scholarly journals Correlation between Rock mass rating, Q-system and Rock mass index based on field data

2018 ◽  
Vol 149 ◽  
pp. 02030
Author(s):  
Amine Soufi ◽  
Lahcen Bahi ◽  
Latifa Ouadif ◽  
Jamal Eddine Kissai
Keyword(s):  
Rock Mass ◽  
Quality Index ◽  
Correlation Coefficients ◽  
Original Data ◽  
Classification Systems ◽  
Strong Correlations ◽  
Rock Mass Quality ◽  
Silver Mine ◽  
Mass Classification

Throughout the last decades, many authors have published empirical correlations between rock mass classification systems that have arisen from a series of measurements and observations with the special conditions of the work site; this means that the validity of these expressions is strongly dependent on the knowledge of the original data from which they were deduced. Consequently, none of these expressions are universal nowadays. In recent years, the principal corps B3 “CPB3” of IMITER mine area has witnessed massive mining activities involving a large amount of underground excavation, the rock mass characteristics are undoubtedly the essential requirements for empirical design and numerical modeling. Therefore, the research carried out aims to provide a new specific inter-relation between the most widespread Quality Indexes, Bieniawski’s RMR Quality Index, Barton’s Q Quality Index and Palmström’s RMi Mass index utilizing the data gathered from the jointed volcano-sedimentary rock mass of the “CPB3”. The “CPB3” mining level is located in Imiter silver mine, eastern Anti-Atlas, Morocco, at a depth of 500m. A total of 128 rock blocks were examined for the rock mass quality using the three characterization systems, the outcrop mapping was carried out on freshly parallel exposed faces in the horizontal south to north direction. After processing and plotting the in-situ measured data, several equations of the three indexes has been investigated using regression modeling to analyze the obtained results and find the most suitable equation with the highest correlation coefficients. These relationships were then compared with those reported in the literature. The proposed regression models reveal strong correlations between RMR, Q and RMi indexes with high values of accuracy coefficients so that they can be used to estimate the “CPB3” underground rock mass quality for the range of RMR between 30% and 80%. The developed mathematical formulations of the geomechanicalindexes will certainly offer an effective tool to geologist and geotechnical professionals in the decision-making process, preliminary design phase, stability problems and suggestions of the required supporting system and techniques without the expense of more resources or time.

scholarly journals Weightage Effect during Back-Calculation of Rock-Mass Quality from the Installed Tunnel Support in Rock-Mass Rating and Tunneling Quality Index System

2019 ◽  
Vol 9 (10) ◽  
pp. 2065 ◽  
Author(s):  
Jonguk Kim ◽  
Hafeezur Rehman ◽  
Wahid Ali ◽  
Abdul Muntaqim Naji ◽  
Hankyu Yoo
Keyword(s):  
Rock Mass ◽  
Quality Index ◽  
Rock Bolt ◽  
Rock Mass Rating ◽  
Rock Mass Quality ◽  
Back Calculation ◽  
The Difference ◽  
Bolt Spacing ◽  
Q System ◽  
Selection Of

In extensively used empirical rock-mass classification systems, the rock-mass rating (RMR) and tunneling quality index (Q) system, rock-mass quality, and tunnel span are used for the selection of rock bolt length and spacing and shotcrete thickness. In both systems, the rock bolt spacing and shotcrete thickness selection are based on the same principle, which is used for the back-calculation of the rock-mass quality. For back-calculation, there is no criterion for the selection of rock-bolt-spacing-based rock-mass quality weightage and shotcrete thickness along with tunnel-span-based rock-mass quality weightage. To determine this weightage effect during the back-calculation, five weightage cases are selected, explained through example, and applied using published data. In the RMR system, the weightage effect is expressed in terms of the difference between the calculated and back-calculated rock-mass quality in the two versions of RMR. In the Q system, the weightage effect is presented in plots of stress reduction factor versus relative block size. The results show that the weightage effect during back-calculation not only depends on the difference in rock-bolt-spacing-based rock-mass quality and shotcrete along with tunnel-span-based rock-mass quality, but also on their corresponding values.

scholarly journals Joint Investigation and 3D Visual Evaluation of Rock Mass Quality

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Haiping Yuan ◽  
Chenghao Chen ◽  
Yixian Wang ◽  
Hanbing Bian ◽  
Yan Liu
Keyword(s):  
Rock Mass ◽  
Quality Evaluation ◽  
Evaluation Method ◽  
Three Dimensional ◽  
Rock Mass Classification ◽  
National Standard ◽  
Ratio Method ◽  
Rock Mass Quality ◽  
Close Range ◽  
Mass Classification

In order to realize the high efficiency quality classification and three-dimensional visualization of engineering rock mass and to solve the technical difficulties of the traditional rock mass quality evaluation method such as high labor intensity, long process time consumption, many intervention processes such as scale measurement and manual calculation, and nonintuitive classification results, this paper puts forward a 3D visual rock mass quality evaluation method and system based on close-range photography, which optimizes the traditional rock mass quality evaluation method, makes the rock mass classification three-dimensional and visible, and realizes the estimation of unrevealed rock mass quality evaluation index. The research results show the following: (1) The method of storing joint information by close-range photography and extracting joint information by human-computer interaction improves the working efficiency and the process is safe and controllable compared with the traditional method of collecting fracture parameters. (2) Based on the statistical analysis of 97 groups of roadway survey data, the comprehensive statistical regression formula between BQ value of Chinese national standard and RMR value is given, and there is a good correlation between BQ value and RMR value of rock mass quality index. (3) Based on the power-inverse ratio method, the three-dimensional model of rock mass classification of the mine was established, and the cutting model obtained the current distribution diagram of rock mass quality grade, providing scientific reference for drilling, blasting, support, and other production design optimizations.

