Mitigation of sand liquefaction under static loading condition using biogas bubbles generated by denitrifying...

Area of Science:

• Geotechnical Engineering
• Environmental Science
• Microbiology

Background:

• Sand liquefaction poses significant risks to infrastructure and geological stability.
• Microbial denitrification produces nitrogen bubbles, a novel pollution-free material.
• Understanding bubble behavior in soil is crucial for its application in geotechnical engineering.

Purpose of the Study:

• To assess the sustainability and distribution of biogas bubbles in sand columns.
• To evaluate the performance of biogas bubbles in mitigating sand liquefaction under static loading.
• To investigate the impact of desaturation on soil behavior and shear strength.

Main Methods:

• Laboratory experiments were conducted on sand columns.
• Biogas bubble saturation and distribution were monitored over 92 weeks.
• Static loading tests were performed to assess liquefaction mitigation under undrained conditions.

Main Results:

• Biogas bubbles exhibited excellent long-term sustainability in sand pores with minimal saturation increase.
• Bubble volume increased linearly with decreasing depth.
• Reducing saturation from 100% to ~92.4% shifted behavior from strain softening to hardening, doubling undrained shear strength.

Conclusions:

• Biogas bubbles are a stable and effective material for mitigating sand liquefaction under static loading.
• Desaturation using nitrogen bubbles is a viable method to prevent geological disasters.
• The findings highlight the potential engineering value of biogas bubbles in soil stabilization.