scholarly journals A Study of the Effects of Geological Conditions on Korean Tunnel Construction Time Using the Updated NTNU Drill and Blast Prediction Model

2021 ◽  
Vol 11 (21) ◽  
pp. 10096
Author(s):  
Yangkyun Kim ◽  
Sean Seungwon Lee
Keyword(s):  
Rock Mass ◽  
Prediction Model ◽  
Rock Properties ◽  
Design Stage ◽  
Construction Time ◽  
Tunnel Support ◽  
Advance Rate ◽  
Rock Mass Quality ◽  
Geological Conditions ◽  
Drill And Blast

This paper analyses the construction time and advance rate of a 3 km long drill and blast tunnel under various geological conditions using an upgraded NTNU drill and blast prediction model. The analysis was carried out for the five types of Korean tunnel supports according to the rock mass quality (from Type 1, meaning a very good rock mass quality; to Type 5, meaning a very poor rock mass quality). Four kinds of rock properties, as well as the rock mass quality, for each tunnel support type were applied to simulate different geological conditions based on previous studies and the NTNU model. The construction time was classified into five categories: basic, standard, gross, tunnel and total, according to the operation characteristics to more effectively analyse the time. In addition, to consider the actual geological conditions in tunnelling, the construction times for the three mixed geological cases were analysed. It was found that total construction time of a tunnel covering all the operations and site preparations with a very poor rock mass quality was more than twice that of a tunnel with a very good rock mass quality for the same tunnel length. It is thought that this study can be a useful approach to estimating the construction time and advance rate in the planning or design stage of a drill and blast tunnel.

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

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.

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 Tunnel support design by comparison of empirical and finite element analysis of the Nahakki tunnel in mohmand agency, pakistan

2016 ◽  
Vol 38 (1) ◽  
pp. 75-84
Author(s):  
Asif Riaz ◽  
Syed Muhammad Jamil ◽  
Muhammad Asif ◽  
Kamran Akhtar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rock Mass ◽  
Support Systems ◽  
Classification Systems ◽  
Geological Strength Index ◽  
Support Design ◽  
Element Analysis ◽  
Tunnel Support ◽  
Geological Conditions

Abstract The paper analyses the geological conditions of study area, rock mass strength parameters with suitable support structure propositions for the under construction Nahakki tunnel in Mohmand Agency. Geology of study area varies from mica schist to graphitic marble/phyllite to schist. The tunnel ground is classified and divided by the empisical classification systems like Rock mass rating (RMR), Q system (Q), and Geological strength index (GSI). Tunnel support measures are selected based on RMR and Q classification systems. Computer based finite element analysis (FEM) has given yet another dimension to design approach. FEM software Phase2 version 7.017 is used to calculate and compare deformations and stress concentrations around the tunnel, analyze interaction of support systems with excavated rock masses and verify and check the validity of empirically determined excavation and support systems.

scholarly journals Evaluation on the TBM Performance at a Hydropower Project in Ecuador

2019 ◽  
Vol 24 ◽  
pp. 10-16
Author(s):  
Krishna Kanta Panthi ◽  
Jhonny Encalada
Keyword(s):  
Rock Mass ◽  
San Francisco ◽  
Penetration Rate ◽  
Tunnel Boring Machine ◽  
Quality Parameters ◽  
Hydropower Project ◽  
Tbm Performance ◽  
Rock Mass Quality ◽  
Geological Conditions ◽  
Headrace Tunnel

The aim of this manuscript is to discuss the Tunnel Boring Machine (TBM) performance along the recently constructed headrace tunnel of Minas-San Francisco Hydropower Project in Ecuador. Firstly, the manuscript briefly describes the importance of TBM tunneling and about the Minas-San HPP. Further, discussions are made on the engineering geological conditions along the headrace tunnel. Detailed evaluations are made on the performance of TBM tunneling considering influence of rock mass quality on the TBM penetration rate. The manuscript emphasizes that the knowledge of the rock mass quality parameters and cutter technology available at present are among the key factors that influence the estimation of the net penetration rate of the TBM. It has been demonstrated that the hard to very hard rock masses of high abrasivity that were encountered along the headrace tunnel alignment caused very low penetration giving slow progress, which was not predicted during planning phase design. The authors investigated a fairly good link between TBM penetration and the mechanical strength of the rock mass.

scholarly journals Engineering geological mapping for empirical design evaluation of Tunnel 10 of Jakarta - Bandung high-speed railway, Indonesia

2021 ◽  
Vol 325 ◽  
pp. 01006
Author(s):  
Hanifah Hilda Herdiana ◽  
I Gde Budi Indrawan ◽  
Hendy Setiawan
Keyword(s):  
Rock Mass ◽  
Support System ◽  
High Speed ◽  
Geological Mapping ◽  
Construction Site ◽  
Engineering Geological Mapping ◽  
High Speed Railway ◽  
Tunnel Support ◽  
Geological Conditions ◽  
Empirical Design

