Mitigation of liquefaction hazards using the combined biodesaturation and bioclogging method

Wu, Shifan

doi:10.31274/etd-180810-4279

Cited by 5 publications

(13 citation statements)

References 118 publications

(180 reference statements)

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“…Biological mediated systems for the improvement of engineering soil properties consist of four components viz chemical reaction network, microorganism and biological activity, process controlling/monitoring and soil improvement phase as represented in figure 1 below [8]. [13] had identified potential bio-geochemical processes commonly utilized in the improvement of soil matrix are identified as bio-mineralization, bio-clogging and biogas generation.…”

Section: Bio-mediated Soil Improvementmentioning

confidence: 99%

“…Denitrification, otherwise known as microbial induced dissimilatory is a biochemical process of producing biogas and calcium carbonate precipitates through metabolic activities of denitrifying bacteria on nitrates and organic chemical compounds known as electron donors [7]; [13]. The biogases produce in denitrification process are nitrogen (N2), carbon dioxide (CO2) [36], [7].…”

Section: Microbial Denitrification Processmentioning

confidence: 99%

“…Microbial denitrification like any other enzymatic reactions are affected upon by many environmental factors [13]. These factors influence the rate of denitrification process and products formed at the end or during the process [39], [40].…”

Section: Factors Affecting Denitrification Processmentioning

confidence: 99%

“…Among the factors identified are pH [39], [40], [41]; nitrates concentration [40], [42] and medium composition [43], [40]. Other environmental factors are presence of oxygen gas [39] , pore space geometry, moisture content [13] and temperature [40].…”

Section: Factors Affecting Denitrification Processmentioning

confidence: 99%

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Bio-desaturation and bio-sealing techniques for mitigation of soil liquefaction: a review

2018

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Biogeotechnology is a recent area of study that deals with the improvement of engineering properties of soils in an eco-friendly and sustainable approach through the use of microorganisms. This paper first, reviewed the concept of bio-mediated soil improvement technique, components involved and the roles they played. Two processes of bio-mediation soil improvement techniques i.e. microbial-induced calcite precipitation (MICP) for producing bio-cement via ureolysis and bio-desaturation for generating specifically biogenic nitrogen gas via denitrification, their mechanisms of occurring and factors influencing them were described in details. An overview study was done on soil liquefaction. Conventional methods employed for mitigations of liquefaction hazards were reviewed and their limitations were drawn. The use of the de-saturation process for mitigation of soil liquefaction was adequately addressed. Mitigation of liquefaction using biological processes, in particular, MICP and/or bio-desaturation were introduced. The findings from the previous works have shown that both the two techniques are capable of improving liquefaction resistance of soils. Most of the results have shown that presence of biogenic nitrogen gas in soils treated with denitrifying bacteria is able to induce partial desaturation in the soil which consequently increases the cyclic shear strength, reduces pore water pressure and changes the soil behaviour from compressive to dilatant. Finally, potentials, challenges, and recommendations for future studies were identified.

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Section: Bio-mediated Soil Improvementmentioning

confidence: 99%

Section: Microbial Denitrification Processmentioning

confidence: 99%

Section: Factors Affecting Denitrification Processmentioning

confidence: 99%

Section: Factors Affecting Denitrification Processmentioning

confidence: 99%

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Bio-desaturation and bio-sealing techniques for mitigation of soil liquefaction: a review

2018

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“…In water flow conditions, measures should be taken to prevent the flow path through the desaturation zone to ensure the stability of gas bubbles in the soil. Wu (2015) proposed a method to use microbially induced cementation to fix the gas bubbles and control the water flow in soil, so that the desaturation state of soil can be maintained for a longer time.…”

Section: Stability Of Desaturation State In Soilmentioning

confidence: 99%

Mitigation of soil liquefaction using microbially induced desaturation

Chu

et al. 2016

J. Zhejiang Univ. Sci. A

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Soil liquefaction can cause disastrous consequences to buildings and human lives. Regular countermeasures against soil liquefaction are often overly expensive for normal buildings and structures. This could be the major reason that liquefaction induced damage is still widely encountered in large-and mid-size earthquakes in recent years. In this paper, a new method for the mitigation of soil liquefaction using the microbially induced soil desaturation is proposed and tested. The desaturation effect in soil is achieved by the generation of nitrogen gas produced from the microbial denitrification process. Some major issues related to this method are experimentally investigated. These include soil desaturation procedures, shapes and distribution of gas bubbles in soil, mechanical responses and liquefaction resistance of desaturated soils, and stability of gas in soils. The desaturation treatment of soils is made simply by introducing denitrifying bacteria and a desaturation solution into soil pores by mixing, flushing, or injection. The degree of saturation can be reduced as the microbial reaction proceeds. Experimental results show that the final degree of saturation is related to the initial nitrate concentration added to the soil: the higher the concentration of nitrate in the desaturation solution, the lower the degree of saturation that can be achieved. The existence of gas bubbles in soil is evidenced by computer tomography (CT) technology. The CT images reveal that gas is in the form of small pockets which has a size a little larger than the mean size of sand grains. It is shown in the shaking table tests that microbially induced desaturation can effectively improve the liquefaction resistance of soil by showing a much lower pore pressure generation, much smaller volumetric strain, and much smaller settlement of the structure in desaturated soil, as compared with those in saturated soil. Triaxial consolidated undrained tests reveal that the desaturation treatment of soil can improve the undrained shear strength of loose sand. The stability of gas is tested under hydrostatic and water flow conditions. The gas phase is stable under the hydrostatic condition, but unstable under water flow conditions. So measures ought to be taken to prevent steady flow in practice.

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Recent development in biogeotechnology and its engineering applications

Cui

Chu

2021

Front. Struct. Civ. Eng.

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Microbial geotechnology or biogeotechnology is a new branch of geotechnical engineering. It involves the use of microbiology for traditional geotechnical applications. Many new innovative soil improvement methods have been developed in recent years based on this approach. A proper understanding of the various approaches and the performances of different methods can help researchers and engineers to develop the most appropriate geotechnical solutions. At present, most of the methods can be categorized into three major types, biocementation, bioclogging, and biogas desaturation. Similarities and differences of different approaches and their potential applications are reviewed. Factors affecting the different processes are also discussed. Examples of up-scaled model tests and pilot trials are presented to show the emerging applications. The challenges and problems of biogeotechnology are also discussed.

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Mitigation of liquefaction hazards using the combined biodesaturation and bioclogging method

Cited by 5 publications

References 118 publications

Bio-desaturation and bio-sealing techniques for mitigation of soil liquefaction: a review

Bio-desaturation and bio-sealing techniques for mitigation of soil liquefaction: a review

Mitigation of soil liquefaction using microbially induced desaturation

Recent development in biogeotechnology and its engineering applications

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