Excavation method and support system in the diversion tunnel of Tiga Dihaji Dam, South Sumatera, Indonesia based on the rock mass quality

The Bener Dam Diversion Tunnel Plan is located in Bener District, Purworejo Regency. Engineering geology mapping data, drillimg data and laboratory data used as primary data. Surface and subsurface analysis show that each rock unit has different index and mechanical properties. Generally, the rock mass quality conditions in the dam belonged to good Rock (80%) in the Rock Mass Rating (RMR) system (Bieniawski, 1989). The other rock mass quality type also found among them fair rock (5%), poor rock (5%), and very poor rock (10%). Poor rock mass quality conditions were controlled by geological structures, especially faults that partially cut through the tunnel geometry. The very poor quality of rock mass was in the volcanic lens (loose sand material) did not cut through the tunnel path. The difference stand-up time of the rock on the tunnel requires proper mitigation (Nguyen Nguyen, 2015). The stand-up time belonged to the dangerous condition was in the fault zone with poor rock mass quality, while the lens with very bad rock mass quality did not affect the stability of the excavation of the tunnel.

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

E3S Web of Conferences ◽

10.1051/e3sconf/202132505001 ◽

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).

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Recommendations of excavation and support systems of Pamukkulu Dam diversion tunnel based on correlation of rock mass classification between RMR and GSI

E3S Web of Conferences ◽

10.1051/e3sconf/202132504002 ◽

2021 ◽

Vol 325 ◽

pp. 04002

Author(s):

Dico Nasrulloh ◽

Agung Setianto ◽

I Gde Budi Indrawan

Keyword(s):

Rock Mass ◽

Support System ◽

Rock Mass Classification ◽

Geological Strength Index ◽

Class Iii ◽

Tunnel Face ◽

Diversion Tunnel ◽

Engineering Research ◽

Mass Classification ◽

Drill And Blast

This paper presents the results of geological engineering research conducted to determine the character of rock masses, recommendations of tunnel excavation method and support system based on standup time estimates in unsuported conditions. The investigation was conducted by observing rock mass quality based on the newest bore log sample test results in 2019 using Rock Mass Rating (RMR) and Geological Strength Index (GSI) rock mass classification. The results showed that area consist of lithology in the form of porphyryc lava basalt and pyroclastic volcanic breccia. Rock mass has a slightly weathering alteration rates. Intact rocks have Uniaxial Compressive Strength (UCS) values ranging from 100-250 Mpa to >250 Mpa and are a category of strong rocks. Rock mass has fair to good rock quality class III-II based on RMR values between 53-69, GSI values between 48-64. The roof span required is obtained from the tunnel planning roof span of 10 meter, with a stand-up time of 70 hours without support system and immediate collapse for 5 days. The recommended excavation methods are excavation by drill and blast on top heading and bench: 1,5-3 meter advance in top heading tunnel face, and then can be recommended support system using rock bolts (20 mm diameter, fullly bonded): systematic bolts 4 meter long, spaced 1,5-2 meter in crown and bench with wiremesh in crown then shotcrete: 50-100 mm in crown, and 30 mm in sides, without steel ribs support.

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Characterization of Pare Rock Mass and Support System Design for Head Race Tunnel

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.f9575.038620 ◽

2020 ◽

Vol 8 (6) ◽

pp. 5546-5552

Keyword(s):

Rock Mass ◽

Support System ◽

Critical Examination ◽

Hydroelectric Power ◽

Bedding Planes ◽

Rock Mass Quality ◽

Rock Structure ◽

General Response ◽

Power Project

The Head Race Tunnel (HRT) of Pare Hydro-Electric Power Project in Arunachal Pradesh, India, traverses through the Upper-Siwalik Sub-Group of the Sub-Himalayan Range, exhibiting spatial heterogeneity with respect to geotechnical and geological properties. In such complex geological set up, consisting of bedding planes, joints, fractures,varied hydrological conditions etc., prediction of rock mass quality or the characterization of the rock massis a difficult task. Although challenging, it is important to predict the general response of the rock massto tunnel excavation. This paper attempts to characterize Pare Rock Mass around the HRT, based on Rock Quality Designation (RQD), Terzaghi’s Rock Load Theory, Rock Structure Rating (RSR), Rock Mass Rating (RMR), and, Rock Mass Quality (Q) system. An attempt is also made to design the support system for HRT through Pare Rock Mass, based on these parameters. A critical examination of various support systems derived from the above mentioned methods and the support system actually provided at the HRT at Pare Hydroelectric Power Project is also presented in the paper. The study presented in this paper will providean insight about the suitability of a particular method in the design of support system in a rock mass similar to Pare rock mass.

