Numerical Determination of RVE for Heterogeneous Geomaterials Based on Digital Image Processing Technology

Abstract

Representative volume element (RVE) is an important parameter in numerical tests of mechanical properties of heterogeneous geomaterials. For this study, a digital image processing (DIP) technology was proposed for estimating the RVE of heterogeneous geomaterials. A color image of soil and rock mixture (SRM) with size of 400 × 400 mm 2 taken from a large landslide was used to illustrate the determination procedure of the SRM. Six sample sizes ranging from 40 × 40 mm 2 to 240 × 240 mm 2 were investigated, and twelve random samples were taken from the binarized image for each sample size. A connected-component labeling algorithm was introduced to identify the microstructure. After establishing the numerical finite difference models of the samples, a set of numerical triaxial tests under different confining pressures were carried out. Results show that the size of SRM sample affects the estimation of the mechanical properties, including compressive strength, cohesion, and internal friction angle. The larger the size of the samples, the less variability of the estimated mechanical properties. The coefficient of variation (CV) was applied to measure the variability of mechanical properties, and the RVE of the SRM was determined easily with a predefined acceptance threshold of the CV. The results show that a DIP-based modeling method is an effective method got the RVE determination of heterogeneous geomaterials.

Uncertainty of volume fraction in bimrock using the scan-line method and its application in the estimation of deformability parameters

“…The common practice is to employ either 1D or 2D measurements, or both (Sonmez et al 2004). Many investigators resolved to use aerial fractions of outcrops (2D surfaces), augmented with field and laboratory tests to obtain the geometric information of bimrock/bimsoil from outcrops (Medley 1994;Xu et al 2008Xu et al , 2011Coli et al 2012;Kahraman et al 2015;Ymeti et al 2017;Liu et al 2018;Meng et al 2018;Yang et al 2019). However, it is not always possible to obtain areal fraction of blocks through image analysis if the blocks are dyed by matrix or the chromatism between blocks and matrix is small.…”