The Impact of Freeze–Thaw Cycles on the Shear and Microstructural Characteristics of Compacted Silty Clay

Jia, Jia; Wei, Hongying; Yang, Dehuan; Wu, Yuancheng

doi:10.3390/buildings13092308

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…Our preliminary studies showed that the change is not obvious after five freeze-thaw cycles. Therefore, the number of freeze-thaw cycles is five in this paper, but the decreasing trend of soil shear strength is in agreement with the findings of other researchers [33,34]. For bare soil in Figure 6a, the percentage of decrease gradually tends to level off when experiencing 3 to 5 freeze-thaw cycles, which is consistent with the previous research [35].…”

Section: Effect Of the Number Of Freeze-thaw Cycles On The Shear Stre...supporting

confidence: 92%

Effect of Freeze–Thaw Cycles on the Shear Strength of Root-Soil Composite

Liu,

Huang,

Zhang

et al. 2024

Materials

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A large alpine meadow in a seasonal permafrost zone exists in the west of Sichuan, which belongs to a part of the Qinghai–Tibet Plateau, China. Due to the extreme climates and repeated freeze–thaw cycling, resulting in a diminishment in soil shear strength, disasters occur frequently. Plant roots increase the complexity of the soil freeze–thaw strength problem. This study applied the freeze–thaw cycle and direct shear tests to investigate the change in the shear strength of root-soil composite under freeze–thaw cycles. This study examined how freeze–thaw cycles and initial moisture content affect the shear strength of two sorts of soil: uncovered soil and root-soil composite. By analyzing the test information, the analysts created numerical conditions to foresee the shear quality of both sorts of soil under shifting freeze–thaw times and starting moisture levels. The results showed that: (1) Compared to the bare soil, the root-soil composite was less affected by freeze–thaw cycles in the early stage, and the shear strength of both sorts of soil was stabilized after 3–5 freeze–thaw cycles. (2) The cohesion of bare soil decreased more than that of root-soil composite with increasing moisture content. However, freeze–thaw cycles primarily influence soil cohesion more than the internal friction angle. The cohesion modification leads to changes in shear quality for both uncovered soil and root-soil composite. (3) The fitting equations obtained via experiments were used to simulate direct shear tests. The numerical results are compared with the experimental data. The difference in the soil cohesion and root-soil composite cohesion between the experiment data and the simulated result is 8.2% and 17.2%, respectively, which indicates the feasibility of the fitting equations applied to the numerical simulation of the soil and root-soil composite under the freeze–thaw process. The findings give potential applications on engineering and disaster prevention in alpine regions.

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Section: Effect Of the Number Of Freeze-thaw Cycles On The Shear Stre...supporting

confidence: 92%

Effect of Freeze–Thaw Cycles on the Shear Strength of Root-Soil Composite

Liu,

Huang,

Zhang

et al. 2024

Materials

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“…The cohesion first increases and then decreases with the increasing freeze-thaw cycles. After 30 freeze-thaw cycles, the cohesion of the soil samples is 4.34 kPa (C85), 7.93 kPa (C90) and 11.76 kPa (C95) respectively, which are 71.4%, 60.1% and 54.4% lower than the soil samples without freeze-thaw cycles (The experimental results are the same as Jia research 30 ). The cohesion first increases because small-size soil particles and salt crystals accumulate into large www.nature.com/scientificreports/ soil aggregates that contain soil and salt during the short-term freeze-thaw cycles (< 7), which enhances the bond strength between particles.…”

Section: Cohesionmentioning

confidence: 74%

Changing of mechanical property and bearing capacity of strongly chlorine saline soil under freeze-thaw cycles

Ding,

Li,

Kong

et al. 2024

Sci Rep

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Freeze-thaw cycles and compactness are two critical factors that significantly affect the engineering properties and safety of building foundations, especially in seasonally frozen regions. This paper investigated the effects of freeze-thaw cycles on the shear strength of naturally strongly chlorine saline soil with the compactness of 85%, 90% and 95%. Three soil samples with different compactness were made. Size and mass changes were measured and recorded during freeze-thaw cycles. Shear strength under different vertical pressures was determined by direct shear tests, and the cohesion and friction angle were measured and discussed. Microstructure characteristic changes of saline soil samples were observed using scanning electron microscopy under different freeze-thaw cycles. Furthermore, numerical software was used to calculate the subsoil-bearing capacity and settlement of the electric tower foundation in the Qarhan Salt Lake region under different freeze-thaw cycles. Results show that the low-density soil shows thaw settlement deformation, but the high-density soil shows frost-heaving deformation with the increase in freeze-thaw cycles. The shear strength of the soil samples first increases and then decreases with the increase in freeze-thaw cycles. After 30 freeze-thaw cycles, the friction angle of soil samples is 28.3%, 29.2% and 29.6% lower than the soil samples without freeze-thaw cycle, the cohesion of soil samples is 71.4%, 60.1% and 54.4% lower than the samples without freeze-thaw cycle, and the cohesion and friction angle of soil samples with different compactness are close to each other. Microstructural changes indicate that the freeze-thaw cycle leads to the breakage of coarse particles and the aggregation of fine particles. Correspondingly, the structure type of soil changes from a granular stacked structure to a cemented-aggregated system. Besides, the quality loss of soil samples is at about 2% during the freeze-thaw cycles. Results suggest that there may be an optimal compactness between 90 and 95%, on the premise of meeting the design requirements and economic benefits. This study can provide theoretical guidance for foundation engineering constructions in seasonally frozen regions.

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Consideration of Different Soil Properties and Roughness in Shear Characteristics of Concrete–Soil Interface

Wang,

Ni,

Hou

et al. 2024

Buildings

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To investigate the impact of diverse soil characteristics and surface irregularities on interfacial shear strength attributes, a large-scale straight shear apparatus and particle flow software were employed to conduct interfacial shear experiments with varying soil properties and surface irregularities. The results demonstrated that, under an identical R and normal stress conditions, the clay and silty clay shear stress–displacement curves exhibited strain softening, while the silt curve exhibited strain hardening. An increase in R can markedly enhance the peak shear strength at the interface, although a critical value exists beyond which this effect is no longer observed. The Rc is primarily contingent upon the soil properties. Numerical simulations demonstrate that the internal shear displacement and deformation resulting from the diverse soil properties are distinct. Clay particles are constituted of varying-sized particle aggregates that collectively resist shear. Silt particles resist shear through interfacial friction generated by shear. The practicality of Duncan and Clough’s constitutive model for interfacial shear with roughness influence is verified, and the constitutive model under strain hardening is modified.

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The Impact of Freeze–Thaw Cycles on the Shear and Microstructural Characteristics of Compacted Silty Clay

Cited by 3 publications

References 30 publications

Effect of Freeze–Thaw Cycles on the Shear Strength of Root-Soil Composite

Effect of Freeze–Thaw Cycles on the Shear Strength of Root-Soil Composite

Changing of mechanical property and bearing capacity of strongly chlorine saline soil under freeze-thaw cycles

Consideration of Different Soil Properties and Roughness in Shear Characteristics of Concrete–Soil Interface

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