[Underground Engineering]
Zhou X, Xiao N. Analysis of fracture properties of three-dimensional reconstructed rock model using hierarchical-fractal annealing algorithm. Engineering Geology. 2019;256:39-56.
Keywords: Three-dimensional reconstruction, Porous structure, Sandstone, Fractal function, Local histogram function, Hierarchical annealing
Abstract:
IThe irregularity and multi-scale features are the most important and intrinsic characteristics for rocks, which are caused by the variety of microstructures. In this paper, a novel reconstruction method is proposed to reconstruct a porous rock model based on limited morphological information. The configurations of the pore structures in Xingluokeng sandstone are investigated by the X-ray Micro-CT observation. Then, a triaxial compressive test is conducted to obtain necessary mechanical properties. Compared with the traditional reconstruction method, the novel reconstruction method adopts the hierarchical annealing algorithm and gains considerable computational efficiency. Moreover, considering the irregularity and multi-scale features of rocks, the fractal function variables over time, and the local histogram function are introduced to describe these characteristics. The finite element-smooth particle dynamic coupling method is employed to simulate the mechanical responses and fractures of the reconstructed model under compression. The topological verification and comparison between the simulation results and experimental data show that the novel reconstruction method can predict the large scale properties of rocks with limited experimental results, which indicate the novel reconstruction method has a important application in the prediction of geological conditions for engineering project.
Resource：https://doi.org/10.1016/j.enggeo.2019.04.017
[Underground Engineering]
Zhao Z, Zhou X. Digital measurement of 2D and 3D cracks in sandstones through improved pseudo color image enhancement and 3D reconstruction method. International Journal for Numerical and Analytical Methods in Geomechanics. 2019;43(16):2565-84.
Keywords: digital damage ratio, X‐ray CT images, 3D reconstruction, improved pseudo color image enhancement algorithm, triaxial compression test
Abstract:
An integrated approach of improved pseudo color image enhancement (IPCE) method and three‐dimensional (3D) reconstruction technology is proposed. The evolution characteristics of two‐dimensional (2D) and 3D spatial cracks in X‐ray computed tomography (CT) images of sandstones subjected to triaxial compression with confining pressure of 10, 20, and 30 MPa are investigated. The equations of crack width, length, and dip angle are established based on the proposed digital damage ratio. Based on the pseudo color images, point cloud maps with roughness and spatial images of cracks are investigated. The numerical results show that this proposed method is effective to study and understand the fracturing properties of rocks.
Resource：https://doi.org/10.1002/nag.2993
