Calculations on Roughness of Rock Fracture Based on Image Processing

2012 ◽  
Vol 256-259 ◽  
pp. 203-206
Author(s):  
Xiao Bo Yu ◽  
Yang Song Zhang ◽  
Ruo Yao Li
Keyword(s):  
Rock Fracture ◽  
Gansu Province ◽  
Rock Joints ◽  
Nuclear Waste Repository ◽  
Roughness Coefficient ◽  
Rock Fractures ◽  
High Radiation ◽  
Deformation Parameters ◽  
Strength And Deformation ◽  
The Relationship

Joint roughness coefficient (JRC) is an important factor in the evaluation of the shear strength and deformation parameters of rock joints. This paper presents a method for measuring JRC of rock fractures based on digital image progressing technique. Though preprocessing of the rock fracture image, the skeleton of the fracture was got, the rough degree were analyzed and quantized by geometric parameters of the skeleton. By establishing the relationship between JRC and the rough degree, JRC will be got though the rough degree. This method improves automation degree and accuracy comparing to the previous methods. Finally this method was used to get the JRC of rock fracture in Jijicao, Beishan, Gansu province, where may be the high-radiation nuclear waste repository.

scholarly journals Correlation between the Joint Roughness Coefficient and Rock Joint Statistical Parameters at Different Sampling Intervals

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Man Huang ◽  
Cia-chu Xia ◽  
Peng Sha ◽  
Cheng-rong Ma ◽  
Shi-gui Du
Keyword(s):  
General Formula ◽  
Rock Joint ◽  
Statistical Parameter ◽  
Rock Joints ◽  
Estimation Accuracy ◽  
Roughness Coefficient ◽  
Joint Roughness Coefficient ◽  
Joint Roughness ◽  
The Relationship ◽  
Fitting Parameters

Joint roughness coefficient (JRC) is a major factor that affects the mechanical properties of rock joints. Statistical methods that are used to calculate the JRC increasingly depend on a sampling interval (Δx). The variation rules of fitting parameters a, b, and b/a at different Δx values were analyzed on the basis of the relationship between the JRC and statistical parameter Z2. The relationship between the fitting parameters a and b was deduced in accordance with the ten standard profiles proposed by Barton. Empirical formulas for the JRC, Z2, and Δx were also established. The estimation accuracy of the JRC was the highest in the analysis of Δx values within 0.1–5.0 mm. JRC tests were conducted through inverse value comparative analysis. Results showed that the outcome calculated using the general formula and the JRC inverse values demonstrate improved agreement and verify the rationality of the general formula. The proposed formula can perform rapid and simple JRC calculation within the Δx range of 0.1–5.0 mm using Z2, thereby indicating favorable application prospects.

scholarly journals Photogrammetric Prediction of Rock Fracture Properties and Validation with Metric Shear Tests

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 293
Author(s):  
Lauri Uotinen ◽  
Masoud Torkan ◽  
Alireza Baghbanan ◽  
Enrique Caballero Hernández ◽  
Mikael Rinne
Keyword(s):  
Shear Strength ◽  
Rock Fracture ◽  
Friction Angle ◽  
Jointed Rock ◽  
Roughness Coefficient ◽  
Rock Fractures ◽  
Shear Tests ◽  
Large Sample ◽  
Peak Friction Angle ◽  
Peak Shear Stress

An accurate understanding of jointed rock mass behavior is important in many applications ranging from deep geological disposal of nuclear waste, to deep mining, and to urban geoengineering projects. The roughness of rock fractures and the matching of the fracture surfaces are the key contributors to the shear strength of rock fractures. In this research, push shear tests with three normal stress levels of 3.6, 6.0, and 8.5 kPa were conducted on two granite samples with artificially induced well-matching tensile fractures with sizes of 500 mm × 250 mm and 1000 mm × 500 mm. The large sample reached on average a −60% weaker peak shear stress than the medium-sized sample, and a strong negative scale effect was observed in the peak shear strength. The roughness of the surfaces was measured using a profilometer and photogrammetry. The scale-corrected profilometer-based method (joint roughness coefficient, JRC) underestimates the peak friction angle for the medium-sized slabs by −27% for the medium sample and −9% for the large sample. The photogrammetry-based (Z′2) method produces an estimate with −7% (medium) and + 12% (large) errors. The photogrammetry-based Z′2 is an objective method that consistently produces usable estimates for the JRC and peak friction angle.

scholarly journals Overland Flow Resistance Law under Sparse Stem Vegetation Coverage