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Guidelines for selecting ground support system for the Talnakh operations based on the rock mass quality assessment

Gornyi Zhurnal ◽

10.17580/gzh.2018.10.18 ◽

2018 ◽

pp. 101-106

Author(s):

V. A. Eremenko ◽

◽

I. I. Ainbinder ◽

V. P. Marysyuk ◽

Yu. N. Nagovitsyn ◽

...

Keyword(s):

Rock Mass ◽

Quality Assessment ◽

Support System ◽

Ground Support ◽

Rock Mass Quality

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Analysis of Support Systems and Excavation Methods Based on Rock Mass Quality in the Intake Tunnel of the Jlantah Dam

E3S Web of Conferences ◽

10.1051/e3sconf/202132502009 ◽

2021 ◽

Vol 325 ◽

pp. 02009

Author(s):

Doni Apriadi Putera ◽

Heru Hendrayana ◽

Hendy Setiawan

Keyword(s):

Rock Mass ◽

Support System ◽

Support Systems ◽

Geological Mapping ◽

Tunnel Support ◽

Rock Mass Quality ◽

System Method ◽

Geological Conditions ◽

Q System ◽

Excavation Methods

Research on the classification of rock mass quality in the intake tunnel Jlantah dam has not been carried out in detail because the research focuses on the location of the main dam so that empirical excavation methods and support systems have not been carried out. The rock mass quality will be used as a parameter in determining the excavation method and tunnel support system that will be used in the Jlantah Dam intake tunnel. The investigation was carried out through engineering geological mapping, core drill evaluation, and supported by laboratory test data based on the Rock Mass Rating (RMR) and Q-system rock mass classification. The rock mass at the research location based on the RMR classification is in class IV (poor rock). Based on the Q-system method, a very poor rock class is obtained. Based on the analysis of the RMR and Q-system methods, the suitable support system for engineering geological conditions such as the intake tunnel of the Jlantah Dam is shotcrete 10 cm thick, steel set with a distance of 1.5 m and rockbolt length of 1.6 m with a distance of 1.5 m. The proper excavation method for the tunnel intake is top heading and bench.

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Modified RMR to determine rock mass quality, study case of diversion tunnel in Meninting Dam, West Nusa Tenggara, Indonesia

E3S Web of Conferences ◽

10.1051/e3sconf/202132502001 ◽

2021 ◽

Vol 325 ◽

pp. 02001

Author(s):

Brilyan Jati Wijaya ◽

I Wayan Warmada ◽

I Gde Budi Indrawan

Keyword(s):

Rock Mass ◽

Rock Surface ◽

Diversion Tunnel ◽

Planning Stage ◽

Rock Mass Quality ◽

Accuracy And Precision ◽

Mass Classification ◽

Study Case ◽

Under Construction ◽

Discontinuity Conditions

The Meninting Dam under construction on Lombok Island, West Nusa Tenggara, Indonesia, requires a good planning to build a diversion tunnel to support its development and mobilization. The diversion tunnel is planned to be built through rocks with medium to poor rock mass quality. The planning stage involves various parameters, i.e., the rock mass classification, using either the RMR or GSI method. Converting values from one method to another makes planning work easier. However, the constraints found were the limitations of the observational data, such as discontinuity conditions. The objective of this article is to discuss the alternative depiction of discontinuity conditions in rock mass using RMR method. An alternative equation was developed to obtain a prediction model for determining the RMR value, based on GSI data. The evaluation showed that the mathematical models developed in this research had a small gap of error compared to other values. The models then can be used to predict RMR value based on GSI data and vice versa, with a higher degree of accuracy and precision according to the actual rock surface conditions, especially in the construction site of diversion tunnel at Meninting Dam.

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

MINING INFORMATIONAL AND ANALYTICAL BULLETIN ◽

10.25018/0236-1493-2019-8-29-3-17 ◽

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

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

Applied Sciences ◽

10.3390/app9102065 ◽

2019 ◽

Vol 9 (10) ◽

pp. 2065 ◽

Cited By ~ 3

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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