Supported by the National Natural Science Foundation of China (No. 42002257), the Natural Science Foundation of Shandong Province, China (No. ZR2020QD123), and the Doctor Foundation of University of Jinan, China (No. XBS1911)
【Objective】 The study of the groundwater seepage process in saturated soil media is of great importance in many fields, and the differences in the pore-scale structure of soil media have a significant effect on the properties of groundwater seepage. Soil grains cementation degree is one of the basic properties of soil media, but there are few studies on the effect of pore-scale structure differences of soil media with different cementation degrees on the properties of the groundwater seepage process. 【Method】 In this paper, related research is carried out based on pore-scale simulation. Soil media with different cementation degrees are constructed based on the global rearrangement algorithm, and the finite element software package is adopted to simulate the flow fields. 【Result】 The results showed that as the percentage of cemented soil particles Pc increased from 0 to 60.20%, the variation function of the flow field increased by 70.15% (from 1.233 to 2.098). Namely, the spatial heterogeneity of the flow velocity was significantly increased with increasing cementation degree. In addition, the probability density distribution of the flow velocity along the main groundwater flow direction and perpendicular to the main flow direction were increasingly divergent. The area where the flow velocity was close to the mean velocity decreased, and the stagnant regions and the preferential flow areas extend significantly at the same time. When Pc increased from 0 to 60.20%, the proportion of stagnant regions in the groundwater rose 23 times (from 2.06% to 48.31%), while the proportion of dominant flow areas increased nearly 9 times (from 0.27% to 2.41%). Also, when the average velocity of fluid was different, the above change trends of the seepage characteristics with rising cementation degrees remained the same. 【Conclusion】 These findings indicate that the cementation degree of soil particles has a significant effect on the characteristics of the groundwater flow field in saturated soil media. Besides, this paper found that the pore-scale structure differences of soil media with different cementation degrees are the internal reason for the above changes in groundwater seepage process characteristics. The dead-end pore structure formed by cementation, the irregular boundary of the cementation group, and the areas with poor connectivity upstream but connected to the flow area downstream often lead to the appearance of stagnant flow regions. With the increase of the stagnant regions, the fluid flows into the well-connected pores and flows rapidly along these pores. As a result, the dominant flow areas also increased with the rising cementation degree and even formed continuous dominant seepage channels. Under the influence of the simultaneous increase of stagnant regions and the dominant flow areas, the spatial heterogeneity of velocity was significantly enhanced.
HOU Yusong, XIN Hu, LIU Su, HU Xiaonong, SU Jingfang, WU Jichun, XING Liting. Effects of Pore-scale Structure of Saturated Soil with Different Cementation Degrees on Groundwater Seepage Characteristic[J]. Acta Pedologica Sinica,2024,61(2):398-407.Copy