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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Korean Tunnelling and Underground Space Association
Journal Basic Information
Journal DOI :
Korean Tunnelling and Underground Space Association (KTA)
Editor in Chief :
Volume & Issues
Volume 15, Issue 6 - Nov 2013
Volume 15, Issue 5 - Sep 2013
Volume 15, Issue 4 - Jul 2013
Volume 15, Issue 3 - May 2013
Volume 15, Issue 2 - Mar 2013
Volume 15, Issue 1 - Jan 2013
Selecting the target year
Mode II fracture toughness determination of rocks using short beam compression test
Ko, Tae Young ; Kemeny, J. ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 547~557
DOI : 10.9711/KTAJ.2013.15.6.547
The mode II fracture toughness and strength due to shear stress are important parameters in the stability of caprock and injection zone with application to geological sequestration of carbon dioxide. In this research, a short beam compression test has been used to determine the shear strength and the mode II fracture toughness for Coconino sandstone. The average value of the shear strength and mode II fracture toughness are estimated to be 23.53 MPa and 1.58 MPa
m respectively. The stress intensity factor is suggested by finite element analysis using the displacement extrapolation method. The effect of biaxial stress and water saturation on the fracture toughness has also been investigated. The fracture toughness increases with confining stresses, but decreases by 11.4% in fully saturated condition.
A numerical study on the pressure relief by a vertical shaft in a high speed railway tunnel
Kim, Hyo-Geun ; Seo, Sang-Yeon ; Ha, Hee-Sang ; Kwon, Hyeok-Bin ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 559~570
DOI : 10.9711/KTAJ.2013.15.6.559
High speed railway can transport large quantity of people and commodities in a short time and has become one of the most desirable and environmentally friendly transportation. However, it is hard to have a complicated route for high speed railways, construction of tunnels is essential to pass through a mountain area. When a high speed train enters a tunnel, pressure wave is created in a tunnel and the wave causes micro pressure wave and discomfort to passengers. In order to alleviate pressure wave in a tunnel, constructing a vertical shaft is one of the most efficient ways. This study represents a numerical analysis module, which takes into account the effect of a vertical shaft in a tunnel. The module can be used in a numerical program (TTMA) specialized for aerodynamics in a tunnel, and it was validated by comparing numerical results with various measurements in Emmequerung tunnel and results from numerical analysis using Fluent.
An experimental study on bonding and bearing capacities of thin spray-on liner to evaluate its applicability as a tunnel support member
Han, Jin-Tae ; Lee, Gyu-Phil ; Park, Young-Taek ; Choi, Soon-Wook ; Hwang, Gwi-Sung ; Choi, Myung-Sik ; Chang, Soo-Ho ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 571~583
DOI : 10.9711/KTAJ.2013.15.6.571
The use of Thin Spray-on Liner (TSL) as an alternative to shotcrete has drastically increased since 1990s when it was first developed and introduced to mines. In this study, tensile strength test, bond strength test, compression test with specimens coated by TSL, and two kinds of bending tests proposed by EFNARC (2008) were performed with two kinds of TSLs with different material compositions in order to evaluate their support capacities. As a result, both TSLs were shown to be satisfactory for the minimum performance requirements for a structural rock support suggested by EFNARC (2008) and tensile strength of a TSL was shown to increase as its content of polymer was higher. In contrast, its bond strength was shown to increase proportional to the content of a cementitious component especially at the early age.
A study on conceptual evaluation of structural stability of room-and-pillar underground space
Lee, Chulho ; Chang, Soo-Ho ; Shin, Hyu-Soung ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 585~597
DOI : 10.9711/KTAJ.2013.15.6.585
In this study, in order to evaluate stability of the room-and-pillar underground structure, a series of preliminary numerical analyses were performed. Design concept and procedure of an underground structure for obtaining a space are proposed, which should be different from structural design for the room-and-pillar in mine. With assumed material properties, a series of numerical analyses were performed by varying size ratios of room and pillar and then the failure modes and location at yielding initiation were investigated. From the results, relationship between the ratio of pillar width to the roof span (w/s) and overburden pressure at failure initiation shows a relatively linear relation, and the effect of w/s on structural stability is much more critical than the ratio of pillar width and height (w/H) which is a crucial parameter in design of the room-and-pillar mining. It means that roof tensile failure and shear failure at shoulder and pillar are necessary to be considered together for confirming overall structural stability of the room-and-pillar structure, rather than considering the pillar stability only in mining. Failure modes and location at failure initiation were varied with respect to the ratio of room and pillar widths. Therefore, it is necessary to simultaneously consider stability of both roof span and pillar for design of underground structure by the room-and-pillar method.
