Modeling of joint propagation in fractured rock slopes (Case study: Final Slope of Tectonic block IV-2 of Choghart mine)

Document Type : Original Article

Authors

1    MSc. Graduate Student of Rock mechanics, Department of Mining & Matallurgical Engineering, Yazd University, Iran

2    Associate Professor., Department of Mining & Matallurgical Engineering & Mining Technologies Research Center, Yazd University, Iran * ayarahmadi@yazd.ac.ir

3 Associate Professor., Department of Mining & Matallurgical Engineering

Abstract

In nature, rocks contain non persistent joints and in rock slope stability analyses it is assumed that discontinuity is persistent, while stress intensity is centralized attips of non-persistent joints and this stress intensity affects the size and orientation of  joint growth in rock and  also stability of structures created in it such as rock slope. Fracture mechanics is a science that discusses the probability of joints growth and also fracture propagation path. The development of this science provides the possibility of using actual non persistent joints modeling in rock slope stability as well as controlling mechanical behavior of discontinuities especially in crack tips. By creating rock slopes and changing the matrix of regional stress, intensity of stress occurs in joints tips. If this stress overcomes strength parameters of the joint, it will grow and joint propagation will result. One type of failure that occurs in rocky environments due to crack propagation is toppling whose analysis is one of the most difficult problems in aeromechanics. The aim of this study is to model joint propagation by using the principles of rock fracture mechanics, growth and publication ofnon -persistent and random joints in rock slope with potential of toppling failure. An acceptable numerical method for joint propagation modeling that is boundary element method as displacement discontinuity method (DDM) was selected. As a case study tectonic block IV-2 of Choghart open pit mine was selected and3D geometrical model by random disk method by 3DGMMathematica program was simulated and also 2D cross section was prepared. The amount and direction of joint propagation were calculated by applying boundary conditions, in-situ stresses and stiffness matrix. The mechanical model was created according to geomechanical characteristics reported in stability analysis of this wall. Length of linear elements in joints was considered 3m and propagation step applied was 0.2 over the joint length and the model was run typically in four stages of crack growth. Obtained geometrical model contains early and propagation joints can be used in softwares  that  geometrical model of joints is essential I analysis but the propagation of joint is not available. So the program code can be used as a complementary method for analysis method as key-groups method and distinct element method (UDEC) to analyze the jointed rock mass

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References

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Scientific Quarterly Journal of Iranian Association of Engineering Geology
Volume 10, Number 1 & 2
September 2017
Pages 1-13

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History

  • Receive Date: 27 September 2015
  • Revise Date: 19 March 2017
  • Accept Date: 22 September 2018

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