An engineering geological mapping was carried out at the construction site of the Tunnel 10 of Jakarta Bandung High-Speed Railway to obtain data and information of the engineering geological conditions, particularly the rock masses. This research aims to determine the rock mass classes at the tunnel construction site and recommend the tunnel support system based on the Rock Mass Rating (RMR) and the Japan Society of Civil Engineers (JSCE) systems. This research is expected to better understand the rock mass classes, which were previously determined based on the newly applied Basic Quality (BQ) system for the tunnel support empirical design. The results showed that the research area consisted of young volcanic products, namely moderate to highly weathered tuff breccia and andesitic breccia. The uniaxial Compressive Strength (UCS) of rock mass varies between 1-25 MPa. The RMR value ranges from 21 to 40, indicating disintegrated and poor rock mass quality. The proposed tunnel support system is the combination of shotcrete, steel support for top heading and bench support, arch sidewall, and invert concrete.

Efficient PDC Bit Designs Reduced Vibrational Impact While Drilling with Rotary Steerable Systems in the Geological Conditions of the Yamalo-Nenets Autonomous District

2021 ◽  
Author(s):  
Andrey Vyacheslavovich Garipov ◽  
Andrey Aleksandrovich Rebrikov ◽  
Aydar Ramilevich Galimkhanov ◽  
Andrey Valerievich Mikhaylov ◽  
Almaz Sadrikhanovich Khalilov ◽  
...  
Keyword(s):  
Drill Pipe ◽  
Polycrystalline Diamond ◽  
Rock Properties ◽  
Construction Time ◽  
Test Beam ◽  
Specialized Software ◽  
Drilling Performance ◽  
Geological Conditions ◽  
Vibration Impact ◽  
Nenets Autonomous

Abstract This article is a description of a comprehensive engineering approach to new designs of PDC (Polycrystalline Diamond Compact) Bits and bottomhole equipment for efficient horizontal wells drilling in the Yamal-Nenets Autonomous Okrug (YNAO) fields with Rotary Steerable Systems (RSS) Point the Bit (PTB) type. The paper represents an analysis of the efficiency of drilling rocks of various hardness depending on the bits, the bottom hole assembly (BHA), and type of vibrations. In the Yamal region fields a main constraint of sub horizontal sections drilling performance for liner run in hole is the occurrence of vibrations. The predominant vibration types are Stick and Slip (S&S) and High Frequency Torsional Oscillations (HFTO). These types of vibrations often had to be reduced by limiting drilling regime (weight on bit (WOB), drill pipe (DP) RPM, and flow rate), which directly affected on the rate of penetration (ROP). To find solutions to this problem for drilling performance improvement, geological and geomechanically modeling of rock properties and an analysis of burst-files of vibrations (modeled in specialized software) were carried out based on downhole data. The studies have found key factors that cause the high vibration impact and reasons for premature wear of the PDC bits, which served as a basis for identifying the shortcomings of previous bit designs. Test beam experiments were also performed to assess the bits wear while drill-out of the casing accessories. The results formed the basis for development of new PDC bits designs using specialized software. As an output new 155.6/152.4 mm bits designs with an innovative cutting structure that considers the geological features and technical aspects of drilling liner sections in YNAO fields were manufactured. The new bit designs have significantly reduced vibration levels, improved ROP performance in the liner section using RSS PTB, and decreased the overall well construction time. These solutions open wide opportunities for their further implementation on other projects both in Russia and in other CIS countries.

scholarly journals Role of Geologists During Tunnel Construction and Face Mapping to Decide the Required Tunnel Support

2021 ◽  
Vol 9 (9) ◽  
pp. 2080-2081
Author(s):  
Deepak Parkash Gupta
Keyword(s):  
Failure Modes ◽  
Design Stage ◽  
Underground Structures ◽  
Tunnel Support ◽  
Execution Phase ◽  
Geological Conditions ◽  
Ground Conditions ◽  
The Stability ◽  
Stress Behaviour

Abstract: The stability of underground structures is an important aspect during design, construction and execution Phase. Depending on the geotechnical conditions and influencing factors, different failure modes during execution mode can be expected, and depending on the potential failure modes, boundary conditions and specific construction measures to ensure stability have to be chosen. The most important is developing a realistic estimate of the expected ground conditions and their potential behaviour/failure modes as a result of the excavation. The variability of the geological conditions including local ground structure, ground parameters, stress and ground water conditions requires that a consistent and specific procedure is used. The other is to design an economic and safe excavation and support method for the determined ground behaviours. The discussion of role of geologists during design stage is beyond the scope of the present study. The main objective of this study is to present the role of geologists during the construction stage. Keywords: Geologist, Stress, Behaviour, RMR, Q Value, RQD, Rock Mass

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

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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