scholarly journals Mechanical Parameters of Deep-Buried Coal Goaf Rock Mass Based on Optimized GSI Quantitative Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Qingqiu Wang ◽  
Mo Xu ◽  
Yunhui Zhang ◽  
Xinyu Cen ◽  
Xingwang Chang
Keyword(s):  
Rock Mass ◽  
Surface Condition ◽  
Geological Strength Index ◽  
Mechanical Parameters ◽  
Rock Types ◽  
Integrity Index ◽  
Disturbance Factor ◽  
Structural Surface ◽  
Test Result ◽  
Quantitative Formula

In order to obtain the accurate mechanical parameters of deep-buried coal goaf rock mass, the limitation of geological strength index (GSI) in concealed rock mass is analyzed. Based on the test result and analysis of the current normative standards, the classification indexes of rock mass structural are optimized based on discontinuity distance d and rock mass integrity index K v . The ratio of rock mass saturated strength to dry strength, η, is introduced, quantization formula of structural surface conditions is proposed, and the influence of groundwater and rock types is included in structural surface condition classification. The GSI system is improved to better suit all types of deep-buried and water-rich rock masses. Furthermore, the rock mass disturbance factor D’s quantitative formula is listed according to the Hoek–Brown (HB) criterion. Taking the goaf roof under railway as an example, the parameters of deep-buried rock mass are obtained based on the improved quantitative GSI system and HB criterion. This research provides a scientific reference for achieving geological parameters and engineering designing in goaf areas.

scholarly journals Sensitivity Analysis in the Estimation of Mechanical Parameters of Engineering Rock Mass Based on the Hoek–Brown Criterion

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhiqiang Li ◽  
Guofeng Liu ◽  
Shuqian Duan ◽  
Shufeng Pei ◽  
Changgen Yan
Keyword(s):  
Rock Mass ◽  
Triaxial Compression ◽  
Damage Zone ◽  
Surrounding Rock ◽  
Geological Strength Index ◽  
Sensitivity Factor ◽  
Mechanical Parameters ◽  
Compression Tests ◽  
Disturbance Factor

Geological strength index GSI, disturbance factor (D), material constant mi, and uniaxial compressive strength σci of the intact rock are essential input parameters IPs of the Hoek–Brown H−B criterion. Mechanical parameters MPs of the engineering rock mass, including elastic modulus E, cohesion c, and internal friction angle φ estimated by the H–B criterion, and the predicted excavation response of surrounding rock, including the displacement and excavation damage zone EDZ based on the MPs, are of high relevance with the four IPs of the H–B criterion. In this paper, the deep and huge underground cavern excavated in basalt from a hydropower station under construction in the southwest of China is used to analyse the sensitivity of the IPs on the MPs, the displacement, and EDZ of the surrounding rock mass. Firstly, the H–B criterion is applied to estimate the MPs, among which the IPs are obtained from a series of in situ and laboratory tests, including borehole camera observation, wave velocity test, uniaxial and triaxial compression tests, and so on. Secondly, the sensitivity relationships between IPs, MPs, and prediction results of displacement and EDZ are established and described quantitatively by the sensitivity factor (si). Results show that the MPs of the rock mass are more sensitive to GSI and D⋅GSI and σci are high-sensitivity parameters affecting the displacement and EDZ. Finally, the variations in the estimated MPs and associated prediction results concerning excavation response, which are caused by the uncertainties in the determination of the IPs, are further quantified. This study provides a straightforward assessment for the variability of the rock mass parameters estimated by the H–B criterion. It also gives a valuable reference to similar geotechnical engineering for the determination of rock mass parameters in the preliminary design.

scholarly journals Study of Rock Mass Rating (RMR) and Geological Strength Index (GSI) Correlations in Granite, Siltstone, Sandstone and Quartzite Rock Masses

