The microscopic fabric characteristics of biaxial compression test of typical argillaceous siltstone in Badong Formation

Authors

XIAO Zunqun, Xingfa School of Mining Engineering, Wuhan Institute of Technology, Wuhan 430000, China;School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan 430000, China
WANG Xin, Xingfa School of Mining Engineering, Wuhan Institute of Technology, Wuhan 430000, ChinaFollow
TANG Dongsang, School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan 430000, China
DONG Qiongying, Xingfa School of Mining Engineering, Wuhan Institute of Technology, Wuhan 430000, China
JIANG Yinan, Xingfa School of Mining Engineering, Wuhan Institute of Technology, Wuhan 430000, China
YANG Kai, School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan 430000, China
CAO Tongtong, Xingfa School of Mining Engineering, Wuhan Institute of Technology, Wuhan 430000, China
DENG Zhen, China Petroleum Pipeline Anti-corrosion Engineering Co. Ltd., Langfang 065000, China

Abstract

Based on the indoor biaxial compression test of argillaceous siltstone, a numerical model of PFC2D particle flow was established. The model considered the particle shape of the argillaceous siltstone samples. Five typical particle shapes were selected according to the scanning electron microscope, and the circular particles were selected. A stable numerical sample of a given porosity was randomly generated together. The parallel bond contact model was selected between the particles, and the elastic modulus, Poisson’s ratio and peak stress were selected to calibrate the meso-parameters of the saturated and natural argillaceous siltstone samples under different confining pressures, and then the biaxial compression test was carried out. The simulation analysis of the distribution characteristics and evolution of the meso-structure parameters such as particle normal contact force, tangential contact force, coordination number and porosity during the biaxial compression test were analyzed. The test results show that the meso-parameter calibration of the biaxial compression test can ignore the influence of the shear strength indicators c and . Before and after the failure, the normal contact force and the tangential contact force existed between the particles in the statistical range of the sample in all directions. The presence of confining pressure affects the initial coordination number of the sample, the porosity and the stable coordination number and porosity after the sample is destroyed, and has little effect on the rate of change of coordination number and porosity. The evolution of the spatial porosity of the sample reflects the change of the internal structure when the sample is destroyed to a certain extent, which can reflect the failure mode of the sample more intuitively

Keywords

biaxial compression test, microstructure, tangential contact force, normal contact force, coordination number, mesoscopic parameters, evolution

DOI

10.3969/j.issn.1001-1986.2020.02.025

Recommended Citation

XIAO Zunqun, WANG Xin, TANG Dongsang, et al. (2020) "The microscopic fabric characteristics of biaxial compression test of typical argillaceous siltstone in Badong Formation," Coal Geology & Exploration: Vol. 48: Iss. 2, Article 26.
DOI: 10.3969/j.issn.1001-1986.2020.02.025
Available at: https://cge.researchcommons.org/journal/vol48/iss2/26

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