Evaluating Rock Mass Properties of Vipingo Coral Limestone Quarry Based on a Modified Geological Strength Index (GSI) and State of Karstification

The main purposes of the present study are to evaluate pilot grouting and to develop regression equations for prediction of grout intake. There are no permeability problems with the sandstone-siltstone-claystone alternations and basement clayey limestone at the dam site. Karstic limestone block is permeable due to karstification and heavy discontinuities. For the purpose of the study, Q system, geological strength index (GSI), secondary permeability index (SPI), joint spacing (JSP), joint apertures (Ap), Lugeon (Lu), and the permeability coefficient (k) were determined. Karstic limestone block rock mass properties correlated with grouting material amount. A series of simple and multiple nonlinear regression analyses was performed between grout take material amount (Gt) and average values of these rock mass properties. Significant determination coefficients were determined. Prediction capacity of the empirical equations were also examined with root mean square error (RMSE), values account for (VAF), mean absolute percentage error (MAPE), and prediction error evaluations. Considering simple regression analyses, the equation derived with Gt-SPI gives the best performance. The best prediction is determined with the equation derived with rock quality designation values (RQD), SPI, and joint aperture as input parameters with the multiple nonlinear regression analysis, in addition to this, other empirical equations also provide acceptable results.

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ESTIMATION OF THE GEOLOGICAL STRENGTH INDEX SYSTEM FOR CAVITY LIMESTONE LAYER IN QUARRY AREA, REMBANG, CENTRAL JAVA PROVINCE, INDONESIA

Journal of Applied Geology ◽

10.22146/jag.7209 ◽

2015 ◽

Vol 5 (2) ◽

Author(s):

R. Andy Erwin Wijaya ◽

Dwikorita Karnawati ◽

Srijono Srijono ◽

Wahyu Wilopo

Keyword(s):

Rock Mass ◽

Solution Process ◽

Geological Strength Index ◽

Strength Index ◽

Mine Design ◽

Weak Zone ◽

Limestone Quarry ◽

Rock Mass Characterization ◽

Rock Mass Quality ◽

Geological Conditions

Limestone mining needs a good mine design which is safe for the environment. Mine design is determined by the rock mass quality. The rock mass quality in each mine location is not necessary the same depending on the geological conditions. The research area is located in limestone quarry of Sale District, Rembang Regency, Center Java Province-Indonesia. In the limestone quarry area, there is cavity zone which consists of cavity limestone layer at the wall of quarry bench. This cavity layer in limestone quarry has occurred by solution process. The cavity layer zone is a potentially weak zone which has caused bench failures in the limestone quarry area. The objective of this research is to analyze the rock mass quality in the cavity limestone layer using Geological Strength Index (GSI) system. Final result of the research is a rock mass characterization, specifically for cavity limestone layer. Keywords: geological strength index, limestone, cavity layer

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

Applied Sciences ◽

10.3390/app11083351 ◽

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.

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

Bulletin of Engineering Geology and the Environment ◽

10.1007/s10064-021-02368-2 ◽

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.

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