Random Meso-structure Model Generation and Numerical Biaxial Test of Waste-Fly Ash Backfill Materials

 

Zhan Liu

State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China;e-mail: liuzhan001st@gmail.com

Jixiong Zhang

School of Mines, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China

Nan Zhou

School of Mines, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China

 

 ABSTRACT

Mechanical properties of waste-fly ash backfill materials were researched with relatively new methods in this paper. We firstly developed a random meso-structure model generation program RMMG with MATLAB based on computational geometry algorithms, in the program parameters such as model sizes, waste content and waste granular size gradation, etc. can be controlled. Then we carried out a series of numerical biaxial tests under different confining stress and waste contents, by using particle flow code PFC2d combined with random meso-structure models generated by RMMG. The meso-structure model generating results show the effectiveness of RMMG, and the testing results indicate that the sample's elastic modulus, peak deviatoric stress and cohesion positively correlate to waste content, but the waste content doesn't affect sample's frictional angle. As waste content increases, faster and larger dilation can be observed during test. The results also prove high feasibility of using numerical biaxial test based on RMMG program and PFC2d to research the mechanical properties of waste-fly ash backfill materials.

Keywords: Backfill materials; random meso-structure model; PFC; numerical simulation.

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