A preliminary study on economical efficiency of a room-and-pillar excavation method in comparison with 2-arch tunnelling method
Lee, Chulho ; Chang, Soo-Ho ; Ahn, Sung-Youll ; Shin, Hyu-Soung ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 599~612
DOI : 10.9711/KTAJ.2013.15.6.599
This study aims to investigate an economical efficiency of two excavation methods with respect to the room-and-pillar method for the underground space and conventional excavation method, i.e. 2-arch tunnelling method. For feasibility study, an excavation cost for both room-and-pillar method and 2-arch tunnelling method was estimated when the same space in operation was required. It was assumed that properties of reinforcements and rock were adopted from literatures. However, an excavation shape of the room-and-pillar method was assumed not to be the rectangular shape which is a general type in the room-and-pillar method but to be an arch shape in order to compare with the conventional excavation method (2-arch tunnelling) and to achieve the maximum bearing capacity of the structure during excavation. Consequently, the wider space in use or required and the better condition of rock we assumed, the more economical advantage we have in the room-and-pillar method than the 2-arch tunnelling method.
Business impact analysis for disaster management of large underground limestone mine
Lee, Seong-Min ; Kim, Sun-Myung ; Lee, Yeon-Hee ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 613~623
DOI : 10.9711/KTAJ.2013.15.6.613
As Limestone mines have been operated with various environmental, societal and managemental problems depending on their characteristics and developing methods, many great efforts have been applied to solve these problems. Installing the mining facilities underground is one of the successful efforts to keep the sustainable limestone mine development. This effort could reduce these problems. However, unfortunately it made an side effect of constructing a large underground space in mining site. Moreover, this space caused a necessity of various disaster managements for the safety of workers and facilities. This study introduces the priority list of a limestone mining process if there are disasters in underground mining site. This result is coming from the risk assessment and business impact analysis on survey data which were obtained from the miners of that particular limestone mine. According to the result, the highest risk is `disregard of safety guidelines in crushing & classifier process`. The result also shows the highest priority business, above all things, is `a pit linked work of in & out process`.
Analysis of aerodynamic characteristics for the selection of cross-section to the TBM railway tunnels
Lee, Ho-Keun ; Kang, Hyun-Wook ; Kim, Hyun-Soo ; Kim, Hong-Moon ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 625~635
DOI : 10.9711/KTAJ.2013.15.6.625
Although the TBM method is mainly adopted in overseas market including the Europe, etc, the method scarcely adopted in domestic market. For highly enhancing applications of the TBM method for railway, It is needed to select the optimal cross-section considering design elements of civil engineering and aerodynamic effects. Also, it is needed to establish plan of proper section as well as reviewing aerodynamic effects and consideration about civil engineering elements such as length of tunnel, speed of railway, height of whole lines and size of utility tunnel, etc. Even though it should be recently considered high-speed railway tunnels and required to be standard establishments in aerodynamic reviews, it is being applied to be criteria of inconsistent pneumatic analysis owing to be not related with domestic standards. In this study, therefore, we are willing to establishment of domestic and foreign aerodynamic standards and investigate correlation between optimal cross-section and aerodynamic effects of TBM railway tunnels.
Evaluation of rock load based on critical shear strain concept on tunnels
Kim, Jung-Joo ; Lee, Jae-Kook ; Kim, Jong-Uk ; Yoo, Han-Kyu ;
Journal of Korean Tunnelling and Underground Space Association, volume 15, issue 6, 2013, Pages 637~652
DOI : 10.9711/KTAJ.2013.15.6.637
After studying the characteristics of three different evaluation methods of rock load; namely theoretical method, empirical method and numerical method, there were too many limitations for them to be applied on tunnels. Therefore, in this research paper, the method based on numerical analysis is selected to use as this method is the most reasonable one since it considers all parameters that are necessary for rock load estimations, and it also considers the interaction between ground and tunnel support. The critical shear strain concept formulated by Sakurai (1981) was used in order to measure exact rock load values based on numerical analysis. Evaluation on a Level 1 rock load height, which is depicted by the stable region in the graph shows that rock load is not affecting between ground grade 1~3, and it was evaluated that the fourth and fifth grades show less values of rock load height which led to the conclusion of a more economical design of concrete lining.