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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Tunnel and Underground Space
Journal Basic Information
Journal DOI :
Korean Society for Rock Mechanics
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Volume & Issues
Volume 25, Issue 6 - Dec 2015
Volume 25, Issue 5 - Oct 2015
Volume 25, Issue 4 - Aug 2015
Volume 25, Issue 3 - Jun 2015
Volume 25, Issue 2 - Apr 2015
Volume 25, Issue 1 - Feb 2015
Selecting the target year
Study on Effectiveness of Selection for Railway Ballast : Case Study on A Quarry in northen France
Woo, Ik ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 487~495
DOI : 10.7474/TUS.2015.25.6.487
The specification for selecting railway ballast in France is introduced in this study and the effectiveness of selection for railway ballast is studied for the case of a quarry located in northen France. The quality of railway ballast is, in general, estimated depending on the grain distribution and mainly of the resistance against abrasion. The resistance against abrasion is obtained by both Los Angeles abrasion test and Micro Deval test, which determine the ballast quality suitable whether for high speed railway or classical railway. This study analyzed the correlation between the abrasion index obtained from the abrasion tests for the aggregates sampled at three different stages among ballast production procedure at the quarry. A high correlation is determined between Los Angeles Abrasion index (LA) and Micro Deval index (MDA) and also between abrasion indices of different aggregates. Particularly, this correlation between the abrasion indices allows to estimate the quality of ballast at the final stage from the aggregates at the site in a quarry within the margin of error.
Performance Evaluation of Conical Picks for Roadheader in Copper Mines
Choi, Soon-Wook ; Chang, Soo-Ho ; Lee, Chulho ; Lee, Gyu-Phil ; Bae, Young Hwan ; Ha, Tae-Wook ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 496~504
DOI : 10.7474/TUS.2015.25.6.496
Roadheader that excavates ground using pick cutters installed on the cutting head is one of the partial-face machines. A conical cutter among pick cutters is excavation tool decreasing the loss of cutter using tungsten carbide insert at the tip of the cutter and it has been widely used in the roadheaders. In this study, durability performance for three kinds of conical cutters was evaluated in copper mines composed of Manto and conglomerate. After field test, the visual inspection as well as the weight loss measurement of pick cutters was carried out to investigate the damage of pick cutters. In addition, CT scan and SEM were performed to check whether or not crack and apertures in pick cutters. As results, the conical cutter with hardfacing was evaluated as having the best durability performance and it was unable to find cracks in all cutters investigated.
Comparison the Effect of In-situ Mixing Method and Mixed Laying Method for Construction of Stabilizing Layer on Heavy Metal Contaminated Soil
Lee, Sang-Moo ; Kim, Jin-Hwan ; Yun, Yeo-Joon ; Kim, Yoon-Su ; Park, Nam-Seo ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 505~514
DOI : 10.7474/TUS.2015.25.6.505
In this study, a stabilizing equipment was developed to resolve the problems of existing stabilization construction method for contaminated soil. The field application and workability of the stabilizing equipment were verified through field demonstration tests and laboratory tests. The field application of the stabilizing equipment was identified through field demonstration tests. As a result of laboratory tests for field mixed soil, the mixing capability of stabilizer of the developed construction method was better than that of existing construction method.
Study on the Convergence of the NATM Tunnel Constructed in the Weathered Granite
Shin, Sang-Sik ; Kim, Hak Joon ; Bae, Gyu Jin ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 515~526
DOI : 10.7474/TUS.2015.25.6.515
Predicting and measuring tunnel convergence is very crucial for estimating tunnel stability and economical construction of NATM tunnels. The method to estimate the tunnel convergence that occurs before and after construction is proposed based on literature reviews. The total displacement occurring related to tunnel construction is determined to be about 2.5 times that of measured displacements. The results of displacement measurements at two tunnels constructed with similar rock types are examined for the investigation of factors affecting the tunnel convergence. The average convergence of Gyungju A Tunnel is about 6.7 times bigger than that of Daejeon B Tunnel. The possible causes of the large convergence in Gyungju A Tunnel are suggested. In order to predict the convergence of tunnels, careful investigation of the geological structures in the ground surface and the influence of external conditions as well as careful face mapping of the tunnel face should be conducted.
