Microscopic fabric characteristics of typical red soft rock in Badong Formation under uniaxial compression test

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 An-ti-corrosion Engineering Co. Ltd., Langfang 065000, China

Abstract

Red silty mudstone and argillaceous siltstone are the representatives of special rock and soil in Badong Formation, are easy to disintegrate when encountering water. According to the uniaxial compression test of rock samples, a numerical model of medium and soft rock uniaxial compression test was established based on PFC_2D program. With the characteristics of stress-strain curve, subsection quantitative parameter calibration method was used to calibrate the microscopic parameters of soft rock samples. The adjustment method and the ratio of tangential bond strength(σ_c/τ_c) control specimen under uniaxial compression failure mode. The uniaxial compression test of silty mudstone and argillaceous siltstone with different weathering degree under saturated and natural state was simulated. The distribution and evolution of meso-fabric parameters such as normal contact force, tangential contact force, coordination number and porosity were analyzed. The results show that the numerical method can well simulate the uniaxial compression test process of medium hard rock and soft rock. Except for medium weathered silty mudstone, weathering degree and water immersion condition can only affect the size of the contact force of sample particles in the statistical angle range, but cannot affect the distribution form. At the same time, weathering degree and water immersion condition prolonged the loading time of significantly decreased coordination number, which decreased with the increase of the number of cracks. Flooding condition and weathering degree have great influence on the porosity evolution of argillaceous siltstone. The degree of weathering has a great influence on the porosity evolution of silty mudstone, but the condition of flooding has little influence.

Keywords

Badong Formation, silty mudstone, argillaceous siltstone, discrete element, bond strength, coordination number

DOI

10.3969/j.issn.1001-1986.2019.06.017

Recommended Citation

XIAO Zunqun, WANG Xin, TANG Dongsang, et al. (2019) "Microscopic fabric characteristics of typical red soft rock in Badong Formation under uniaxial compression test," Coal Geology & Exploration: Vol. 47: Iss. 6, Article 18.
DOI: 10.3969/j.issn.1001-1986.2019.06.017
Available at: https://cge.researchcommons.org/journal/vol47/iss6/18

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