Understanding the rheological behavior of marine clay is crucial to analyzing submarine landslides and their impact on marine resource exploitation. Dispersed bubbles in marine clay (gassy clay) and electrolytes in seawater (e.g., NaCl concentration of 0.47 M) significantly impacts rheological properties. Under low ionic strength and low pore water pressure conditions, dispersed bubbles have a strengthening effect on the yield stress and the viscosity of clays. This effect turns into a weakening effect when the pore water pressure reaches 300 kPa or the ionic strength exceeds 0.18 M. It was proposed that the effect of bubbles, whether strengthening or weakening, was determined by the size of bubbles with respect to the characteristic size of the particle structure formed by clay particles. A theoretical model was developed, which reasonably captures rheological behaviors of gassy clays.

Earthquake-induced liquefaction is a geological disaster that caused extensive damage to buildings, railways, dams. Due to the construction techniques and economic conditions, the subsurface layers of some buildings must be reinforced to resist seismic loads. Microbial-induced desaturation is a development technique which can be used for existing buildings to mitigate liquefaction. Shaking table tests were conducted to survey the effect of microbial induced desaturation on liquefaction-prone foundations beneath buildings. The test results showed that, lower saturation degree delays the generation of excess pore pressure and reduces its magnitude. It appears that the resistance to excess pressure increases as saturation degree is reduced from 100% to 93.4% or 85.6%. Desaturation prevents the decay of the amplitude of acceleration oscillations, but increases the accelerations of the structure. The settlement of the sandy soil decreases as the saturation degree decreases. Resistance to liquefaction increased by more than twice than that in the saturated sample after induced desaturation to 93.4%. The weight of the building structure contributes to the anti-liquefaction capacity.

Nanobubbles (NBs), given their unique properties, could theoretically be paired with rhamnolipids (RL) to tackle polycyclic aromatic hydrocarbon contamination in groundwater. This approach may overcome the limitations of traditional surfactants, such as high toxicity and low efficiency. In this study, the remediation efficiency of RL, with or without NBs, was assessed through soil column experiments (soil contaminated with phenanthrene). Through the analysis of the two-site non-equilibrium diffusion model, there was a synergistic effect between NBs and RL. The introduction of NBs led to a reduction of up to 24.3 % in the total removal time of phenanthrene. The direct reason for this was that with NBs, the retardation factor of RL was reduced by 1.9 % to 15.4 %, which accelerated the solute replacement of RL. The reasons for this synergy were multifaceted. Detailed analysis reveals that NBs improve RL's colloidal stability, increase its absolute zeta potential, and reduce its soil adsorption capacity by 13.3 %-19.9 %. Furthermore, NBs and their interaction with RL substantially diminish the surface tension, contact angle, and dynamic viscosity of the leaching solution. These changes in surface thermodynamic and rheological properties significantly enhance the migration efficiency of the eluent. The research outcomes facilitate a thorough comprehension of NBs' attributes and their relevant applications, and propose an eco-friendly method to improve the efficiency of surfactant remediation.