On the influence of rock mass quality on the quality of blasting work in tunnel driving

1998 ◽  
Vol 13 (1) ◽  
pp. 81-89 ◽  
Author(s):  
N. Innaurato ◽  
R. Mancini ◽  
M. Cardu
Keyword(s):  
Rock Mass ◽  
Rock Mass Quality

scholarly journals Analysis of engineering geology conditions based on the quality of rock mass in the Tiga Dihaji Dam’s diversion tunnel, South Sumatera, Indonesia

2021 ◽  
Vol 325 ◽  
pp. 05001
Author(s):  
Zekrinaldi ◽  
Ferian Anggara ◽  
Hendy Setiawan
Keyword(s):  
Rock Mass ◽  
Geological Strength Index ◽  
Strength Index ◽  
Diversion Tunnel ◽  
Rock Mass Quality ◽  
Geological Conditions ◽  
Q System

This research has examined the rock mass quality case study in the Tiga Dihaji Dam’s diversion tunnel. Observations of geological conditions were carried out on the surface and subsurface of the study site and show that the study area consists of tuffaceous sandstone and carbonate interbeds. The method of this study is based on the classification of the Geological Strength Index (GSI), Rock Mass Rating (RMR), and the Q-system. The results indicate that tuffaceous sandstone has a GSI value of 15 - 87.5 (very poor - very good), RMR 48 - 82 (fair - very good), and Q-system 0.01 – 60.0 (exceptionally poor - very good). Meanwhile, carbonate interbeds have a low value, with a GSI value of 10.5 - 77.5 (very poor to very good), RMR 17.0 – 56.0 (very - poor fair), and Q-system 0 - 35.2 (exceptionally poor - good). Moreover, a correlation was made between rock mass quality for conditions in the study area. The correlation between GSI and RMR was obtained by the equation GSI = 2.2885RMR 82.567 (R2 = 0.6653), RMR and Q-system RMR = 2.0175ln(Q) + 63.061 (R2 = 0.4987), and GSI and Q-system GSI = 7.2119ln(Q) 54.578 (R2 = 0.8095).

scholarly journals Probabilistic Approach for Assessing Rock Mass Quality in the Tunnel

2012 ◽  
Vol 11 ◽  
pp. 6-11
Author(s):  
Krishna Kanta Panthi
Keyword(s):  
Rock Mass ◽  
Heterogeneous Media ◽  
Probabilistic Approach ◽  
Cost Effective ◽  
Quality Data ◽  
Rock Mass Quality ◽  
Headrace Tunnel ◽  
Key Issues ◽  
Tunnel Alignment

Rock mass is a heterogeneous media and the quality of the rock mass may change within a very short distance. As a result, on many occasions considerable discrepancies (variations) have been found between the predicted and actual rock mass conditions along the tunnel alignment, resulting in signifi cant cost and time overruns. Finding innovative solutions for quantifying the quality of rock mass and assessing the risk of discrepancies are, therefore, key issues for cost effective and optimum tunneling solutions in the Himalayan region.In this paper, a probabilistic approach of uncertainty analysis has been proposed to evaluate the quality of rock mass based on the Q-system of rock mass classifi cation. Mapped rock mass quality data from the Modi headrace tunnel from Nepal have been used as a case study. The degree of correlation between the simulated results achieved by a probabilistic assessment using @Risk and values actually measured in the tunnel have been discussed. It is concluded that the probabilistic approach can be used as a tool in predicting rock mass quality and assessing risk in tunneling projects.DOI: http://dx.doi.org/10.3126/hn.v11i0.7154 Hydro Nepal Vol.11 2011 pp.6-11

scholarly journals Rock mass blastability dependence on rock mass quality.

2013 ◽  
Vol 47 (4) ◽  
pp. 1694 ◽  
Author(s):  
M. Chatziangelou ◽  
B. Christaras
Keyword(s):  
Rock Mass ◽  
Classification System ◽  
Quality Characteristics ◽  
Classification Systems ◽  
New Classification ◽  
The Poor ◽  
Rock Mass Quality ◽  
To Come ◽  
Blastability Index

The present paper tries to investigate the influence of rock mass quality characteristics on blasting results. In order to come to some conclusions, blastability and quality of rock mass were put together using the already known classification systems. Taking into account the quantity of blastability index (BI) for every possible structural appearance of the poor rock mass, the relation of discontinuities characteristics and blastability index are investigated. The estimations of the above trial gave arise on a new classification system being called “Blastability Quality System (BQS)”, which can be an easily and wide use tool as it is a quickly calculator for blastability index (BI) and rock mass quality.

ethodical principles of designing the formation of rock mass quality for lump sorting scheelite-containing ores at the stage of mining

2019 ◽  
Vol 8 (29) ◽  
pp. 3-17
Author(s):  
V.A. Khakulov ◽  
◽  
V.A. Shapovalov ◽  
V.N. Ignatov ◽  
Zh.V. Karpova ◽  
...  
Keyword(s):  
Rock Mass ◽  
Rock Mass Quality

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 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.

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