2021 ◽  
Vol 11 (8) ◽  
pp. 3351
Author(s):  
Gabor Somodi ◽  
Neil Bar ◽  
László Kovács ◽  
Marco Arrieta ◽  
Ákos Török ◽  
...  
Keyword(s):  
Rock Mass ◽  
Linear Equations ◽  
Geological Strength Index ◽  
Gold Mine ◽  
Strength Index ◽  
Comprehensive Understanding ◽  
Rock Types ◽  
Mass Classification ◽  
Waste Repository ◽  
And Performance

A comprehensive understanding of geological, structural geological, hydrogeological and geotechnical features of the host rock are essential for the design and performance evaluation of surface and underground excavations. The Hungarian National Radioactive Waste Repository (NRWR) at Bátaapáti is constructed in a fractured granitic formation, and Telfer Gold Mine in Australia is excavated in stratified siltstones, sandstones and quartzites. This study highlights relationships between GSI chart ratings and calculated GSI values based on RMR rock mass classification data. The paper presents linear equations for estimating GSI from measured RMR89 values. Correlations between a and b constants were analyzed for different rock types, at surface and subsurface settings.

scholarly journals Rock Mass Rating and Geological Strength Index of rock masses of Thopal-Malekhu River areas, Central Nepal Lesser Himalaya

2013 ◽  
Vol 16 ◽  
pp. 29-42 ◽  
Author(s):  
Jaya Laxmi Singh ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Rock Mass ◽  
Surface Condition ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Rock Slopes ◽  
Lesser Himalaya ◽  
Rock Masses ◽  
Strength Index ◽  
Rock Mass Structure ◽  
Exposed Rock

The rock slopes of the Thopal-Malekhu River areas, Lesser Himalaya, were characterized applying various systems of rock mass classification, such as Rock mass Rating (RMR) and Geological Strength Index (GSI), because the study area comprises well exposed rock formations of the Nawakot and Kathmandu Complexes, across the Thopal-Malekhu River areas. In RMR system, mainly five parameters viz. Uniaxial Compressive Strength (UCS) of rock, Rock Quality Designation (RQD), spacing of discontinuity, condition of discontinuity, and groundwater condition were considered. The new GSI charts, which were suitable for schistose and much disintegrated rock masses, were used to characterize rock slopes based on quantitative analysis of the rock mass structure and surface condition of discontinuities. RMR ranged from 36 to 82 (poor to very good rock mass) and GSI from 13.5±3 to 58±3 (poor to good rock mass). Slates (of the Benighat Slate) are poor rock masses with low strength, very poor RQD, and close to very close spacing of discontinuity, and dolomites (Dhading Dolomite) are fair rocks with disintegrated, poorly interlocked, and heavily broken rock masses yielding very low RMR and GSI values. Phyllites (Dandagaun Phyllite), schist (Robang Formation) and quartzite (Fagfog Quartzite, Robang Formation and Chisapani Quartzite), dolomite (Malekhu Limestone), and metasandstone (Tistung Formation) are fair rock masses with moderate GSI and RMR values, whereas quartzose schist and gneiss (Kulekhani Formation) are very good rock masses having comparatively higher RMR and GSI. The relationship between GSI and RMR shows positive and good degree of correlation. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8882   Bulletin of the Department of Geology Vol. 16, 2013, pp. 29-42

Macro-Mechanical Parameters Analysis of Rock Slope Based on the Partition Classification Method

2013 ◽  
Vol 790 ◽  
pp. 310-315
Author(s):  
Jun Wang ◽  
Cheng Jun Peng
Keyword(s):  
Rock Mass ◽  
Classification Method ◽  
Left Bank ◽  
Mechanical Parameters ◽  
The Finite Element Method ◽  
Stability Calculation ◽  
Rock Types ◽  
Structure Surface ◽  
The Stability ◽  
Engineering Stability

