MICP cemented... (more)

Microbial induced calcite precipitation (MICP), a novel bio-mediated ground improvement method, was explored to mitigate liquefaction-prone soils. Geotechnical centrifuge tests were used to evaluate cementation integrity and the response of MICP cemented sands to dynamic loading. The cementation integrity testing reveals a change in behavior from “soil-like” to “rock-like” with an increase in treatment level. Results from dynamic testing demonstrate a clear increase in resistance to liquefaction of MICP treated sands compared to untreated loose sand. The MICP sands were treated to varying levels of cementation (light, moderate, and heavy cementation levels), assessed using non-destructive shear wave velocity measurements. The centrifuge models were all subjected to ground motions consisting of sine waves with increasing amplitudes. Accelerations, pore pressures, and settlements were measured in the soil during shaking, and the changes in soil behavior and post-shaking shear wave velocity for soils prepared to different cementation levels were investigated. Increased resistance to liquefaction was demonstrated with a decrease in excess pore pressure ratios in the MICP treated models as well as in reduced post-shaking settlements; however, surface accelerations were amplified at heavy levels of cementation. A tradeoff between improving liquefaction resistance and minimizing undesirable higher surface accelerations needs to be considered when designing the soil improvement level. (hide)

Equipment	Component	Equipment Class	Facility
Data Acquisition Infrastructure	RESDAQ-AUX (Bender Element System and Robot Tools interface)	Other Utilities	University of California, Davis
Data Acquisition Infrastructure	RESDAQ-Main Data Acquisition System	Other Utilities	University of California, Davis
Geotechnical Centrifuge	Geotechnical Centrifuge	Geotechnical Centrifuge System	University of California, Davis
Horizontal Shaking Table	Shaking table - UCD horizontal	Shaking Table System	University of California, Davis

Brina Mortensen, "Bio-Mediated Soil Improvement and the Effect of Cementation on the Behavior, Improvement, and Performance of Sand" (view)

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