scholarly journals Quasi-static resonant column (QSRC) method for indirect assesment of natural weathered rock joint surface

2018 ◽  
Author(s):  
Z. Mohamed ◽  
M. M. Mohd-Nordin
Keyword(s):  
Rock Joint ◽  
Joint Surface ◽  
Resonant Column ◽  
Weathered Rock

scholarly journals Experimental Study on 3D Roughness and Shear Failure Mechanism of Rock Mass Discontinuity

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Jihong Wei ◽  
Yan Men ◽  
Shaorui Sun ◽  
Huilin Le ◽  
Feng Zhu
Keyword(s):  
Surface Topography ◽  
Physical Model ◽  
Residual Strength ◽  
Failure Modes ◽  
Rock Joint ◽  
Model Construction ◽  
Joint Surface ◽  
Shear Direction ◽  
Direct Shear ◽  
Normal Stresses

A set of systematic experimental methods, including 3D accuracy scanning and identification of discontinuous surface topography, physical model construction, and laboratory direct shear experiment under different directions and normal stresses, was proposed to research the influence of discontinuity roughness on strength and deformation of discontinuity. During physical model construction of discontinuity, three types of discontinuity and rough natural rock joint surface models were constructed and moulded. Meanwhile, many influence factors of discontinuity surface topography, such as asperity inclination angle (AIA), asperity height (AH), normal stress (NS), and shear direction (SD), were considered during the direct shear experiment. On the basis of the experimental results, it can be found that there were two types of failure modes under different loading conditions, which were named “failure by shearing through the asperities” and “failure by sliding over the asperities”. The obvious stress concentration phenomenon, climbing, and cutting effects appeared in the process of the direct shear experiment. In addition, the accurate identification of surface topography of natural rough rock joint surface was carried out using three-dimensional sensing system (3DSS) and self-programming software before and after the experiment. The subsamples with the same surface topography as the original samples were moulded using a self-developed instrument. Then, the mechanical behavior of the original samples and subsamples for the natural rough rock joint surface under different shear directions and normal stresses was studied. The results show that the shear displacement under different shear directions and normal stresses is very large before it reaches the failure state. And the residual strength of the original samples is higher than that of the subsamples. In addition, failure modes of the subsamples are main failure by shearing through the asperities due to the significant difference between peak shear strength and residual strength. The failure modes for parts of the original samples are failure by sliding over the asperities. The change ratio of area for the discontinuity after the experiment depends on surface topography, strength of heave on the surface of discontinuity, and particle size of minerals on the surface of discontinuity.

scholarly journals Scale Dependence of Waviness and Unevenness of Natural Rock Joints through Fractal Analysis

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Yingchun Li ◽  
Shengyue Sun ◽  
Hongwei Yang
Keyword(s):  
Surface Roughness ◽  
Rock Joint ◽  
Fractal Dimensions ◽  
Window Size ◽  
Scale Dependence ◽  
Rock Joints ◽  
Joint Surface ◽  
Triangular Prism ◽  
Natural Rock ◽  
Waviness And Unevenness

The scale dependence of surface roughness is critical in characterising the hydromechanical properties of field-scale rock joints but is still not well understood, particularly when different orders of roughness are considered. We experimentally reveal the scale dependence of two-order roughness, i.e., waviness and unevenness through fractal parameters using the triangular prism surface area method (TPM). The surfaces of three natural joints of granite with the same dimension of 1000 mm×1000 mm are digitised using a 3D laser scanner at three different measurement resolutions. Waviness and unevenness are quantitatively separated by considering the area variation of joint surface as grid size changes. The corresponding fractal dimensions of waviness and unevenness in sampling window sizes ranging from 100 mm×100 mm to 1000 mm×1000 mm at an interval of 100 mm×100 mm are determined. We find that both the fractal dimensions of waviness and unevenness vary as the window size increases. No obvious stationarity threshold has been found for the three rock joint samples, indicating the surface roughness of natural rock joints should be quantified at the scale of the rock mass in the field.

Analysis and Reconstruction of Rock Joint Surface Based on DCT Algorithm

2021 ◽  
pp. 923-933
Author(s):  
Lianheng Zhao ◽  
Dongliang Huang ◽  
Shuaihao Zhang ◽  
Xiang Wang ◽  
Yingbin Zhang ◽  
...  
Keyword(s):  
Rock Joint ◽  
Joint Surface

Quantitative Parameters for Rock Joint Surface Roughness

2000 ◽  
Vol 33 (4) ◽  
pp. 217-242 ◽  
Author(s):  
T. Belem ◽  
F. Homand-Etienne ◽  
M. Souley
Keyword(s):  
Surface Roughness ◽  
Rock Joint ◽  
Joint Surface ◽  
Quantitative Parameters

scholarly journals A New Characterization Method for Rock Joint Roughness Considering the Mechanical Contribution of Each Asperity Order

