Microscopic analysis of deformation and water–salt transport in chlorine saline soils under unidirectional freezing in cold and arid zones

Journal of Rock Mechanics and Geotechnical Engineering, Journal Year: 2024, Volume and Issue: unknown

Published: July 1, 2024

Sudden temperature drops cause soils in natural environments to freeze unidirectionally, resulting soil expansion and deformation that can lead damage engineering structures. The impact of temperature-induced freezing on solute migration saline soils, especially under extended freezing, is not well understood due the lack knowledge regarding microscopic mechanisms involved. This study investigated expansion, deformation, water–salt chlorinated materials commonly used for canal foundations cold arid regions, different roof temperatures compaction levels through unidirectional experiments. structures were observed using scanning electron microscopy (SEM) optical microscopy. A quantitative analysis microstructural data was conducted before after elucidate deformation. results indicate swelling enhanced by elevated approaching soil's point compaction, which prolongs duration accelerates rate migration. altered microstructure continuous gradients, leading four distinct zones: frozen zone, peak gradual unfrozen each exhibiting significant changes pore types fractal dimensions. Vacuum suction at colder end structure facilitates upward salt water, subsequently undergoes crystallization. process expands internal causes swelling. findings provide a theoretical basis understanding evolution regions management engineering.

Language: Английский

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Investigating the internal erosion behavior and microscopic mechanisms of chemically stabilized soil: an experimental study

Frontiers in Earth Science, Journal Year: 2024, Volume and Issue: 12

Published: Aug. 27, 2024

Introduction Internal erosion triggered by water pipeline leaks seriously threatens the stability of urban ground. Hangzhou, a city in Zhejiang Province, China, is facing critical challenges due to ground collapse (UGC) caused internal erosion. However, there lack research on prevention UGC improving erodibility underground soil. Addressing this issue utmost importance ensure city’s and safety. This paper proposes improve typical sandy silt soils with chemical stabilisers. Methods The effects three stabilisers, lignosulphonate (LS), lime (LI), lignin fibre (LF), shear stress ( τ c ) coefficient k d were investigated, which from Zhejiang, hole test (HET) at different mixing amounts conservation times. Results findings indicate that LF mainly improves resistance increasing , maximum increase 2.38 times; LI decreasing decrease 2.18 After adding LS, did not change significantly. scanning electron microscope (SEM) revealed inclusion led formation larger agglomerates microstructure soil remained dispersed even after LS. Various stabilisers used exhibited distinct mechanisms. Sandy improved exfoliated into agglomerates, displaying high On other hand, treated still lacks protective layer shows minimal improvements its ability withstand In contrast, LS-amended remains stripped individual particles insignificant changes resistance. Discussion study can provide conceptual framework for choosing foundation treatment techniques future development projects.

Language: Английский

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Research on Solidification Methods and Stabilization Mechanisms of Sulfate Saline Soils

Applied Sciences, Journal Year: 2024, Volume and Issue: 14(16), P. 7246 - 7246

Published: Aug. 17, 2024

In cold regions, saline soils can cause dissolution, settlement, and salt expansion of the roadbed under influence freeze–thaw cycles, so they need to be stabilized during road construction. this study, lime, fly ash (FA), polyacrylamide (PAM) were used stabilize sulfate soils, subjected unconfined compressive strength test (UCS), splitting test, cycle tests (FTs). The stabilization mechanism three materials on was also studied via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), photoelectron (XPS). results showed that addition FA, PAM improve mechanical properties frost resistance soils. After 28 d curing, UCS FA-, PAM-, lime-stabilized increased by at least 55%, 23%, 1068%, respectively, 161%, 75%, 2720%, respectively. five residual ratios (BDRs) L2 (lime 8%), F2 (FA 11%), P2 (PAM 1%) 71.78%, 56.42%, 39.05%, 17.95%, decreasing trend tended stable. lime FA chemically stabilized, their better than physical PAM.

Language: Английский

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Optimized Irrigation Strategies for Saline Soil Remediation in Agricultural Lands Under Water-Limited Conditions

Sustainability, Journal Year: 2024, Volume and Issue: 16(23), P. 10256 - 10256

Published: Nov. 23, 2024

Soil salinization is a prevalent global issue, significantly impacting crop cultivation and food production. This study investigates the potential of sustainably harnessing rainwater for remediation saline soils in water-scarce regions. column leaching experiments were performed to evaluate effectiveness different methods salt removal from tillage layer. The findings demonstrated that intermittent was more effective than continuous remediating NaCl-type soils. When with 27 cm applied, soil layers below 5 ranged 12.28% 26.86%. Intermittent increased rate between 44.49% 54.18%. higher desalination efficiency attributable extended soil–water contact time. time 1.5 h over 4.5 h, comparable effects produced. similar patterns Na2SO4-type However, due stronger affinity SO42− clay particles, their effluent concentration lower Cl− under same conditions. To optimize efficiency, operational parameters can be adjusted reduce depth 15 cm, interval events 24 h. this may serve as valuable reference restoration improvement efforts

Language: Английский

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Evolution characteristic of soil water in loess slopes with different slope angles

Geoenvironmental Disasters, Journal Year: 2024, Volume and Issue: 11(1)

Published: Dec. 27, 2024

Language: Английский

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