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Geomechanics and Engineering
  Volume 13, Number 6, December 2017, pages 977-995
DOI: http://dx.doi.org/10.12989/gae.2017.13.6.977
 


The investigation of rock cutting simulation based on discrete element method
Xiaohua Zhu, Weiji Liu and Yanxin Lv

 
Abstract
    It is well accepted that rock failure mechanism influence the cutting efficiency and determination of optimum cutting parameters. In this paper, an attempt was made to research the factors that affect the failure mechanism based on discrete element method (DEM). The influences of cutting depth, hydrostatic pressure, cutting velocity, back rake angle and joint set on failure mechanism in rock-cutting are researched by PFC2D. The results show that: the ductile failure occurs at shallow cutting depths, the brittle failure occurs as the depth of cut increases beyond a threshold value. The mean cutting forces have a linear related to the cutting depth if the cutting action is dominated by the ductile mode, however, the mean cutting forces are deviate from the linear relationship while the cutting action is dominated by the brittle mode. The failure mechanism changes from brittle mode with larger chips under atmospheric conditions, to ductile mode with crushed chips under hydrostatic conditions. As the cutting velocity increases, a grow number of micro-cracks are initiated around the cutter and the volume of the chipped fragmentation is decreasing correspondingly. The crack initiates and propagates parallel to the free surface with a smaller rake angle, but with the rake angle increases, the direction of crack initiation and propagation is changed to towards the intact rock. The existence of joint set have significant influence on crack initiation and propagation, it makes the crack prone to propagate along the joint.
 
Key Words
    discrete element method; rock cutting; failure mechanism; fracture propagation; hydrostatic pressure
 
Address
Xiaohua Zhu and Weiji Liu: School of Mechatronic Engineering, Southwest Petroleum University, Chengdu 610500, China

Yanxin Lv: 1.) School of Mechatronic Engineering, Southwest Petroleum University, Chengdu 610500, China

2.) State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
 

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