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Horizontal frost heave disasters frequently occur in cold-region engineering projects, making it essential to understand water migration mechanisms along horizontal directions during freezing processes. Using a selfdeveloped one-dimensional visualization horizontal freezing apparatus, unidirectional horizontal freezing tests were conducted on soft clay under varying temperature gradients, and the development process of the cryostructures was continuously observed. The results indicate that the thermal-hydraulic processes, including temperature evolution, water content variation, pore-water pressure dynamics, and soil pressure changes, demonstrate similarities to vertical freezing patterns, with temperature gradients primarily influencing the magnitude of parameter variations. Under the influence of gravity, the freezing front forms an angle with the freezing direction, attributed to differential freezing rates within soil strata. Post-freezing analysis showed dualdirectional water redistribution (horizontal and vertical), with horizontal migration dominating. Maximum water content was observed 1-3 cm from the freezing front. Distinct cryostructures formed in frozen zones were identified as products of tensile stresses generated by low-temperature suction and crystallization forces. The study highlights the coupling of water transfer, thermal changes, mechanical stresses, and structural evolution during freezing and suggests that water migration and cryostructure formation are interrelated processes. This research provides robust experimental evidence for advancing the theoretical framework of horizontal water migration mechanisms in frozen soil systems.

期刊论文 2025-08-01 DOI: 10.1016/j.coldregions.2025.104511 ISSN: 0165-232X

Using steel slag concrete (SSC) as a pile material not only promotes industrial waste recycling but also improves ground conditions through its distinct hydrological and chemical properties. This study investigated the hydrological processes of SSC piles under no-load conditions, offering new insights into pile-soil interactions. A novel visualization test device was developed to continuously monitor water migration, pore water pressure fluctuations, and soil disturbance over six months. Macro-scale observations and micro-scale analyses were conducted to elucidate physical and chemical reactions at the pile-soil interface. Compared to ordinary concrete piles, SSC piles demonstrated superior expansion and drainage capabilities, characterized by enhanced radial and vertical water flow, increased surface porosity, and the formation of a distinct interface layer enriched with calcium carbonate and cementitious hydration products. These improvements facilitate effective water distribution and drainage while reinforcing the pile-soil bond, thereby contributing to a more robust composite system for ground improvement. This integrated approach and its findings offer valuable contributions to the broader field of soil-pile interactions by detailing the multi-scale mechanisms governing the hydrological behavior and interface evolution of composite foundation systems.

期刊论文 2025-06-01 DOI: 10.1007/s10706-025-03124-z ISSN: 0960-3182

The shear strength index of seasonally frozen soil is significantly affected by the freezing-thawing and water replenishment methods. To simulate the actual freeze-thaw and water replenishment process in seasonally frozen soil, a new method called the unidirectional freeze-thaw and natural water replenishment method was proposed. A test device was developed to facilitate this method. By using soil as the medium for water migration, the temperature change and water migration characteristics during the freeze-thaw process were investigated. The study also considered the influence of the samples' water content and the gradient between the water content of the test samples and the water replenishment soil layer. The changes in the soil stress-strain curve, static strength, and shear strength index under freeze-thaw were analyzed based on triaxial tests. The results revealed that the temperature change during the test process can be divided into six stages: rapid cooling, slow cooling, temperature stability, slow heating, continuous phase change around 0 degrees C, and positive temperature stability. After freeze-thaw, the sample water content without gradient increased by approximately 0.6%, while the sample water content with a gradient increased by about 1.5%. However, the distribution characteristics of the water content were different. The static strength, cohesive force, and internal friction angles were all lower after freeze-thaw under different water content conditions. The maximum static strength and cohesion decreased by approximately 50% and 60%, respectively, under freeze-thaw, while the internal friction angle showed a slight decrease. The new freeze-thaw and natural water supplement method can serve as a basis for selecting the shear strength index of seasonally frozen soil.

期刊论文 2025-05-10 DOI: 10.1007/s11600-025-01566-w ISSN: 1895-6572

The freeze-thaw cycle poses a significant threat to foundations and roadbeds in seasonally frozen regions. This article conducts model experiments to analyze changes in the temperature field, water migration patterns, and settlement deformation characteristics of sand-gravel replacement foundations during freeze-thaw cycles. The experimental findings indicate that the low-temperature zone primarily exists within the sand-gravel replacement layer at the base of the slope. As the number of freeze-thaw cycles increases, the freezing depth of the sand-gravel replacement layer continues to rise. During the cooling phase, changes in soil volume moisture content result from self-weight and water migration during freezing. With an increase in the number of freeze-thaw cycles, the moisture content of external measurement points on the embankment rises at the end of the freezing period, whereas the moisture content of internal measurement points decreases. At the end of the thawing phase, measurement point 6 experiences an increase in moisture content due to the upward migration of water in the lower soil layer, while other measurement points exhibit reduced moisture content. The foundation's settlement deformation exhibits a horizontal tilted shape, with cumulative settlement amounts and settlement deformation rates determined at various positions. These results suggest that the settlement deformation tends to stabilize one month after the completion of embankment filling construction. The maximum freezing depths at the left and right slope toe positions are 1 m and 1.2 m, respectively. Furthermore, the maximum frost heave at the slope toe position is less than the maximum thawing settlement, illustrating the irreversible soil deformation following freeze-thaw cycles.

