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... the present study, a relatively large soil tank with the dimension of 550 mm(L)*150 mm(W)*400 mm(D) was used to investigate the frost heave characteristics of the Komaoka soil. Fig. 3 is a photo that summarizes the components and setup of the frost heave test. A schematic diagram with labeled dimensions and details of the frost heave model test is also shown for better illustration (see Fig. 4). The main steps for conducting the frost heave test are summarized ...
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... soil specimen was generally around 265 mm. During the compaction process, 12 EC-5 moisture sensors and 12 T-type thermocouples were installed at desired locations (as shown in Figs. 3 and 4), through the 16 sensor holes (four rows with four holes on each row) that are available on the back acrylic wall of the soil tank. The moisture and temperature sensors were calibrated prior to their use. The calibration procedures were similar to those summarized in Ren et al. (2021). These sensors were connected to a data logging ...
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... 4), through the 16 sensor holes (four rows with four holes on each row) that are available on the back acrylic wall of the soil tank. The moisture and temperature sensors were calibrated prior to their use. The calibration procedures were similar to those summarized in Ren et al. (2021). These sensors were connected to a data logging system (see Fig. 3). The data logging time interval was generally 5 min during the frost heave test. After compaction and sensor installation, the top plate was placed on the top surface of the soil specimen (see Fig. 4(b)). To minimize friction, silicone grease was smeared on the four sides of the top plate before installing it. The silicon grease and ...
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... On the other hand, the PIV technique can be used to quantify full field deformation of the soil specimen. In the present study, a Panasonic digital camera, DMC-TX1, with 4864 pixels in length and 3648 pixels in width, was used to automatically capture images of the front surface of the soil specimen during the testing period (as shown in Fig. 3). The thickness of the acrylic wall of the soil tank is around 38 mm. This is assumed to have insignificant influence on the PIV deformation computation (e.g., White et al., 2001). The time interval for imaging should be small, which can ensure high correlation between consecutive image pairs. The imaging interval was generally 3 min ...
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... Therefore, the restraining bucket was improved by utilizing transparent polymer material to enable the visualization of alterations in the soil. In recent decades, various auxiliary techniques including X-ray imaging [19], CT scanning [20], fluorescence tracing [21], digital image correlation (DIC) [22], and particle image velocimetry (PIV) techniques [23,24] have been developed for capturing the characteristics of frost heaving deformation and ice segregation in soil. These experimental works have made significant contributions to elucidating the mechanisms of soil frost heave deformation while also advancing three renowned frost heave theories [5,6,13,25]: capillary theory, frozen fringe theory, and modified capillary theory. ...
Preventing and controlling frost heave deformation is critical to artificial freezing construction. Compared to road engineering, the soil experienced complex pressure and constraint conditions during the freezing process. Therefore, this study introduces a new method for measuring the volumetric frost heave coefficient (VFHC) of freezing soil under complex pressure and constraint conditions. Series experiments were performed to validate the method and explore the pressure effects. Experimental results demonstrate that this method consistently produces stable and well-reasoned outcomes, providing valuable reference for the development of specialized three-dimensional frost heave testing apparatus in subsequent research. Furthermore, this research reveals that pressure and constraint conditions have a significant influence on the volumetric frost heave deformation of soil. An empirical equation that describes the variation of the VFHC with moisture content, considering the pressure and constraint effects, was proposed. These findings have significant implications for underground engineering employing the artificial ground freezing method.
... Clear shear bands were observed during the tests. Ren et al. (2022) analyzed the frost heave characteristics of coarse-grained volcanic soils using the DIC/PIV method, in which coarse-grained soils were used as tracer particles. ...
Two challenges exist in the non-contact measurements of local frost heave of soil, such as the grayscale change caused by the generation of pore ice and the discontinuity of the deformation field caused by segregation cracks. To overcome the upper two challenges, a new imaging analysis algorithm based on the digital image correlation (DIC) method is developed in this study, leading to a modified DIC method for the deformation analysis of segregation frost heave. The proposed DIC method is applied to the segregation frost heave test in a soil column. The results demonstrate that the new algorithm can effectively reduce the differences in soil grayscale distribution and reduce the disappearance of correlation peaks due to segregation cracks. With the proposed DIC method, the non-contact measurement of frost heave deformation can achieve a resolution of less than 0.5 mm.
With the increasing number of projects in cold regions and the widespread use of artificial freezing methods, conducting research on the dynamic properties of frozen soil has become a considerable issue that cannot be avoided in permafrost engineering. Currently, the numerical simulation research on the dynamic mechanical behavior of frozen soil is less concerned with the changes in stress, strain, and particle damage inside the material. The necessary conditions for conducting this study are compatible with the core idea of smooth particle hydrodynamics (SPH). In this study, the Eulerian SPH method was modified to address numerical oscillations and errors in solid mechanics, particularly impact dynamics problems. A numerical scheme for simulating the split Hopkinson pressure bar test was developed within the modified Eulerian SPH framework and implemented using self-programming. The frozen soil dynamic mechanical behavior was simulated under three strain rates. The accuracy and superiority of the SPH method were verified through calculations and experiments. The simulation captures the stress and strain responses within the sample at different moments during the impact process, indicating that the frozen soil strain rate-strengthening effect resulted from microcrack expansion and inertial effects.
