Microstructure and Permeability of Bentonite-Modified Loess after Wetting–Drying Cycles

Xu, Jian; Li, Yanfeng; Bao, Wang; Wang, Zefeng; Wang, Songhe

doi:10.1061/ijgnai.gmeng-7726

Cited by 8 publications

(3 citation statements)

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“…Many previous studies have focused on the ksat of soils, which are widely used in engineering practices under freeze-thaw and wetting-drying cycles [14][15][16][17][18][19]. For the freeze-thaw cycles, Kim and Daniel (1992) [14] studied the effects of compaction degree and water content on the ksat of clay after 0 and 5 freeze-thaw cycles.…”

Section: Referencesmentioning

confidence: 99%

“…An increase in ksat was observed due to the volumetric shrinkage strain induced by the increased clay content. Thyagaraj and Julina (2019) [18] reported that the ksat of compacted clay increased with the rise in pore fluid concentrations Many previous studies have focused on the k sat of soils, which are widely used in engineering practices under freeze-thaw and wetting-drying cycles [14][15][16][17][18][19]. For the freezethaw cycles, Kim and Daniel (1992) [14] studied the effects of compaction degree and water content on the k sat of clay after 0 and 5 freeze-thaw cycles.…”

Section: Referencesmentioning

confidence: 99%

“…Thyagaraj and Julina (2019) [18] reported that the k sat of compacted clay increased with the rise in pore fluid concentrations and the number of wetting-drying cycles. Xu et al (2023) [19] studied compacted loess with 15% bentonite after wetting-drying cycles, finding that the k sat initially increased and then stabilized after five cycles. It should be pointed out that the k sat of modified tailings, subjected to freeze-thaw cycles and wetting-drying cycles, has not been deliberately studied, although it is crucial for water infiltration and the barrier effect of the capillary barrier structure.…”

Section: Referencesmentioning

confidence: 99%

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Effect of Freeze–Thaw and Wetting–Drying Cycles on the Hydraulic Conductivity of Modified Tailings

Meng,

Xia,

Xia

et al. 2024

Geosciences

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Mine tailings have shown viability as the fine–grained layer in a capillary barrier structure for controlling acid mine drainage in a circular economy. Their saturated hydraulic conductivities (ksat) under wetting–drying cycles and freeze–thaw cycles remain unexplored. In this study, modified tailings with a weight ratio of 95:5 (tailings/hydrodesulfurization (HDS) clay from waste–water treatment) and an initial water content of 12% were used. The ksat of specimens was measured after up to 15 wetting–drying cycles, each lasting 24 h, with a drying temperature of 105 °C. The ksat for wetting–drying cycles decreased from 3.9 × 10−6 m/s to 9.5 × 10−7 m/s in the first three cycles and then stabilized in the subsequent wetting–drying cycles (i.e., 5.7 × 10−7 m/s–6.3 × 10−7 m/s). Increased fine particles due to particle breakage are the primary mechanism for the ksat trend. In addition, the migration of fines and their preferential deposition near the pore throat area may also promote this decreasing trend through the shrinking and potentially clogging–up of pore throats. This could be explained by the movement of the meniscus, increased salinity, and, subsequently, the shrinkage of the electrical diffuse layer during the drying cycle. Similar specimens were tested to measure ksat under up to 15 freeze–thaw cycles with temperatures circling between −20 °C and 20 °C at 12 h intervals. Compared to the untreated specimen (i.e., 3.8 × 10−6 m/s), the ksat after three freeze–thaw cycles decreased by 77.6% (i.e., 8.5 × 10−7 m/s) and then remained almost unchanged (i.e., 5.6 × 10−7 m/s–8.9 × 10−7 m/s) in subsequent freeze–thaw cycles. The increased fine grain content (i.e., 3.1%) can be used to explain the decreased ksat trend. Moreover, the migration of fines toward the pore throat area, driven by the advancing and receding of ice lens fronts and subsequent deposition at the pore throat, may also contribute to this trend.

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