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Geomechanics and Engineering
  Volume 28, Number 2, January25 2022 , pages 117-133
DOI: https://doi.org/10.12989/gae.2022.28.2.117
 


2D numerical study of the mechanical behaviour of non-persistent jointed rock masses under uniaxial and biaxial compression tests
Mojtaba Rabiei Vaziri, Hossein Tavakoli and Mojtaba Bahaaddini

 
Abstract
    Determination of the mechanical behaviour of jointed rock masses has been a challenge for rock engineers for decades. This problem is more pronounced for non-persistent jointed rock masses due to complicated interaction of rock bridges on the overall behaviour. This paper aims to study the effect of a non-persistent joint set configuration on the mechanical behaviour of rock materials under both uniaxial and biaxial compression tests using a discrete element code. The numerical simulation of biaxial compressive strength of rock masses has been challenging in the past due to shortcomings of bonded particle models in reproducing the failure envelope of rock materials. This problem was resolved in this study by employing the flat-joint contact model. The validity of the numerical model was investigated through a comprehensive comparative study against physical uniaxial and biaxial compression experiments. Good agreement was found between numerical and experimental tests in terms of the recorded peak strength and the failure mode in both loading conditions. Studies on the effect of joint orientation on the failure mode showed that four zones of intact, transition to block rotation, block rotation and transition to intact failure occurs when the joint dip angle varies from 0◦ to 90◦. It was found that the applied confining stress can significantly alter the range of these zones. It was observed that the minimum strength occurs at the joint dip angle of around 45 degrees under different confining stresses. It was also found that the joint orientation can alter the post peak behaviour and the lowest brittleness was observed at the block rotation zone.
 
Key Words
    DEM; failure mode; flat-Joint model; mechanical behaviour; non-persistent jointed rock mass
 
Address
Mojtaba Rabiei Vaziri and Hossein Tavakoli: Department of Mining Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
Mojtaba Bahaaddini: Department of Mining Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran;
School of Minerals and Energy Resources Engineering, UNSW Sydney, Sydney, Australia
 

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