The Utilisation of Colloidal Silica Grout in Soil Stabilisation and Liquefaction Mitigation: A State of the Art Review

Krishnan, J. Murali; Shukla, Shruti

doi:10.1007/s10706-020-01651-5

Cited by 13 publications

(3 citation statements)

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“…Colloidal silica grouting is an environmentally conscious ground improvement technique capable of improving the engineering properties of rock and soil for applications including earthquake-induced liquefaction mitigation, groundwater flow control, and rock fracture sealing 1 – 11 . The process can be initiated by supplying a low viscosity suspension of non-porous, spherical silica nanoparticles to soils, with the formation of a silica gel occurring over time at a rate controlled by initial suspension chemistry 3 , 12 .…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies have examined the stability of colloidal silica suspensions and the time-dependent formation of silica gels for a diverse range of applications spanning from soil improvement to food processing 11 , 19 , 20 . Collectively, these studies have demonstrated that the time required to achieve gel formation can be controlled by varying the composition of colloidal silica suspensions, including through differences in initial pH, ion concentrations, colloidal silica concentrations, and the size of included colloids 1 , 3 , 12 , 21 , 22 .…”

Section: Introductionmentioning

confidence: 99%

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Biomediated control of colloidal silica grouting using microbial fermentation

Gomez,

Muchongwe,

Graddy

2023

Sci Rep

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Colloidal silica grouting is a ground improvement technique capable of stabilizing weak problematic soils and achieving large reductions in soil hydraulic conductivities for applications including earthquake-induced liquefaction mitigation and groundwater flow control. In the conventional approach, chemical accelerants are added to colloidal silica suspensions that are introduced into soils targeted for improvement and the formation of a semi-solid silica gel occurs over time at a rate controlled by suspension chemistry and in situ geochemical conditions. Although the process has been extensively investigated, controlling the rate of gel formation in the presence of varying subsurface conditions and the limited ability of conventional methods to effectively monitor the gel formation process has posed practical challenges. In this study, a biomediated soil improvement process is proposed which utilizes enriched fermentative microorganisms to control the gelation of colloidal silica grouts through solution pH reductions and ionic strength increases. Four series of batch experiments were performed to investigate the ability of glucose fermenting microorganisms to be enriched in natural sands to induce geochemical changes capable of mediating silica gel formation and assess the effect of treatment solution composition on pH reduction behaviors. Complementary batch and soil column experiments were subsequently performed to upscale the process and explore the effectiveness of chemical, hydraulic, and geophysical methods to monitor microbial activity, gel formation, and engineering improvements. Results demonstrate that fermentative microorganisms can be successfully enriched and mediate gel formation in suspensions that would otherwise remain highly stable, thereby forgoing the need for chemical accelerants, increasing the reliability and control of colloidal silica grouting, enabling new monitoring approaches, and affording engineering enhancements comparable to conventional colloidal silica grouts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Biomediated control of colloidal silica grouting using microbial fermentation

Gomez,

Muchongwe,

Graddy

2023

Sci Rep

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“…Most of them refer to experimental studies on small-size soil elements, while others refer to physical models and field tests. These studies have allowed rapid development with non-stop updates of knowledge on CS grouting, as recently highlighted in [40,41].…”

Section: Introductionmentioning

confidence: 99%

Effects of Colloidal Silica Grouting on Geotechnical Properties of Liquefiable Soils: A Review

2021

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Colloidal silica (CS) is a kind of nanomaterial used in soil/rock grouting techniques in different branches of civil engineering. Many studies have recently been performed to investigate the potential of CS in improving the mechanical behavior of cohesionless soils and mitigating the risk of seismic liquefaction in urbanized areas. CS grout is chemically and biologically inert and, when injected into a subsoil, it can form a silica gel and stabilize the desired soil layer, thus representing an attractive, environmentally friendly alternative to standard chemical grouting techniques. This paper firstly describes the characteristics of CS grout, the gelation process and the main features of the behavior of the pure gelled material. The grout delivery mechanisms through porous media are then explained, pointing out the crucial issues for practical application of CS grouting. All the grouting-induced effects on the soil behavior, which have been investigated by laboratory tests on small-sized soil elements, are reviewed, including the modifications to soil strength and stiffness under both static and seismic loading conditions, to soil compressibility and hydraulic conductivity. Published results from physical model tests and in situ applications are also presented. Finally, some aspects related to the mechanism of soil improvement are discussed. A critical discussion of each topic is presented, drawing particular attention to the controversial or not yet fully examined aspects to which future research on colloidal silica grouting should be directed.

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