Solidification effect and mechanism of ionic soil stabilizer applied on high-water-content clay: Fid-Bau Portal

Solidification effect and mechanism of ionic soil stabilizer applied on high-water-content clay

Wu, Xue-Ting / Qi, Yi / Chen, Bin

Abstract The in situ solidification of soft clay deposits and reclamation of dredged clays are challenging due to the high water content and low strength. An eco-friendly ionic soil stabilizer (ISS) was used to stabilize a saturated soft mucky clay with high water content. The ISS-solidification effect was investigated by a series of physical and mechanical tests and microscopic tests. The results demonstrated that ISS had a good solidification effect on high-water-content raw clay with the increase in unconfined compressive strength (+48.0%) and vertical yield stress (+66.7%), and with the decrease in plasticity index (-29.6%), compression index (-34.2%) and compressibility coefficient (-22.6%) at the optimal dilution volume ratio. Besides, the ISS clay solidification micro-mechanism was studied by use of a series of microscopic tests. The results showed that there was no new mineral or oxide formed after ISS-clay solidification, except for the new element C with the content of 19.92% observed in the solidified specimen, which was ascribed to the hydrocarbon radical in ISS. However, Ca$$^{2+}$$ and Mg$$^{2+}$$ on clay colloid surfaces were replaced by Fe$$^{3+}$$, Al$$^{3+}$$, K$$^{+}$$, and Na$$^{+}$$ in ISS diluent during the curing process. The micro-mechanism can be interpreted as the reducing d-value in clay mineral and cation exchanging on clay colloid surfaces, and then, the special binary molecular structure of sulfonated oil in ISS lead to a breakdown of double electric layer structure and expulsions of interlayer, bound and free water from clay, which contributed to the close arrangement and compact aggregation of clay minerals.