Advanced Triaxial Tests on Partially Saturated Soils Under Unconfined Conditions

Rasool, Ali Murtaza

doi:10.1007/s40999-020-00530-7

Cited by 7 publications

(1 citation statement)

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“…Recently, biotechnology, as a natural mitigation method, has been introduced as a soil improvement method against earthquake-induced liquefaction due to its generation of cohesion in granular soil and desaturation of submerged soil. The generation of cohesion is used to enhance the shear strength of soil (Liu et al, 2019; Soltani-Jigheh et al, 2020; Wen et al, 2020; Xiao et al, 2019), while the desaturation of soil, studied by many researchers (Marasini and Okamura, 2015; O’Donnell et al, 2017; Rasool and Aziz, 2020; Zeybek and Madabhushi, 2017), is used to reduce the saturation degree by producing bubble gas. The second technique can be applied to generate gas bubbles through the following methods (He et al, 2013):…”

Section: Introductionmentioning

confidence: 99%

Mitigation of liquefaction triggering due to bio-gas-induced desaturation using element tests and the strain energy approach

Baziar

Amirabadi

2021

Earthquake Spectra

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Currently, conventional remediation of liquefaction triggering may have many environmental effects, and this important issue has led researchers to look for more sustainable methods. In this research, one of the new bio-improvement methods (biogas) has been used to generate gas bubbles within a soil, susceptible to liquefaction. Using this method, two bio materials create ammonium ions and carbonate, in which ammonium ion is converted into nitrate due to the presence of bacteria in water, and they are eventually converted to nitrogen gas in an anaerobic condition. The nitrogen bubbles created in water reduce the soil’s degree of saturation, which in effect increases the soil’s resistance to liquefaction occurrence. In this study, two sources of urease enzyme were used to reduce the soil degree of saturation. The effects of various parameters, including the optimum concentration of each substance for optimum time to generate gas bubbles, as well as the effect of the oxygen amount in water were investigated using monotonic triaxial tests. The results illustrated that the addition of the mentioned two substances to the oxab (water with 60 ppm oxygen) or tap water decreased the pore water pressure due to desaturation. Finally, the energy approach was used to test the substance containing the amount of oxab with the highest decrease in pore water generation, here called “optimum selection,” in the cyclic triaxial device, and the results were analyzed to evaluate liquefaction occurrence. The outcome of these results revealed that compared with the strain energy of the non-treated sample, the treated sample had a much higher strain energy; in other words, the treated sample needed a larger amount of loading to trigger liquefaction.

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