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1657
Author(s):  
Jingzhou Zhang ◽  
Shengtang Zhang ◽  
Si Chen ◽  
Ming Liu ◽  
Xuefeng Xu ◽  
...  
Keyword(s):  
Flow Resistance ◽  
Overland Flow ◽  
Vegetation Coverage ◽  
Dominant Factor ◽  
Roughness Coefficient ◽  
Hydraulic Parameters ◽  
Slope Condition ◽  
Manning Roughness ◽  
The Relationship ◽  
Manning Roughness Coefficient

To explore the characteristics of overland flow resistance under the condition of sparse vegetative stem coverage and improve the basic theoretical research of overland flow, the resistance characteristics of overland flow were systematically investigated under four slope gradients (S), seven flow discharges (Q), and six degrees of vegetation coverage (Cr). The results show that the Manning roughness coefficient (n) changes with the ratio of water depth to vegetation height (h/hv) while the Reynolds number (Re), Froude number (Fr), and slope (S) are closely related to vegetation coverage. Meanwhile, h/hv, Re, and Cr have strong positive correlations with n, while Fr and S have strong negative correlations with n. Through data regression analysis, a power function relationship between n and hydraulic parameters was observed and sensitivity analysis was performed. It was concluded that the relationship between n and h/hv, Re, Cr, Q, and S shows the same law; in particular, for sparse stem vegetation coverage, Cr is the dominant factor affecting overland flow resistance under zero slope condition, while Cr is no longer the first dominant factor affecting overland flow resistance under non-zero slope condition. In the relationship between n and Fr, Cr has the least effect on overland flow resistance. This indicates that when Manning roughness coefficient is correlated with different hydraulic parameters, the same vegetation coverage has different effects on overland flow resistance. Therefore, it is necessary to study overland flow resistance under the condition of sparse stalk vegetation coverage.

scholarly journals A New Method for Determination of Joint Roughness Coefficient of Rock Joints

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Shigui Du ◽  
Huicai Gao ◽  
Yunjin Hu ◽  
Man Huang ◽  
Hua Zhao
Keyword(s):  
Scale Effect ◽  
Fractal Model ◽  
Rock Joints ◽  
Effective Length ◽  
Roughness Coefficient ◽  
Joint Roughness Coefficient ◽  
Joint Roughness ◽  
Exposed Rock ◽  
Study Results

The joint roughness coefficient (JRC) of rock joints has the characteristic of scale effect. JRC measured on small-size exposed rock joints should be evaluated by JRC scale effect in order to obtain the JRC of actual-scale rock joints, since field rock joints are hardly fully exposed or well saved. Based on the validity analysis of JRC scale effect, concepts of rate of JRC scale effect and effective length of JRC scale effect were proposed. Then, a graphic method for determination of the effective length of JRC scale effect was established. Study results show that the JRC of actual-scale rock joints can be obtained through a fractal model of JRC scale effect according to the statistically measured results of the JRC of small-size partial exposed rock joints and by the selection of fractal dimension of JRC scale effect and the determination of effective length of JRC scale effect.

Research on the Development of the Logistics Industry

2014 ◽  
Vol 687-691 ◽  
pp. 4568-4572
Author(s):  
Hai Chen Zhan
Keyword(s):  
Economic Growth ◽  
Decision Making ◽  
Economic Development ◽  
Division Of Labor ◽  
Gansu Province ◽  
Policy Recommendations ◽  
Logistics Industry ◽  
The Social ◽  
Econometric Approach ◽  
The Relationship

Modern logistics industry as an emerging industry, with the industrial division of labor with the social refinement and depth, to promote China's economic development has become an important industry and new economic growth point. This paper uses econometric approach to relations of the logistics industry and economic growth in Gansu Province made an empirical analysis reveals and Reveals the relationship between logistics industry and economic development in Gansu Province And for the results of the analysis are summarized and give relevant policy recommendations, hoping to provide a reference for the development of decision-making in Gansu.

Investigation of Proppant Distributions in Rock Fractures With Applications to Hydraulic Fracturing

2021 ◽  
Author(s):  
Amir A. Mofakham ◽  
Farid Rousta ◽  
Dustin M. Crandall ◽  
Goodarz Ahmadi
Keyword(s):  
Fluid Flow ◽  
Hydraulic Fracturing ◽  
Oil And Gas ◽  
Fluid Dynamic ◽  
Rock Fracture ◽  
Experimental Investigations ◽  
Rock Fractures ◽  
Fracture Geometry ◽  
Injection Process ◽  
Fracking Fluid