Why the future of rock mass classification systems requires revisiting their empirical past

2021 ◽  
pp. qjegh2021-039
Author(s):  
Beverly Yang ◽  
Amichai Mitelman ◽  
Davide Elmo ◽  
Doug Stead
Keyword(s):  
Rock Mass ◽  
Rock Mass Classification ◽  
Classification Systems ◽  
Empirical Knowledge ◽  
Rock Engineering ◽  
Geotechnical Data ◽  
Use Of Technology ◽  
Data Collection Process ◽  
Engineering Problems ◽  
Mass Classification

Despite recent efforts, digitisation in rock engineering still suffers from the difficulty in standardising and statistically analysing databases that are created by a process of quantification of qualitative assessments. Indeed, neither digitisation nor digitalisation have to date been used to drive changes to the principles upon which, for example, the geotechnical data collection process is founded, some of which have not changed in several decades. There is an empirical knowledge gap which cannot be bridged by the use of technology alone. In this context, this paper presents the results of what the authors call a rediscovery of rock mass classification systems, and a critical review of their definitions and limitations in helping engineers to integrate these methods and digital acquisition systems. This discussion has significant implications for the use of technology as a tool to directly determine rock mass classification ratings and for the application of machine learning to address rock engineering problems.

Comparison of rock mass classification systems

2007 ◽  
Vol 43 (4) ◽  
pp. 404-408 ◽  
Author(s):  
R. Rahmannejad ◽  
H. Mohammadi
Keyword(s):  
Rock Mass ◽  
Rock Mass Classification ◽  
Classification Systems ◽  
Mass Classification

scholarly journals Effects Of Different Empirical Design Approaches For Size Galleries On The Behaviour Of Rock Masses During The Excavation Operation: Excavation Case At BAE Well

2021 ◽  
Vol 12 (5) ◽  
pp. 1167-1177
Author(s):  
Ismail Zaki, Et. al.
Keyword(s):  
Rock Mass ◽  
Support Systems ◽  
Resistance Index ◽  
In Situ Stress ◽  
Tunnel Excavation ◽  
High In Situ Stress ◽  
Rock Mass Quality ◽  
Empirical Approaches ◽  
Empirical Design

The characterization of rock massifs is a delicate job; indeed, it is possible to understand the behaviour of intact rocks individually by laboratory tests but it is difficult to characterize them on the whole rock mass, which has undergone a complex geological history. Empirical approaches play an important role in the excavation of galleries and the design of support systems. These approaches are considered very effective in optimizing the tunnel excavation process. Several reliable empirical approaches have been developed, but the selection or use of an appropriate empirical method to design the tunnel excavation remains a difficult task. Therefore, in this work, the analysis of four approaches, the most used, of different empirical design was carried out to determine the behaviour of the rock mass during its excavation in a state of high in situ stress. This study was carried out on the scale of the ST2 rock mass of the worksite (BAE well 3) at the Bouazzer mine. These approaches include the AFTES classification, rock mass index (RMR), rock mass quality (Q) and geological resistance index (GSI). Based on the simulated statistical results obtained from said empirical approaches, through the finite element calculation, it was found that the application of the rock mass quality approach is very efficient in the excavation of the rock mass. gallery of size because it makes it possible to take into account the equivalent dimensions of the gallery, the stress condition in situ due to the excavation and the heights of overburden which are considered as major elements of the stability of the gallery. The method provides an optimized reinforcement and support design. In addition, this study will serve as a valuable basic document for the geotechnical engineer to design and plan support systems in the excavation of galleries under high in-situ stress.

scholarly journals Correlation of P-wave Velocity with Rock Quality Designation (RQD) in Volcanic Rocks

2019 ◽  
Vol 3 (2) ◽  
pp. 11
Author(s):  
Ainul Fatayaatis Salaamah ◽  
Teuku Faisal Fathani ◽  
Wahyu Wilopo
Keyword(s):  
Rock Mass ◽  
Wave Velocity ◽  
Volcanic Rocks ◽  
Rock Mass Classification ◽  
Classification Systems ◽  
P Wave ◽  
Rock Quality Designation ◽  
Rock Quality ◽  
P Wave Velocity ◽  
Mass Classification

One important part of rock mass investigation is the geomechanical assessment in terms of rock mass classification systems. Rock mass classification is one of themost efficient methods in rock mechanics to provide a basic understanding of rock masscharacterization. Rock mass properties can be determined by a seismic refraction surveyas an indirect geophysical assessment. In this study, the P-wave velocity from seismicrefraction was compared with the Rock Quality Designation (RQD) from the boreholes.The empirical correlation between the RQD and the P-wave velocity was found by usingthe linear regression analysis. The RQD value estimated from the P-wave velocity can beapplied for tropical environment study with geological conditions of volcanic rocks. This study helps to estimate and predict the subsurface rock quality, to reduce investigation costs, and to improve understanding of subsurface rock quality.

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