Scale effects in the determination of mechanical properties of jointed rock masses

1993 ◽  
Vol 30 (5) ◽  
pp. 276
Keyword(s):  
Mechanical Properties ◽  
Scale Effects ◽  
Jointed Rock ◽  
Rock Masses ◽  
Jointed Rock Masses

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 Analysis of Changes in the Micromorphology of Sandstone Joint Surface under Dry-Wet Cycling

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jingcheng Fang ◽  
Huafeng Deng ◽  
Yu Qi ◽  
Yao Xiao ◽  
Hengbin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Angle ◽  
Jointed Rock ◽  
Joint Surface ◽  
Roughness Coefficient ◽  
Rock Masses ◽  
Jointed Rock Masses ◽  
Bank Slope ◽  
Steep Decrease ◽  
The Face

Changes in the micromorphology of joint surface under dry-wet cycling have a direct effect on the mechanical properties of the jointed rock masses, which in turn affects the deformation stability of the bank slope of a reservoir. In this study, we design and carry out a test that aims to quantity the effects of repeated rise and fall of a reservoir on the properties of a jointed rock masses. The results are as follows: first, the roughness, local gradient, and undulation of the joint surface gradually decreased under repeated dry-wet cycling. In addition, the height parameters and texture parameters showed a steep decrease followed by a slow decline. The deterioration was particularly obvious over the first 5 dry-wet cycles. Second, the roughness coefficient of the joint surface, the compressive strength of the face wall, and the basic friction angle were gradually reduced under dry-wet cycling. The shear strength of the jointed rock masses (obtained both quantitatively and experimentally) showed a deteriorating trend controlled by the deterioration of the micromorphology, the strength of the face wall, and the frictional properties of the joint surface. Finally, the dry-wet cycling process determined trends of changes in the microstructure parameters and mechanical properties of the joint surface. Our research results provide a good basis for the analysis of the deterioration and failure of rock masses within the hydrofluctuation belt of a bank slope.

Determination of structural domain boundaries in jointed rock masses: An example from the Songta dam site, China

2014 ◽  
Vol 69 ◽  
pp. 179-188 ◽  
Author(s):  
Yanyan Li ◽  
Qing Wang ◽  
Jianping Chen ◽  
Lili Han ◽  
Wen Zhang ◽  
...  
Keyword(s):  
Jointed Rock ◽  
Structural Domain ◽  
Rock Masses ◽  
Jointed Rock Masses ◽  
Domain Boundaries ◽  
Dam Site

Experimental study on the mechanical properties of simulated columnar jointed rock masses

2014 ◽  
Vol 12 (1) ◽  
pp. 80-89 ◽  
Author(s):  
Wei-min Xiao ◽  
Rong-gui Deng ◽  
Zhi-bin Zhong ◽  
Xiao-min Fu ◽  
Cong-yan Wang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Jointed Rock ◽  
Rock Masses ◽  
Jointed Rock Masses

A damage mechanical model applied to analysis of mechanical properties of jointed rock masses

2019 ◽  
Vol 84 ◽  
pp. 113-128 ◽  
Author(s):  
Wendong Yang ◽  
Qianbing Zhang ◽  
P.G. Ranjith ◽  
Rangang Yu ◽  
Guangyu Luo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Model ◽  
Jointed Rock ◽  
Rock Masses ◽  
Jointed Rock Masses

Crack Propagation of Jointed Rock and Application

2011 ◽  
Vol 117-119 ◽  
pp. 476-479
Author(s):  
Jing Wang ◽  
Wei Shen Zhu ◽  
Hai Ping Ma
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Failure Process ◽  
Jointed Rock ◽  
Rock Masses ◽  
Stress Strain ◽  
Jointed Rock Masses

Brittle media, such as rock mass, usually contain a great number of joints or cracks, which lead to varying mechanical properties and failure behaviors of different rock masses. In this paper, the DDARF method is adopted to simulate the crack initiation, propagation, coalescence and failure process in rock masses prefabricated with the different crack number and spacing under loading. The corresponding stress-strain curves and strength envelope are obtained. The parameters are applied in a case study. The differences in the failure behaviors of the intact and jointed rock masses after cavern excavation are analyzed and compared.

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