Accurate mechanics parameters are the precondition of reasonable calculation in the finite element method to calculate the deformation and stability of the rock mass engineering stability. Partition classification method can be used in the simulation of macro-mechanics parameters of rock mass, for the distribution of multiple sets of multi-level joint fissure in some engineering rock, the parameters of the rock mass can be simulated using the numerical method step by step or by group. Based on the partition classification method, the paper simulated the macro-mechanics parameters of natural slope upstream the left bank toe board of Maerdang hydropower station. The slope is divided into three areas according to the rock types and intensity, weathering degree, fracture, the trend and tendency of the fault, spacing and connected rate of the structure surface, the mechanics parameters of the structure surface, the groundwater conditions, and then use the partition classification method to calculate the region's macro-mechanical parameters, the results can be used to provide amount of reasonable parameters for the stability calculation of the slope in the subsequent deformation.

scholarly journals THE USE OF GEOLOGICAL STRENGTH INDEX GSI. RECOMMENDATIONS, LIMITATIONS AND RANGES OF VALUES IN MOST COMMON ROCK TYPES

2004 ◽  
Vol 36 (4) ◽  
pp. 1767 ◽  
Author(s):  
Β. Μαρίνος ◽  
Π. Μαρίνος ◽  
E. Hoek
Keyword(s):  
Rock Mass ◽  
Structural Characteristics ◽  
Geological Strength Index ◽  
Rock Masses ◽  
Strength Index ◽  
Rock Types ◽  
Quantitative Characterisation ◽  
General Guidance

After one decade of application of the Geological Strength Index, GSI, and its extensions, in the quantitative characterisation of the rock mass, the present paper attempts to answer the questions that have been raised by the users about the determination of the GSI for various qualities of rock masses and various conditions. Recommendations are given and cases are discussed where GSI is not applicable. The paper also gives general guidance on the field of GSI values of rock masses for the most common rock types based on their pétrographie and their most usual structural characteristics.

scholarly journals Influence of the groundwater level on the bearing capacity of shallow foundations on the rock mass

2021 ◽  
Author(s):  
Ana Alencar ◽  
Rubén Galindo ◽  
Svetlana Melentijevic
Keyword(s):  
Rock Mass ◽  
Bearing Capacity ◽  
Groundwater Level ◽  
Sensitivity Study ◽  
Shallow Foundations ◽  
Unit Weight ◽  
Geological Strength Index ◽  
Strength Index ◽  
Mass Type

AbstractThe presence of the groundwater level (GWL) at the rock mass may significantly affect the mechanical behavior, and consequently the bearing capacity. The water particularly modifies two aspects that influence the bearing capacity: the submerged unit weight and the overall geotechnical quality of the rock mass, because water circulation tends to clean and open the joints. This paper is a study of the influence groundwater level has on the ultimate bearing capacity of shallow foundations on the rock mass. The calculations were developed using the finite difference method. The numerical results included three possible locations of groundwater level: at the foundation level, at a depth equal to a quarter of the footing width from the foundation level, and inexistent location. The analysis was based on a sensitivity study with four parameters: foundation width, rock mass type (mi), uniaxial compressive strength, and geological strength index. Included in the analysis was the influence of the self-weight of the material on the bearing capacity and the critical depth where the GWL no longer affected the bearing capacity. Finally, a simple approximation of the solution estimated in this study is suggested for practical purposes.

scholarly journals Rock Mass Assessment using Geological Strength Index (GSI) along the Ranau-Tambunan Road, Sabah, Malaysia

2016 ◽  
Vol 12 (1) ◽  
pp. 108-115 ◽  
Author(s):  
Norbert Simon ◽  
Rodeano Roslee ◽  
Abdul Ghani Rafek ◽  
Goh Thian Lai ◽  
Noran Nabilla Nor Azlan ◽  
...  
Keyword(s):  
Rock Mass ◽  
Geological Strength Index ◽  
Strength Index

scholarly journals Sensitivity analysis of GSI based mechanical parameters of the rock mass

2014 ◽  
Vol 58 (4) ◽  
pp. 379-386 ◽  
Author(s):  
Péter Ván ◽  
Balázs Vásárhelyi
Keyword(s):  
Sensitivity Analysis ◽  
Rock Mass ◽  
Mechanical Parameters
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