Mitigation of Soil Liquefaction by Microbial Method

Liquefaction Mitigation by Microbial Method 1
MITIGATION OF SOIL LIQUEFACTION BY MICROBIAL METHOD
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Liquefaction Mitigation by Microbial Method 2
Executive Summary
Occurrence of liquefaction can cause property damages, injuries or even fatalities. This
phenomenon is commonly mitigated using methods that are complex, environmentally
unfriendly and costly. Thus a need to develop and adopt easier and more sustainable methods for
mitigating liquefaction. The main aim of this project is to demonstrate microbial method as the
most efficient, eco-friendly and cost-effective approach of liquefaction mitigation. This is an
emerging method with great potential of transforming how liquefaction mitigation is done.
Implementation of this method is still low due to limited information or knowledge available.
Therefore this research will help fill this gap.
The microbial method will be applied using shaking table model tests. Various laboratory soil
tests will also be conducted to measure the permeability, shear strength, consolidation, excess
pore water pressure and deformation of the unimproved and improved soil samples. The
potential findings from the project are that microbial method improves soil liquefaction
resistance and it is more efficient, eco-friendly and cost-effective than other commonly used
liquefaction methods. These findings are expected to promote adoption of microbial method in
mitigating liquefaction.

Liquefaction Mitigation by Microbial Method 3
1. Introduction
Soil is a material that plays a key role in all engineering projects. This is because engineering
structures, such as buildings, dams, railways, highways and bridges, are either constructed on or
using soil. The suitability of soil as an engineering material is determined by its engineering
properties, including compressibility, cohesion, capillarity, elasticity, permeability, etc. These
properties are the ones that influence the stability of soil and its suitability for engineering
applications. When the soil loses its cohesion or contact force, it gets unstiffened and weak. This
results to conversion of the soil’s solid properties into liquid properties.
One of the common soil deterioration occurrences is liquefaction. This is a phenomenon
where a saturated or partly saturated loose soil substantially loses its stiffness and shear strength
as a result of increased pore pressure and decreased effective stresses. This can be caused by
excessive shaking (seismic waves) when an earthquake occurs or other sudden change in loading
or stress condition (Filali & Sbartai, 2017). When this occurs, the soil behaves as a liquid
temporarily thus losing its capacity to support weights (Shelley, et al., 2015). As stated
before, engineering properties of soil are what makes the soil suitable for various engineering
projects (Balasubramanian, 2017). This means that the possibility of soil liquefaction must
always be considered when planning for an engineering project (Hashim, et al., 2016).
When liquefaction occurs, it causes sudden movement or disturbance of the ground, which
results to loss of structural stability (Latha & Varghese, 2015). This leads to devastating
effects on the soil and the built environment, including structural damages, injuries and fatalities.
Hence the need to investigate methods of mitigating soil liquefaction cannot be overemphasized.
There are three main techniques of mitigating liquefaction: avoiding soils that are susceptible to

Liquefaction Mitigation by Microbial Method 4
liquefaction, constructing liquefaction resistant structures, and improving liquefied soil (Mishra,
(n.d.)).
Some of the techniques used for improving mechanical properties of soil include: surface
compaction, soil reinforcement, drainage methods, grouting and injection, vibration methods,
chemical stabilization, geo-membranes and geotextiles, and pre-compression & consolidation,
among others. Cost and efficiency are some of the factors that affect the choice of soil
improvement method. (Huang & Zhuoqiang, 2014). Microbial method is the most eco-
friendly and efficient method of mitigating soil liquefaction. This is a biological process
involving physical and chemical changes of the soil to modify its engineering properties (Jian,
et al., 2016).
The main goal of this project is to analyze microbial method as the most eco-friendly and
efficient method of mitigating soil liquefaction. The research paper will become a valuable
source of information regarding the cost-effectiveness and efficiency of microbial method. As a
result, the project is expected to help in preventing property damages, injuries and fatalities
resulting from soil liquefaction. Most importantly is that the factual information in this research
paper will also promote adoption of microbial method in mitigating soil liquefaction.
The succeeding sections of this research proposal are as follows: literature review; research
questions, aims/objectives and sub-goals; theoretical content/methodology; experimental set-up;
results, outcomes and relevance; project planning and Gantt chart; and conclusions.
2. Literature Review
He, et al. (2016) carried out a study to determine the suitability and reliability of using
microbial soil desaturation as an alternative technique of mitigating earthquake liquefaction. The