Abstract
Sinkholes are among the most significant karst-related hazards, arising from the dissolution of soluble rock and subsequent collapse of overlying geomaterials, thereby compromising rock mass stability and underground infrastructure. Conventional sinkhole remediation approaches often rely on cement-based grouting to prevent failure; however, the associated environmental impacts underscore the need for eco-friendly and sustainable alternatives such as biocementation. While biocementation has been a widely applied technique in reinforcing soils and cemented structures, the potential of biocemented hybrid soil-embedded karstified rock systems remains unexplored. To address sinkhole-related post-hazard remediation, this work investigates the potential of biocementation as a sustainable reinforcement strategy for sinkhole-susceptible rock masses, involving granular infill of subsurface cavities followed by enzyme-induced calcite precipitation (EICP). Limestone-based hybrid rock specimens will be designed, containing sand-filled cavities treated with EICP, and subsequently, the specimens will be subjected to uniaxial compression tests to characterize their mechanical response and Micro-computed tomography (μ-CT) scans for microstructural evolution. Results show that EICP-biocementation increased the unconfined compressive strength (UCS) of the specimens with cavity reinforcement by up to 57%, while micro-CT analysis revealed significant occlusion of limestone microporosity in treated specimens. These findings demonstrate the potential of biocementation in the repair of sinkhole-susceptible rocks with cavities by transforming dissolution-induced cavities into coherent, load-bearing zones, offering a sustainable biogeotechnical approach for stabilizing sinkhole-prone strata and protecting subsurface infrastructure.
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DOI
https://doi.org/10.5038/9781967518012.1005
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Biogeomechanics of EICP Reinforcement of Karstified Rock Masses
Sinkholes are among the most significant karst-related hazards, arising from the dissolution of soluble rock and subsequent collapse of overlying geomaterials, thereby compromising rock mass stability and underground infrastructure. Conventional sinkhole remediation approaches often rely on cement-based grouting to prevent failure; however, the associated environmental impacts underscore the need for eco-friendly and sustainable alternatives such as biocementation. While biocementation has been a widely applied technique in reinforcing soils and cemented structures, the potential of biocemented hybrid soil-embedded karstified rock systems remains unexplored. To address sinkhole-related post-hazard remediation, this work investigates the potential of biocementation as a sustainable reinforcement strategy for sinkhole-susceptible rock masses, involving granular infill of subsurface cavities followed by enzyme-induced calcite precipitation (EICP). Limestone-based hybrid rock specimens will be designed, containing sand-filled cavities treated with EICP, and subsequently, the specimens will be subjected to uniaxial compression tests to characterize their mechanical response and Micro-computed tomography (μ-CT) scans for microstructural evolution. Results show that EICP-biocementation increased the unconfined compressive strength (UCS) of the specimens with cavity reinforcement by up to 57%, while micro-CT analysis revealed significant occlusion of limestone microporosity in treated specimens. These findings demonstrate the potential of biocementation in the repair of sinkhole-susceptible rocks with cavities by transforming dissolution-induced cavities into coherent, load-bearing zones, offering a sustainable biogeotechnical approach for stabilizing sinkhole-prone strata and protecting subsurface infrastructure.