| Citation: |
LI Qiang, LI Tonglu, LI Hua, SHEN Wei, LI Ping, ZHANG Changliang. Numerical analysis of evolution of the unsaturated soil micro-structure with capillary action during compression[J]. Hydrogeology & Engineering Geology, 2022, 49(4): 135-143. doi: 10.16030/j.cnki.issn.1000-3665.202110045
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Numerical analysis of evolution of the unsaturated soil micro-structure with capillary action during compression
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Abstract
Using numerical method to investigate the evolution of micro-structure in unsaturated soil is helpful to explain their physical mechanical. However, the evolution of micro-structure in unsaturated soil is not clear. For this reason, the capillary method is proposed to simulate compression test of unsaturated soil for analyzing soil-water interaction and evolution of pore spaces. In this research, an ideal micro-structure soil model of 540 μm×400 μm is established according to the shape and size of skeleton particles of loess. The capillary method is used to calculate the capillary water distribution and capillary force under different water content(5%, 10%, 18%), and the force then acts on the wetting surface among particles. The loading is applied to the soil sample. The compression test of unsaturated soil is simulated in this research. The simulation results show that the characteristics of compression curve are in good agreement with the experiment data, indicating that the numerical test can reflect the unsaturated soil deformation behavior under the condition of compress. Moreover, the saturation increases and matric suction decreases with the compression of the soil; the saturation increases most at high water content; the matric suction decreases least at middle water content; the deformation pattern is related with the moisture, namely, the pores are mainly shrunk at low water content while mainly disintegrated at high water content. The simulation results are a very useful supplement to laboratory test to explore the deformation mechanism of unsaturated soil.
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References
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LI Qiang, LI Tonglu, LI Hua, SHEN Wei, LI Ping, ZHANG Changliang. Numerical analysis of evolution of the unsaturated soil micro-structure with capillary action during compression[J]. Hydrogeology & Engineering Geology, 2022, 49(4): 135-143. doi: 10.16030/j.cnki.issn.1000-3665.202110045
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Figure 1.
Calculation of the capillary force on the single particle
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Figure 2.
Capillary water in the double-disk model at different water content
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Figure 3.
Capillary pressure calculated with theory and simulation
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Figure 4.
Particle size distribution curve
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Figure 5.
Unsaturated soil ideal model (a) and the initial distribution of capillary water under different water content (b—d)
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Figure 6.
Flow chart of simulation for the unsaturated soil compression test
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Figure 7.
Simulated compression curves
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Figure 8.
Variation of saturation and matric suction during compression
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Figure 9.
Model pore distribution at the end of compression under different water content
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Figure 10.
Main forms of pore deformation under different water content