EGU General Assembly 2020
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How representative is the conventional undisturbed soil core sample in terms of fllow properties?

Kirill Gerke and Marina Karsanina
Kirill Gerke and Marina Karsanina
  • Schmidt Institute of Physics of the Earth of Russian Academy of Sciences, Moscow, Russian Federation (

Classic soil physics relies heavily on the concept of representative elementary volume (REV), which is necessary to perform upscaling from the studied soil samples and parameterize continuum scale hydrological models (e.g., based on Richards equation). In this paper we explore the boundaries of the classic REV concept and conventional representativity studies that claim REV for a given physical property if its values converge to a steady value with increasing sample’s volume. We chose two conventional undisturbed soil samples from Ah and B horizons and performed pore-scale flow simulations based on their X-ray microtomography scans. The volumes of the simulation domains were 729 million of voxels with a physical volume within the order of magnitude of the whole soil core. Based on 3D pore geometry images and resulting flow velocity and pressure fields we performed REV analysis for saturated hydraulic conductivity and porosity. To further facilitate the REV analysis, we also evaluated the stationarity of pore structures by computing directional correlation functions for studied images. We concluded that neither of the studied samples can be considered to be representative due to its structural non-stationarity, which reflects on the behavior of Ksat values within the subcubes of different volume within the samples. In this contribution we extensively discuss the implications of such results. While it was possible to show that studied soil samples are not REVs for saturated hydraulic conductivity, we were unable to establish any relevant domain length scale. The latter may require tensorial flow property analysis with correct boundary conditions (Gerke et al., 2019), multi-scale soil structure imaging (Gerke et al., 2015; Karsanina et al., 2018; Karsanina and Gerke, 2018) and pore-scale simulations on fused multi-scale images (Miao et al., 2017; Gerke et al., 2018).

This work was supported by Russian Foundation for Basic Research grant 20-54-12030 ННИО_а and 18-34-20131 мол_а_вед.


Karsanina, M. V., Gerke, K. M., Skvortsova, E. B., Ivanov, A. L., & Mallants, D. (2018). Enhancing image resolution of soils by stochastic multiscale image fusion. Geoderma, 314, 138-145.

Gerke, K. M., Karsanina, M. V., & Mallants, D. (2015). Universal stochastic multiscale image fusion: an example application for shale rock. Scientific reports, 5, 15880.

Gerke, K. M., Vasilyev, R. V., Khirevich, S., Collins, D., Karsanina, M. V., Sizonenko, T. O., Korost D.V., Lamontagne S., & Mallants, D. (2018). Finite-difference method Stokes solver (FDMSS) for 3D pore geometries: Software development, validation and case studies. Computers & Geosciences, 114, 41-58

Karsanina, M. V., & Gerke, K. M. (2018). Hierarchical Optimization: Fast and Robust Multiscale Stochastic Reconstructions with Rescaled Correlation Functions. Physical Review Letters, 121(26), 265501.

Miao, X., Gerke, K. M., & Sizonenko, T. O. (2017). A new way to parameterize hydraulic conductances of pore elements: A step towards creating pore-networks without pore shape simplifications. Advances in Water Resources, 105, 162-172.

Gerke, K. M., Karsanina, M. V., & Katsman, R. (2019). Calculation of tensorial flow properties on pore level: Exploring the influence of boundary conditions on the permeability of three-dimensional stochastic reconstructions. Physical Review E, 100(5), 053312.

How to cite: Gerke, K. and Karsanina, M.: How representative is the conventional undisturbed soil core sample in terms of fllow properties?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10841,, 2020


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  • CC1: Comment on EGU2020-10841, Sarah Garré, 05 May 2020

    Dear Kirill and Marina,

    thanks for this great contribution. I've also been struggling with this since the beginning of my steps in soil physics and touched upon the topic a bit when studying stony soils. Apparently, even in 'normal' soils, classical measurements are not necessarily suited to parameterize models. What do you suggest then to move forward?

    • AC1: Reply to CC1, Kirill Gerke, 05 May 2020

      Thank you for your comment, Sarah! And for general interest in our work. Indeed, the topic is completely vague and everything about REV is taken for granted without any consideration. It seems that the concept of REV is not useful, or even harful to move our models forward.

      Well, to answer your question... We are not yet sure exactly, but our first steps would be to distinguish stationary zones (if they even exist) in soil. For this we would need to perform multu-scale imaging of soil structure. Next, we have to compute physical properties for such zones and then try to assemble them into larger soil volumes and see how it works.

      We currently lack good datasets for such work, morevoer, we also do not have methodologies, e.g., to extract such zones. We are working on some aspects of this and may report something may be next EGU. Hope we have addressed your question.