scholarly journals A novel approach to structural anisotropy classification for jointed rock masses using theoretical rock quality designation formulation adjusted to joint spacing

2021 ◽  
Author(s):  
Harun Sonmez ◽  
Murat Ercanoglu ◽  
Gulseren Dagdelenler
Keyword(s):  
Jointed Rock ◽  
Rock Masses ◽  
Rock Quality Designation ◽  
Structural Anisotropy ◽  
Joint Spacing ◽  
Jointed Rock Masses ◽  
Rock Quality ◽  
Novel Approach

scholarly journals Determination of representative elementary volume (REV) for jointed rock masses exhibiting scale-dependent behavior: A numerical investigation

2021 ◽  
Author(s):  
Mehmet Sari
Keyword(s):  
Jointed Rock ◽  
Representative Elementary Volume ◽  
Elementary Volume ◽  
Rock Masses ◽  
Continuum Approach ◽  
Joint Spacing ◽  
Jointed Rock Masses ◽  
Equivalent Continuum ◽  
Equivalent Continuum Approach

Abstract Representative elementary volume (REV) is defined as the usual size of a rock mass structure beyond which its mechanical properties are homogenous and isotropic, and its behavior can be modeled using the equivalent continuum approach. Determination of REV is a complex problem in rock engineering due to its definition ambiguity and application area. This study is one of the first attempts to define a REV for jointed rock masses using the equivalent continuum approach. It is aimed to numerically search a ratio between the characteristic size of an engineering structure and pre-existing joint spacing, which are the two most important contributing elements in assessing REV. For this purpose, four hypothetical engineering cases were investigated using the RS2 (Phase2 v. 9.0) finite element (FE) analysis program. An underground circular opening with a constant diameter, an open-pit mine with varying bench heights, a single bench with a constant height, and an underground powerhouse cavern with a known dimension were executed for possible changes in the safety factor and total displacement measurements under several joint spacing values. Different cut-off REVs were calculated for FE models depending on the type of excavation and measurement method. An average REV size of 19.0, ranging between a minimum of 2 for tunnels and a maximum of 48 for slopes, was found in numerical analysis. The calculated sizes of REV were significantly larger than the range of values (5 to 10) commonly reported in the relevant geotechnical literature.

scholarly journals Determination of representative elementary volume (REV) for jointed rock masses exhibiting scale-dependent behavior: a numerical investigation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mehmet Sari
Keyword(s):  
Jointed Rock ◽  
Representative Elementary Volume ◽  
Elementary Volume ◽  
Rock Masses ◽  
Continuum Approach ◽  
Joint Spacing ◽  
Jointed Rock Masses ◽  
Equivalent Continuum ◽  
Equivalent Continuum Approach

AbstractRepresentative elementary volume (REV) is defined as the usual size of a rock mass structure beyond which its mechanical properties are homogenous and isotropic, and its behavior can be modeled using the equivalent continuum approach. Determination of REV is a complex problem in rock engineering due to its definition ambiguity and application area. This study is one of the first attempts to define a REV for jointed rock masses using the equivalent continuum approach. It is aimed to numerically search a ratio between the characteristic size of an engineering structure and pre-existing joint spacing, which are the two most important contributing elements in assessing REV. For this purpose, four hypothetical engineering cases were investigated using the RS2 (Phase2 v. 9.0) finite element (FE) analysis program. An underground circular opening with a constant diameter, an open-pit mine with varying bench heights, a single bench with a constant height, and an underground powerhouse cavern with a known dimension were executed for possible changes in the safety factor and total displacement measurements under several joint spacing values. Different cut-off REVs were calculated for FE models depending on the type of excavation and measurement method. An average REV size of 19.0, ranging between a minimum of 2 for tunnels and a maximum of 48 for slopes, was found in numerical analysis. The calculated sizes of REV were significantly larger than the range of values (5 to 10) commonly reported in the relevant geotechnical literature.

scholarly journals Mechanical and failure characteristics of rock-like material with multiple crossed joint sets under uniaxial compression

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770871 ◽  
Author(s):  
Jiaming Liu ◽  
Shaorui Sun ◽  
Ling Yue ◽  
Jihong Wei ◽  
Jimin Wu
Keyword(s):  
Compressive Strength ◽  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Unconfined Compressive Strength ◽  
Failure Modes ◽  
Young's Modulus ◽  
Jointed Rock ◽  
Rock Masses ◽  
Joint Spacing ◽  
Jointed Rock Masses

The strength and deformation of rock masses transected by persistent joints are controlled by the fracture network. In this work, bonded particle model modeled by particle flow code in three dimensions was used to study the effect of geometry parameters on the strength and behavior of jointed rock masses under uniaxial compression. The effect of the number of crossed joint sets, joint orientation, and joint spacing on the uniaxial compressive strength was investigated, and this article presents the results of the numerical simulations. Rigorous validation process had done before the numerical experiments. Four types of blocks (Series A, B, C, and D) with different numbers of joint sets were considered in this article. Then, a sensitivity study is undertaken to investigate the effects of joint set numbers and joint geometry configuration on the failure mode, unconfined compressive strength, and Young’s modulus of jointed rock mass. The interaction among the crossed joint sets was found to have marked effects on the mechanical properties and failure modes. A study about the effects of joint spacing on the failure modes, unconfined compressive strength, and Young’s modulus was also conducted. Joint spacing was found to have no significant effect on the failure modes of jointed rock masses in a certain range. It is also shown that the range and variance of unconfined compressive strength are affected principally by joint set numbers and decreased slightly with the decrease in joint spacing. The effect of crossed joint sets on the stress field was carried out. Stress concentration was found to be the reason for relatively lower strength of blocks with crossed joint sets compared to the block with the same weakest single joint set. The result in this article is of great help to reveal the mechanism of damage and fracture of jointed rocks under uniaxial compression.

Sign in / Sign up

Export Citation Format

Share Document