State of the Art Review of Emerging and Biogeotechnical Methods for Liquefaction Mitigation in Sands

Abstract

Earthquake-induced liquefaction causes soil to exhibit fluidlike behavior due to a sudden increase in pore water pressure and a concurrent decrease in effective stress. The liquefaction can destroy or damage existing substructures and superstructures that results in considerable economic and human losses. Hence, there is a need for ground improvement in liquefiable soils for liquefaction hazard mitigation. Various conventional methods, such as soil replacement, densification, and grouting have been used for liquefaction mitigation historically. However, these methods are carbon-intensive, uneconomic, and environmentally unfriendly. Recently, some researchers have demonstrated new techniques that can significantly mitigate liquefaction and achieve cost-effectiveness, are ecologically friendly, and have less associated disturbances. The objective of this review is to provide an overview and the associated challenges of emerging techniques that increase the liquefaction resistance of sandy soils. Initially, the advantages and disadvantages of conventional methods are discussed to justify the requirement for advanced methods. The rapid evolution of novel materials and techniques, as well as multidisciplinary collaborations, has led to new and innovative advanced methods for effective mitigation of liquefaction. Among these methods, the biogeotechnological methods that have received great attention recently are discussed in detail. Many studies have reported the effects of biotreatment on soil properties and liquefaction resistance, factors affecting the biocementation process, and various challenges associated with the biocementation methods. Finally, additional research directions needed for biogeotechnical methods to be effective, sustainable, and resilient for liquefaction mitigation in actual field applications are presented. © 2020 American Society of Civil Engineers.