Abstract Hydraulic fracturing or fracking is a procedure used extensively by oil and gas companies to extract natural gas or petroleum from unconventional sources. During this process, a pressurized liquid is injected into wellbores to generate fractures in rock formations to create more permeable pathways in low permeability rocks that hold the oil. To keep the rock fractures open after removing the high pressure, proppant, which typically are sands with different shapes and sizes, are injected simultaneously with the fracking fluid to spread them throughout rock fractures. The extraction productivity from shale reservoirs is significantly affected by the performance and quality of the proppant injection process. Since these processes occur under the ground and in the rock fractures, using experimental investigations to examine the process is challenging, if not impossible. Therefore, employing numerical tools for analyzing the process could provide significant insights leading to the fracking process improvement. Accordingly, in this investigation, a 4-way coupled Computational Fluid Dynamic and Discrete Element Method (CFD-DEM) code was used to simulate proppant transport into a numerically generated realistic rock fracture geometry. The simulations were carried out for a sufficiently long period to reach the fractures’ steady coverage by proppant. The proppant fracture coverage is a distinguishing factor that can be used to assess the proppant injection process quality. A series of simulations with different proppant sizes as well as various fracking fluid flow rates, were performed. The corresponding estimated fracture coverages for different cases were compared. The importance of proppant size as well as the fluid flow rate on the efficiency of the proppant injection process, were evaluated and discussed.

scholarly journals Decoupling of Land Use Intensity and Ecological Environment in Gansu Province, China

2020 ◽  
Vol 12 (7) ◽  
pp. 2779 ◽  
Author(s):  
Yanjie Zhang ◽  
Wei Song ◽  
Shun Fu ◽  
Dazhi Yang
Keyword(s):  
Land Use ◽  
Environmental Protection ◽  
Environmental Quality ◽  
Gansu Province ◽  
Ecological Environment ◽  
Human Society ◽  
Land Use Intensity ◽  
Land Use Efficiency ◽  
Use Efficiency ◽  
The Relationship

Land is the carrier of the production and living activities of human society and the basis of survival and development of all living organisms. With the continuous development of the social economy, the unreasonable use of land is becoming more and more serious, aggravating the deterioration of the ecological environment. Most studies in this field have mainly focused on land use changes and the corresponding impacts on the ecological environment, but relatively few studies have delinked the relationship between land use intensity and the ecological environment. Based on data on these two factors for Gansu Province from 1998 to 2017, we used the Tapio decoupling model to evaluate the decoupling relationship between land use intensity and ecological environment. From 1998 to 2017, the comprehensive land use intensity in Gansu province increased by 107.77%, and the comprehensive ecological environment index increased by 63.76%. In general, the relationship between land use intensity and ecological environment experienced five states, namely weak decoupling, strong negative decoupling, strong decoupling, expansive negative decoupling, and declining decoupling. During 1999–2013 and 2013–2016, land use intensity and ecological environment had decoupled, and the main reasons were as follows: (1) The Chinese government introduced a series of farmland protection policies and measures, controlled the area of newly added construction land, and reduced urban land expansion; (2) ecological restoration projects for mountains, forests, fields, lakes, and grassland strengthened the environmental protection in Gansu Province; and (3) in the process of economic development, the increased investment of technology and capital improved the land use efficiency, finally realizing the “double growth” of land use intensity and environmental quality. Based on these results, land use intensity and environmental quality are not necessarily contradictory, and a moderate improvement of land use efficiency and environmental protection can probably result in increased land use intensity and higher environmental quality.

scholarly journals A New Method to Estimate the Joint Roughness Coefficient by Back Calculation of Shear Strength

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Jiu-yang Huan ◽  
Ming-ming He ◽  
Zhi-qiang Zhang ◽  
Ning Li
Keyword(s):  
Shear Strength ◽  
Joint Model ◽  
Rock Joints ◽  
New Method ◽  
Roughness Coefficient ◽  
Shear Direction ◽  
Joint Roughness Coefficient ◽  
Joint Roughness ◽  
Back Calculation ◽  
Smooth Joint Model

The joint roughness coefficient (JRC) is an important factor affecting the shear properties of rock joints, and its accurate estimation is a challenging task in rock engineering. Existing JRC evaluation approaches such as the empirical comparison method and the statistical parameter method have some unresolved defects. In this study, a new method is proposed for JRC estimation to overcome the deficiencies of existing approaches based on back calculation of shear strength. First, the 10 standard roughness joints are established in numerical rock samples generated by the bonded particle method (BPM). Secondly, the microscopic parameters of the intact rock and joints are calibrated, and a series of direct shear tests of joint samples are carried out under different normal stresses. Finally, the empirical relationships between shear strength and JRC are proposed under high correlation conditions. The results show that the modified smooth joint model (MSJM) is proved to better simulate the mechanical properties of rough joints than the smooth joint model (SJM). When the shear strength of target joint is substituted in the corresponding relationship, the JRC of joint along the shear direction can be conveniently obtained. In addition, the JRC values of 10 standard roughness joint profiles under shear direction of from right to left (FRTL) are obtained. By estimating the JRC of 9 target joints in the literature, it can be seen that the new method proposed in this paper can well reflect the directionality of roughness and it is convenient to apply.

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