期刊论文 2025-03-01 DOI: 10.1007/s10064-025-04163-9 ISSN: 1435-9529

Coral sand, as a kind of filling material, is widely used in the construction of artificial reefs or roadbeds in coastal areas. With the widespread use of the artificial grounding freezing method in the coastal area and the seepage environment faced, it will exert a significant impact on the macroscopic properties and micro-structure of coral sand. To study the macroscopic and microscopic properties of coral sand subjected to freeze-thaw with and without seepage, the one-dimensional soil column freezing test, scanning electron microscope, direct shear test, and particle sieve test were carried out. The test results showed that there was obvious water migration in the coral sand during the freezing process, and the increase of water content in the frozen zone was large in the absence of seepage, while the difference of water content in the frozen zone, phase-transition zone and unfrozen zone of coral sand was not significant under seepage effect. The scouring effect of seepage resulted in increased friction on the surface of sand particles, and the small particles produced by freeze-thaw damage of large particles increased inter-particle shading, resulting in greater shear strength of coral sands with seepage than without seepage. Regardless of the effect of seepage, all zones of the coral sand increased in the range of particle size from 0.5 mm to 0.25 mm and decreased in the range of particle size from 0.2 mm to 0.1 mm. Freezing increased the number of small pores within the coral sand. This study provides a reference basis for understanding the macro and micro mechanical properties of artificially frozen coral sand under seepage.

期刊论文 2025-01-10 DOI: 10.1016/j.conbuildmat.2024.139441 ISSN: 0950-0618

Silty clay is widely distributed in seasonally frozen zones in China and frequently engages in engineering projects. Nevertheless, it exhibits significant frost susceptibility and generates substantial related freezing damage. To address this problem, this study investigates the impact of nano-zinc oxide (ZnO) on silty clay's frost heave characteristic. We conducted tests on silty clay with varying nano-ZnO contents, assessing plasticity limit, liquid limit, frost heave, and uniaxial compressive strength. The findings reveal that: (1) the addition of nano-ZnO can decrease the free water content, and result in both the plastic limit and the liquid limit increase, and further accelerate the freezing process, which is helpful to mitigate the frost heave caused by water migration; (2) the frost heave ratio decreases with increasing nano-ZnO content within the tested range, 4.0% addition of nano-ZnO can significantly reduce frost heave by 66.96%, and transform the silty clay from extreme frost heave to frost heave; (3) with the nano-ZnO content increases, the uniaxial compressive strengths of the specimen initially increases (0%-3.0%) and subsequently decreases (4.0%), and the brittleness also becomes more pronounced. According to the results of mechanical and frost heave tests, the optimal content of nano-ZnO is ascertained to be 3.0%. The results of this study provide a promising solution to mitigate the frost heave of silty clay, particularly in regions with limited coarse-grained soil.

期刊论文 2024-11-22 DOI: 10.1155/adce/7050182 ISSN: 1687-8086

Transmedia migration of water is the key factor influencing the bond and shear mechanical properties of the interface system between soil and concrete. In numerous engineering projects, failures often occur at the soil-concrete interface, making the study of transmedia water migration in soil-concrete interface systems highly significant. This research based on the tracer properties of fluorescein to conduct a transmedia water infiltration test on silty clay-concrete interface systems. A fluorescent quantitative method was proposed to determine the moisture content within the concrete profile. The study investigated the migration of the wetting front, changes in water content, moisture distribution across the profiles of both media, and the spatial and temporal variations of soil moisture during the transmedia water migration process. The characteristics of transmedia water migration were compared under different initial soil water contents (IWC). Results demonstrated that the water distribution law of silty clay-concrete interface systems was not monotonous; notably, the water content in the interface area increased significantly. An increase in IWC inhibited the migration of the wetting front and the water content increment of the silty clay, while promoting the progression of saturation. Additionally, the water migration in the concrete was influenced by the silty clay. The proposed fluorescent quantitative method demonstrated high measurement accuracy.