2021 ◽  
Vol 11 (15) ◽  
pp. 6734
Author(s):  
Zhouhao Yuan ◽  
Yicheng Ye ◽  
Binyu Luo ◽  
Yang Liu
Keyword(s):  
Rock Joint ◽  
Statistical Parameter ◽  
Ensemble Empirical Mode Decomposition ◽  
Joint Surface ◽  
Roughness Coefficient ◽  
Joint Roughness ◽  
Red Sandstone ◽  
Direct Shear Tests ◽  
Waviness And Unevenness ◽  
The Relationship

The morphology of the joint surface is multi-scale, and it can be divided into first-order asperity (waviness) and second-order asperity (unevenness). At present, the joint roughness characterization formula considers only the morphology contribution of waviness and unevenness components and does not fully consider their mechanical contribution. At same time, the relationship between the mechanical contribution and the morphology contribution is still unclear. Thus, the characterization formula considering the mechanical contribution of waviness and unevenness needs to be further studied. In this study, the standard joint roughness coefficient (JRC) profiles were first decomposed into waviness and unevenness. Then, three types of joint specimens with different asperity orders (flat, the standard JRC profile, and the profile containing only waviness) were prepared by the 3D engraving technique. Finally, direct shear tests were carried out on 39 sets of red sandstone joint specimens under three normal stresses. The mechanical contributions of waviness and unevenness were studied, the relationship between the mechanical contribution and the morphology contribution of waviness and unevenness was analyzed, and the characterization formula considering the mechanical contribution of waviness and unevenness was established. The results showed that the following: (1) the method combining the ensemble empirical mode decomposition (EEMD) and the critical decomposition level could be used to separate the waviness and unevenness from the joint surface; (2) the mechanical contribution of the waviness and unevenness decreased with the increase in normal stress; (3) the relationship between the mechanical contribution ratio and the statistical parameter ratio of the waviness and unevenness can be describe by power function; and (4) the roughness characterization formula considering the mechanical contribution and morphology contribution was established. This study will enhance the accurate evaluation of the roughness coefficient and shear strength of the joint specimen.

scholarly journals Generalized Models for Rock Joint Surface Shapes

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Shigui Du ◽  
Yunjin Hu ◽  
Xiaofei Hu
Keyword(s):  
Rock Joint ◽  
Statistical Analyses ◽  
Relative Amplitude ◽  
Joint Surface ◽  
Mechanical Effects ◽  
Field Investigations ◽  
Extensive Field ◽  
Study Results ◽  
Surface Profiles ◽  
Basic Features

Generalized models of joint surface shapes are the foundation for mechanism studies on the mechanical effects of rock joint surface shapes. Based on extensive field investigations of rock joint surface shapes, generalized models for three level shapes named macroscopic outline, surface undulating shape, and microcosmic roughness were established through statistical analyses of 20,078 rock joint surface profiles. The relative amplitude of profile curves was used as a borderline for the division of different level shapes. The study results show that the macroscopic outline has three basic features such as planar, arc-shaped, and stepped; the surface undulating shape has three basic features such as planar, undulating, and stepped; and the microcosmic roughness has two basic features such as smooth and rough.

scholarly journals Experimental Study on Relationship Between Mechanical, Seepage Characteristics and 3D Morphology Parameters of Marble Joint

2016 ◽  
Vol 10 (1) ◽  
pp. 513-523 ◽  
Author(s):  
Chenlin Wang ◽  
Baohua Guo ◽  
Long Wang
Keyword(s):  
Normal Stress ◽  
Linear Relation ◽  
Rock Joint ◽  
Laser Scanner ◽  
Coarse Grained ◽  
Joint Surface ◽  
3D Morphology ◽  
Hydraulic Aperture ◽  
Seepage Characteristics ◽  
Morphology Parameters

In order to investigate the influence of 3D morphology parameters of marble joint surface on its mechanical and seepage characteristics, artificial joints of coarse-grained marbles were scanned by Tianyuan OKIO-typed 3D laser scanner; and then, the professional software was used to obtain the 3D morphology parameters of marble joint surface. Tests of water flowing through a single joint were conducted under different normal stress and feeding water head by using self-developed radial flowing system, and the exponential function between flow rate per head and normal stress, the linear relation between equivalent hydraulic aperture and mechanical aperture, and the linear relation between joint closure and normal stress were obtained. The relationships between regression parameters in above three formulas and 3D morphology parameters of joint surface were also studied by fitting method. All in all, the results may provide a reference to understand the mechanical and seepage characteristics of rough rock joint.

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