An investigation on the correlation between the joint roughness coefficient (JRC) and joint roughness parameters

Abolfazli, Milad; Fahimifar, Ahmad

doi:10.1016/j.conbuildmat.2020.120415

Cited by 36 publications

(17 citation statements)

References 31 publications

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“…Tse and Cruden 32 proposed a regression formula for calculating joint roughness coefficient ( JRC ) values based on the analysis of the geometric characteristics of standard joint profile. Currently, this method is widely applied to the characterization of fracture face morphology 33–36

J R C = 32.2 + 32.47 lg Z_{2}

Z_{2} = \frac{1}{L} \int_{x = 0}^{L} {(\frac{dz}{dx})}^{2} = {(][, \frac{1}{M {(Δ x)}^{2}} \sum_{i = 1}^{M} {(y_{i + 1} y_{i})}^{2})}^{\frac{1}{2}}

where, L is the total length of the profile, mm; JRC is the joint roughness coefficient; Z 2 is the RMS of slope; Δ x is the sampling spacing along the x ‐direction, mm; y i +1 and y i are the elevations of two successive points over the length of the profile, respectively, mm; M is the total number of sampling intervals.…”

Section: Resultsmentioning

confidence: 99%

Experimental study on the shear‐slip characteristics of natural fractures in shale reservoirs

Shi

Chen

Gong

et al. 2022

Energy Science & Engineering

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Large-scale hydraulic fracturing is an essential technical method to achieve effective shale oil and gas development. 1 The complex interaction mechanism between HF and NF needs to be considered in the hydraulic fracturing of shale reservoirs. However, there are a large number of NF, faults, and bedding planes developed in the shale, and the presence of these surfaces of discontinuity significantly affects the geometry of the HF. [2][3][4][5][6][7] At the same time, the injection of high-pressure fluids and the propagation of HF may cause a shear slip in NF in the reservoir that are in a critical stress state. [8][9][10][11][12][13] Therefore, the study of the relationship between hydraulic and natural fracture

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J R C = 32.2 + 32.47 lg Z_{2}

Z_{2} = \frac{1}{L} \int_{x = 0}^{L} {(\frac{dz}{dx})}^{2} = {(][, \frac{1}{M {(Δ x)}^{2}} \sum_{i = 1}^{M} {(y_{i + 1} y_{i})}^{2})}^{\frac{1}{2}}

Section: Resultsmentioning

confidence: 99%

Experimental study on the shear‐slip characteristics of natural fractures in shale reservoirs

Shi

Chen

Gong

et al. 2022

Energy Science & Engineering

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“…Formula Ref. JRC = 411(R P − 1) JRC = 65.9(R P − 1) 0.302 − 9.65 [21] [22] [23] [25] [27] [28] [29] JRC = −106.67(θ p + ) −0.363 + 55.34 [30] Z…”

Section: Parametermentioning

confidence: 99%

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

Yuan

Luo

et al. 2021

Applied Sciences

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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.

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“…Grouting has been one of the prominent solutions of engineers for dealing with a variety of geotechnical dilemmas, from the improvement of strength, density and porosity characteristics in loose soils, to filling the joints and cracks existing in rock and concrete [ 1 , 2 , 3 , 4 , 5 , 6 ]. The injection has proven its practicality and effectiveness when other approaches fail to function as a permanent and stable remedy for such problems [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Investigating the Effects of Cement and Polymer Grouting on the Shear Behavior of Rock Joints

et al. 2022

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This study carried out a comparison between cement grouting and chemical grouting, using epoxy and polyurethane, with respect to their effects on the shear behavior of joints. Joint replicas, with three different grades of surface roughness, were molded and grouted by means of cement and epoxy grouts of various mixtures. To investigate their shear behavior, samples were subjected to direct shear tests under constant normal load (CNL) condition. According to the results obtained, grouting improves the overall shear strength of the rock joints. All the grouted samples yielded higher maximum and residual shear strength in comparison with the non-grouted joint. Grouting resulted in an improvement in the cohesion of all the samples. However, a fall in friction angle by 5.26° in the sample with JRC of nine was observed, yet it was reduced by 2.36° and 3.26° for joints with JRC of 14 and 19, respectively. Cement grouts were found to have a more brittle behavior, whereas the chemical grouts were more ductile. Higher amounts of cement used in the grout mixture do not provide as much cohesion and only increase the brittleness of the grout. As a result of being more brittle, cement grout breaks into small pieces and joint planes are in better contact during shearing; consequently, there would be less of a fall in friction angle as opposed to epoxy grout whose ductile characteristic prevents grout chipping; therefore, joint planes are not in contact and a greater fall in the friction angle occurs. There was no noticeable change in the cohesion of the larger grouted joints. However, the friction angle of both natural and grouted joints increased in the larger joint. This can be related to the distribution of random peaks and valleys on the joint surface, which increases with the joint size.

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An investigation on the correlation between the joint roughness coefficient (JRC) and joint roughness parameters

Cited by 36 publications

References 31 publications

Experimental study on the shear‐slip characteristics of natural fractures in shale reservoirs

Experimental study on the shear‐slip characteristics of natural fractures in shale reservoirs

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

Investigating the Effects of Cement and Polymer Grouting on the Shear Behavior of Rock Joints

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