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Study of geo-mechanical characteristics and stability of half-tunnel at Dharapani along Besisahar—Chame road section, Manang
Published in Heping Xie, Jian Zhao, Pathegama Gamage Ranjith, Deep Rock Mechanics: From Research to Engineering, 2018
Most commonly used rock mass classifications—Rock Mass Rating (RMR), Rock Tunnelling Quality Index (Q) and Geological Strength Index (GSI) were used to classify the rock of chosen sections by line method. Joint properties based on Barton—Bandis model as shown in Eq. [1] and rock strength of the selected stretch had been determined during the field visit. Besides that, other geotechnical properties were determined in laboratory scale. () τ=σntan[Φb+JRClog10(JCSσn)] where, τ = shear strength of joints, σn = normal strength of joints, Φb = basic friction angle obtained by slide or tilt tests, JRC = Joint Roughness coefficient and JCS = Joint wall compressive strength
Practical estimate of rock mass strength and deformation parameters for engineering design
Published in Xia-Ting Feng, Rock Mechanics and Engineering, 2017
Different from other rock mass classification systems, the GSI system is directly linked to engineering parameters such as Mohr-Coulomb or Hoek-Brown strength parameters or rock mass deformation modulus. The original GSI system, which is applied mainly for the estimation of the peak strength, is based on a descriptive approach, rendering the system somewhat subjective and difficult to use for inexperienced personnel. To assist the use of the GSI system, a supplementary quantified approach for the GSI system, which incorporates quantitative measures of block volume and joint surface condition factor, can be used. The block volume can be calculated, in most cases, from joint spacings of three dominant joint sets. The joint condition factor is obtained by rating joint roughness depending on the large-scale waviness, small-scale smoothness of joints, and joint alteration depending on the weathering and infillings in joints.
Characteristics of rock mass
Published in Yanrong Li, Handbook of Geotechnical Testing, 2019
In engineering, the purpose of rock mass classification is to comprehensively analyse the geological conditions that affect the stability and the physical and mechanical properties of rock masses. The classification divides rock masses into several categories with different degrees of stability to guide planning, design and construction. Two examples of internationally applied engineering classification systems of rock masses are the rock mass rating (RMR) system proposed by Bieniawski (1974, 1984) and the tunnelling quality index (Q) system proposed by Barton et al. (1974).
Research on failure mechanism and support technology of fractured rock mass in an undersea gold mine
Published in Geomatics, Natural Hazards and Risk, 2023
Xingdong Zhao, Qiankun Zhu, Erik Westman, Shanghuan Yang
There are many rock mass classification methods, the most influential and most commonly used rock mass classification methods are Geomechanics Classification or the Rock Mass Rating (RMR) (Bieniawski 1989), Rock Mass Quality (Q) (Barton 2002) and Geological Strength Index (GSI) (Marinos and Hoek 2000). According to the discontinuities investigation results (Table 1) and rock mechanics experiments results (Appendix A), the physical and mechanical parameters required for rock mass quality classification in each mining level are obtained. Three rock mass classification methods are used to classify the quality of fractured rock mass in drift at −200 m to −440 m mining level in southwest part of Xinli Gold Mine (Table 2), and RMR and GSI were assessed independently. The zoning of surrounding rock was according to the rock mass classification results.
Assessing stope performance using georeferenced octrees and multivariate analysis
Published in Mining Technology, 2023
Benoît McFadyen, Martin Grenon, Kyle Woodward, Yves Potvin
Mine sites will look to maximise stope performance by using tools which typically include rock mass classification charts, numerical modelling and the Stability Chart (Mathews et al. 1981). These tools are used during the first two steps of the design process to facilitate decision-making. Rock mass classification charts developed by Barton et al. (1974) (Q-system) and Bieniawski (1973) (RMR system) were amongst the first tools developed for quantifying the properties of the rock mass. Despite this framework originally being developed for civil tunnelling applications, since their inception, they have been widely used in mining and more specifically stope design. Numerical modelling is used for estimating the stress redistribution around the stope. It considers geological and geomechanical properties, as well as the stope geometry and mining sequence (Potvin 1988).
Demarcation of probable failure zones based on SMR and kinematic analysis
Published in Geomatics, Natural Hazards and Risk, 2019
S. Kumar, H. K. Pandey, P. K Singh, K. Venkatesh
Among various available rock mass classification techniques, rock mass rating (RMR) is undoubtedly a helpful tool for rock mass characterization, planning and design in engineering applications, but with due consideration of the limits and applicability in each geological setting in relation to different engineering geological problems. RMR technique is based on detailed field and laboratory study which involves collection of data at site slopes, strength of rock exposed on slope face, spacing of discontinuities, orientation of discontinuities, and ground water condition. Despite several benefits of RMR, the technique itself does not provide much information about the failure mode and direction off movement. In addition, rock quality designation, a parameter used in RMR, gives poor results for highly jointed and weak rock mass. Slope mass rating (SMR) developed using basic RMR is a much better tool to study slopes and have been applied worldwide to understand the stability and probability of failure for natural and engineered slopes (Romana 1985; Romana et al. 2003; Umrao et al. 2011). The SMR method for slope stability analysis has all the basic parameters of RMR as well as it also includes some adjustment factors of the slope-joint interaction and the impact of method of excavation (Sujatha and Thirukumaran 2018). In the present study, RQD has been calculated using Volumetric joint of rock mass (Palmstrom 1974).