期刊论文 2024-11-08 DOI: 10.1016/j.conbuildmat.2024.138472 ISSN: 0950-0618

Water migration behavior is the main cause of engineering disasters in cold regions, making it essential to understand its mechanisms and the resulting mechanical characteristics for engineering protection. This study examined the water migration process during soil freezing through both experimental and numerical simulations, focusing on the key mechanical outcomes such as deformation and pore water pressure. Initially, a series of controlled unidirectional freezing experiments were performed on artificial kaolin soil under various freezing conditions to observe the water migration process. Subsequently, a numerical model of water migration was formulated by integrating the partial differential equations of heat and mass transfer. The model's boundary conditions and relevant parameters were derived from both the experimental processes and existing literature. The findings indicate that at lower clay water content, the experimental results align closely with those of the model. Conversely, at higher water content, the modeled results of frost heaving were less pronounced than the experimental outcomes, and the freezing front advanced more slowly. This discrepancy is attributed to the inability of unfrozen water to penetrate once ice lenses form, causing migrating water to accumulate and freeze at the warmest ice lens front. This results in a higher ice content in the freezing zone than predicted by the model, leading to more significant freezing expansion. Additionally, the experimental observations of pore water pressure under freeze-thaw conditions corresponded well with the trends and peaks projected by the simulation results.

期刊论文 2024-09-01 DOI: 10.3390/app14188210

With the aggravation of climate warming, unstable soil slopes are more and more common in permafrost regions. The long-term monitoring of a slow earthflow (K178 + 530 landslide) in the Xiao Xing'an Mountains permafrost area in Northeast China was carried out. The deformation characteristics and occurrence mechanism of the landslide were studied using field investigation, on-site drilling, sensor monitoring, laboratory test, Google satellite image, unmanned aerial vehicle photogrammetry, and high-density resistivity. To analyze the variation laws of pore water pressure and effective stress and their influence on slope deformation, a coupled hydro-thermo-mechanical model was established to reconstruct the deformation process of the slope. The results show that the groundwater recharge from the permafrost degradation and surface infiltration reduces the soil cohesion and internal friction angle near the main scarp and increases the soil gravity, thus providing dynamic and mechanical conditions for slope deformation. The melting of the continuous segregation ice in the active layer and surface infiltration reduces the soil strength of the sliding surface and provides deformation conditions for the start of the landslide. The combination of these two factors finally led to the occurrence of the landslide. According to its deformation mechanism, it can be judged that the landslide is a thrust-type landslide. In addition, after the melting of the segregation ice, the upper soil slides along the slope under the action of gravity, causing the sliding surface to be parallel to the slope surface. The soil near the main scarp slides downward and accumulates near the toe to form several transverse ridges. The instability of the transverse ridges produces secondary sliding which causes the toe to advance continuously. The numerical simulation results can intuitively reflect the stage deformation characteristics of the slope, pore water pressure changes, and effective stress distributions, which provides a supplement for further understanding the formation mechanism and deformation process of the landslide.

期刊论文 2024-04-01 DOI: 10.1007/s11069-024-06433-3 ISSN: 0921-030X

Root reinforcement is an effective slope protection measure due to root water absorption and soil suction. However, the coupled effect of rainfall and root reinforcement remains unclear, resulting in a challenge to evaluate slope stability in complex environments. This paper regards the root-soil composite as a natural fiber composite and quantifies its reinforcement effect using direct shear tests. The unsaturated soil seepage-stress theory was employed to simulate the effect of rainfall on water migration and the stability of spoil, overburden, and vegetated slopes. Field measurements and pore water pressure tests verified the simulation results. Furthermore, the influences of the slope angle, rainfall parameters, and vegetation cover thickness on slope stability were analyzed. The results showed the following: (1) The root reinforcement enhanced the soil's ability to resist shear deformation, substantially improving soil shear strength. The cohesion of the root-soil composite (crs = 33.25 kPa) was 177% higher than that of the engineering spoil (ces = 12 kPa) and 32.21% higher than that of the overburden soil (cos = 25.15 kPa). (2) The overburden and vegetated slopes had lower permeability coefficients and a higher shear strength than the spoil slope, and the effect was more pronounced for the latter, resulting in lower landslide risks. The water migration trend of the vegetated slope was characterized by substantial runoff and a low sediment yield. The safety factors of the spoil slope, overburden slope, and vegetated slope were 1.741, 1.763, and 1.784 before rainfall and 1.687, 1.720, and 1.763 after rainfall, respectively, indicating a significantly higher safety factor of the vegetated slope after rainfall. (3) The slope angle significantly affected slope stability, with lower safety factors observed for higher rainfall intensities and durations. Under these conditions, the slope angle should be less than 30 degrees, and the soil thickness should be 0.5 m for herbaceous vegetation and shrubs and 1.0 m for trees.

期刊论文 2024-04-01 DOI: 10.3390/f15040640
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