Microbial Method for Mitigating Soil Liquefaction

Microbial Method 1
METHOD OF MITIGATING SOIL LIQUEFACTION
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Microbial Method 2
ABSTRACT
The traditional methods of mitigating soil liquefaction can be costly for large-scale applications.
Research to determine the most cost-effective and eco-friendly method of mitigating soil
liquefaction is presented in this paper. The most eco-friendly and efficient mitigation of
liquefaction discussed in this research is the microbial method. Soil liquefaction can be defined
as an unexpected loss in strength in very loose to loose granular soils as a result of shaking of
ground followed by fast pore pressure increase. The combination of bioclogging and
biosaturation method is to generate biogas in the soil to minimize the level of saturation of sand
and sustain the desaturation of immobilizing bubbles of gases through the microbial process. The
biogas is generated through the process of denitrification and bioclogging is fro, a microbial
induced CaCo3 process.

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1. INTRODUCTION
This research paper is about the assessment of the most eco-friendly and efficient method of
mitigating soil liquefaction. Soil liquefaction can be defined as an unexpected loss in strength in
very loose to loose granular soils as a result of shaking of ground followed by fast pore pressure
increase. The shaking of the ground, which is normally as a result of significant horizontal
excitation and shearing of the very loose to loose soils or earthquakes, causes momentarily
dislodgement of the precarious contact of grain to the grain of the specific soil grains. The rapid
increase in the pressure of porewater usually accompany the shaking of the ground because of
the dislodgement, the weight superimposed on the ground is transferred momentarily to the
porewater since the soil loses its strength as a result of contact of grain to grain.
Liquefaction of soil and its related ground displacements resulting from the shaking caused by an
earthquake are the primary causes of damage in loose granular soils that are saturated. Numerous
failures induced by liquefaction of infrastructure facilities, buildings, and foundations like earth
dams, port facilities, and railway or highway embankments have been reported globally during
different earthquakes (Schenke, et al., 2013). Numerous liquefaction mitigation method existing
like cement mixing and compaction is normally too expensive to be used in a wide geographical
area. The most eco-friendly and efficient mitigation of liquefaction discussed in this research is
the microbial method.
2. LITERATURE REVIEW
2.1 Soil Liquefaction
Liquefaction is the state when the sandy soil that is saturated looses its shear strength because of
the consequent minimization of effective stresses and increased pore pressure. The term

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liquefaction was first used in 1936 to explain the massive failures of soil at Fort Peck Dam in
1936 and later gathered global attention in the 1960s after massive magnitude earthquakes
caused damage on structures through ground failure in Niigata, Alaska, and Anchorage. The
structure of the cohesionless oil tends to become more compact as a consequence of the cyclic
stresses applied but with a resulting minimization of the effective stresses on the soil grains and
stresses transfer to the porewater. In the event of an earthquake, the application of induced cyclic
shear stresses by the shear wave propagation result into the contraction of loose sand resulting
into the pressure of pore water (Kheirbek-Saoud & Fleureau, 2012).
The development of high pressure of water pore results in upward water flow may change the
sand into a liquefied state which is referred to as liquefaction. The liquefaction affects
transportation systems, utilities, and structures are dangerous in case appropriate measures of risk
mitigation are not adopted. Numerous methods that reduce liquefaction effects on buildings
include tying together independent footing with grade beams, application of caissons or end
bearing piles with high lateral capacities, and additional ductility to allow larger deformations.
Ground improvements through in-situ can also improve the performance during cyclic loadings,
minimizing ground displacement and liquefaction (Jakka, et al., 2010).
2.2 Mitigation Methods of Soil Liquefaction
The improvement of the soil can be attained through sand reinforcement, drainage, dewatering,
solidification, and densification. The implementation of these methods may result in partial or
full liquefaction elimination potential depending on the quantity of deformation that the building
can tolerate and the forces likely to the experienced. The selection of the suitable method of soil
improvement depends on numerous factors such as the extent of area covered, required depth,
the magnitude of improvement attainable by a specific approach, level of improvement required,