On-site Demonstration of Topographic Surveying Techniques at Open-pit Mines using a Fixed-wing Unmanned Aerial Vehicle (Drone)
Lee, Sungjae ; Choi, Yosoon ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 527~533
DOI : 10.7474/TUS.2015.25.6.527
This study performed an on-site demonstration of the topographic surveying technique at a large-scale open-pit limestone mine in Korea using a fixed-wing unmanned aerial vehicle (UAV, Drone, SenseFly eBee). 288 sheets of aerial photos were taken by an automatic flight for 30 minutes under conditions of 300 m altitude and 12 m/s speed. Except for 37 aerial photos in which no keypoint was detected, 251 aerial photos were utilized for data processing including correction and matching, then an orthomosaic image and digital surface model with 7 cm grid spacing could be generated. A comparison of the X, Y, Z-coordinates of 4 ground control points measured by differential global positioning system and those determined by fixed-wing UAV photogrammetry revealed that the root mean squared errors were around 15 cm. Because the fixed-wing UAV has relatively longer flight time and larger coverage area than rotary-wing UAVs, it can be effectively utilized in large-scale open-pit mines as a topographic surveying tool.
Development of an Optimized Prediction System of Round Trip Occurrence using Genetic Algorithm
Lee, Seung Soo ; Seo, Jong Won ; Kim, Kwang Yeom ; Shin, Hyu-Soung ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 534~542
DOI : 10.7474/TUS.2015.25.6.534
Round trip activity occurs discretely due to the abrasion of drill bit in the deep drilling project. Round trip has great impact on the drilling performance because it takes more time to change a drill bit as the depth goes deeper. Therefore, a reliable prediction technology of the round trip should be secured for feasibility analysis and effective management of the drilling project. Lee et al. (2013) developed the TOSA (round trip occurrence simulation algorithm) which can analyze the depth and timing of round trip occurrence at each abrasion state of bit. However, TOSA has weakness that it takes long time for simulation because the number of simulation increase exponentially as increasing the number of simulation section. This study developed the TOSA based round trip performance prediction module using genetic algorithm for simulating in a short time and verified simulation results.
Development of a Low Pressure Auxiliary Fan for Local Large-opening Limestone Mines
Lee, Chang Woo ; Nguyen, Van Duc ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 543~555
DOI : 10.7474/TUS.2015.25.6.543
At present, local limestone mines with large opening employ auxiliary fans for workplace ventilation which have been used in coal mines with much smaller airways. Considering the low static pressure loss in the large-opening mines, high pressure auxiliary fans face serious economical limitations mainly due to their excessive capacity. The optimal fan selected for the ventilation in large-opening working places should supply air quantity enough for maintaining safe environment and keep its operating cost as low as possible. This study focuses on the development of a low pressure auxiliary fan designed to have smaller range of the static head but to have more potential for higher ventilation and energy efficiency. The flow characteristics of high and low pressure auxiliary fans were theoretical as well as experimentally investigated to assess the ventilation efficiency in term of environmental and economical aspects. Moreover, the low pressure fan was tested in two limestone mine sites with small and large cross-sectional areas for evaluating its ventilation efficiency. Results from this study can be applied to improve the economy and efficiency of auxiliary fan for ensuring better air quality and work environment management.
THM Coupling Analysis for Decovalex-2015 Task B2
Kwon, Sangki ; Lee, Changsoo ; Park, Seung-Hun ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 556~567
DOI : 10.7474/TUS.2015.25.6.556
The evaluation of THM coupling behavior in deep underground repository condition is essential for the long term safety and stability assessment of high-level radioactive waste repository. In order to develop reliable THM analysis techniques effectively, an international cooperation project, DECOVALEX, is carried out. In DECOVALEX-2015 Task B2, the in situ THM experiment planned to be conducted by JAEA was modeled by the research teams from the participating countries. In this study, a THM coupling technique combining TOUGH2 and FLAC was developed and applied to 1 dimensional THM modeling, in which rock, buffer, and heater are considered. The results were compared with those from other research teams.
Analyses of Scenarios Based on a Leakage of Highly Compressed Air and Fire Anticipated in CAES (Compressed Air Energy Storage) Facility
Yoon, Yong-Kyun ; Ju, Eun-Hye ;
Tunnel and Underground Space, volume 25, issue 6, 2015, Pages 568~576
DOI : 10.7474/TUS.2015.25.6.568
In this study, scenarios based on the leakage of highly compressed air and fire occurrence turned out to be high risks in an operation stage of CAES facility were constructed and estimated. By combining Bernoulli equation with momentum equation, an expression to calculate an impact force of a jet flow of compressed air was derived. An impact force was found to be proportional to the square of diameter of fracture and the pressure of compressed air. Four types of fire scenarios were composed to evaluate an effects that seasonal change and location of fire source have on the spread behavior of smoke. Smoke from the fire ignited in the vicinity of CAES opening descended more quickly below the limit line of breathing than one from the fire occurred 10 m away from CAES opening, which is expected to occur due to a propagation of wave front of smoke. It was shown that a rate of smoke spread of the winter fire is faster than one of the summer fire and smoke from the winter fire spreads farther than one of the summer fire, which are dependent on the direction of air flow into access opening. Evacuation simulation indicated that the required safe evacuation time(RSET) of the summer and winter fires are 262, 670 s each.