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Induced Polarization for Characterizing and Monitoring Soil Stabilization Processes
Citation:
Saneiyan, S., D. Ntarlagiannis, AND D Werkema. Induced Polarization for Characterizing and Monitoring Soil Stabilization Processes. 2017 AGU Fall Meeting, New Orleans, LA, December 11 - 15, 2017.
Impact/Purpose:
Soil stabilization is critical in addressing engineering problems related to building foundation support, road construction and soil erosion among others. Microbial induced carbonate precipitation (MICP) is a method that enhances the soil strength through biomineralization of calcium carbonate (calcite). Verification of a successful soil stabilization project is often challenging as treatment areas are spatially extensive and invasive sampling is expensive, time consuming and limited to sporadic points at discrete times. The geophysical method, induced polarization (IP), is sensitive to mineral surface properties, hence a promising method to monitor soil stabilization projects.
Description:
Soil stabilization is critical in addressing engineering problems related to building foundation support, road construction and environmental problems such as soil erosion and permeability controls, among others. To increase soil strength, the stiffness of the soil is enhanced through injection/precipitation of chemical agents or minerals. Methods such as cement injection and microbial induced carbonate precipitation (MICP) are commonly applied. Verification of a successful soil stabilization project is often challenging as treatment areas are spatially extensive and invasive sampling is expensive, time consuming and limited to sporadic points at discrete times. The geophysical method, complex conductivity (CC), is sensitive to mineral surface properties, hence a promising method to monitor soil stabilization projects. Previous laboratory work has established the sensitivity of CC on MICP processes. We performed a MICP soil stabilization project and collected CC data for the duration of the treatment (15 days). Subsurface images show small, but very clear changes, in the area of MICP treatment; the changes observed fully agree with the bio-geochemical monitoring, and previous laboratory experiments. Our results strongly suggest that CC is sensitive to field MICP treatments. Finally, our results show that good quality data alone are not adequate for the correct interpretation of field CC data, at least when the signals are low. Informed data processing routines and the inverse modeling parameters are required to produce optimal results
