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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
Editor in Chief :
Volume & Issues
Volume 23, Issue 6 - Dec 2013
Volume 23, Issue 5 - Oct 2013
Volume 23, Issue 4 - Aug 2013
Volume 23, Issue 3 - Jun 2013
Volume 23, Issue 2 - Apr 2013
Volume 23, Issue 1 - Feb 2013
Selecting the target year
A Case Study of Tunnel Stability due to the Shallow Shaft and Change Penetrating Location
Lee, Saik ; Choi, Youngchul ; Jung, Wooyong ; Kim, Kookhan ; Kim, Dongin ;
Tunnel and Underground Space, volume 23, issue 2, 2013, Pages 87~98
DOI : 10.7474/TUS.2013.23.2.087
Around 70% of Korea is mountainous, an increase in tunnel construction. It's due to the growing interest of the public for the environment and land required for the road construction is very scarce. During construction of 'Daedong 1 tunnel' in the expressway expansion project between Naengjeong and Busan, there are shallow shaft due to this tunnel located in the valley and the shafts are separated, and penetrating location change was inevitable for construction was delayed because of complaint. So, we change the position of the penetrating by applying multi-channel TSP, and conducted a stability analysis. The analysis results showed that there is no problem on the stability of the tunnel. To secure the construction of additional stability, We installed instrument, performed mechanical excavation, added reinforcement at shallow shaft and conducted bench cut.
Stability Assessment on the Final Pit Slope in S Limestone Mine
Sun, Woo-Choon ; Lee, Yun-Su ; Kim, Hyun-Woo ; Lee, Byung-Joo ;
Tunnel and Underground Space, volume 23, issue 2, 2013, Pages 99~109
DOI : 10.7474/TUS.2013.23.2.099
The slopes of open-pit mine are typically designed without considering the reinforcement and support method due to the economical efficiency. However, the long-term stability of final pit slope is needed in some case, therefore the appropriate measures that can improve the stability are required. In this study, the field survey and laboratory test were carried out in S limestone mine. The stability assessment of final pit slope was performed through the stereographic projection method, SMR, and numerical analysis. And countermeasures for stabilization were proposed. The results of analysis show that full scale of slope failure is not expected but the failures of bench slope scale are likely to occur. In oder to increase the stability of bench slope, we suggested the remedial methods as follows: excavating the final pit slope by pre-splitting blasting, placing the wide berm in the intermediate bench slope and installing the horizontal drainage hole in the place of local ground water runoff.
Relations between Initial Displacement Rate and Final Displacement of Arch Settlement and Convergence of a Shallow Tunnel
Kim, Cheehwan ;
Tunnel and Underground Space, volume 23, issue 2, 2013, Pages 110~119
DOI : 10.7474/TUS.2013.23.2.110
It is generalized to measure the arch settlement and convergence during tunnel construction for monitoring its mechanical stability. The initial convergence rate a day is defined from the first convergence measurement and the final convergence defined as the convergence measured lastly. The initial and the final tunnel arch settlement are defined like the preceding convergence. In the study, the relations between the initial and final displacements of a shallow tunnel are analyzed. The measurements were performed in the tunnel of subway 906 construction site in Seoul. The overburden is 10-20 m and the tunnel goes through weathered soil/rock. The width and height of the tunnel are about 11.5 m, 10m, respectively. So this is a shallow tunnel in weak rock. The length of tunnel is about 1,820 m and the tunnel was constructed in 2 stages, dividing upper and lower half. The numbers of measurement locations of arch settlement and convergence are 184 and 258, respectively. As a result, the initial displacement rate and the final displacement are comparatively larger in the section of weathered soil.
Measurement of Tunnel Arch Settlements Ahead of and Behind the Tunnel Face Using a Horizontal Inclinometer and Settlement Pins
Kim, Cheehwan ;
Tunnel and Underground Space, volume 23, issue 2, 2013, Pages 120~129
DOI : 10.7474/TUS.2013.23.2.120
It is important to measure the displacement behind and ahead of a tunnel face during construction for evaluating mechanical stability by comparing it to a displacement criteria set by tunnel designers. The 30 m long horizontal inclinometer was installed frontward from the tunnel face and the displacement occurred ahead of a tunnel face during excavation was measured by using it. Tunnel arch settlements behind tunnel face were surveyed using a settlement pins on the arch. So total settlement and longitudinal displacement curve were obtained combining settlement measured by both the horizontal inclinometer ahead of tunnel face and the settlement pins behind the tunnel face.
Scale Model Studies for Stability Estimation of Twin Tunnels with Small Clearance
Kim, Pyoung Gi ; Kim, Jong Woo ;
Tunnel and Underground Space, volume 23, issue 2, 2013, Pages 130~140
DOI : 10.7474/TUS.2013.23.2.130
In this study, scaled model tests were performed to investigate the stability of twin tunnels with small clearance, where the pillar widths were 0.5D and 0.25D, respectively. The tunnels were supposed to be constructed in anisotropic weathered rocks with
inclined bedding planes, and the model tests were conducted under the condition of lateral pressure ratio, 1. Six types of test models which had respectively different pillar widths and support conditions were experimented, where crack initiating pressures, maximum pressures, failure modes of pillar and deformation behaviors around tunnels were investigated. The models with wider pillar were cracked under higher pressure than the models with shallower pillar. The models with lining support were cracked under higher pressure and showed less tunnel convergence than the unsupported models. The models with both lining and pillar reinforcement were proved to be most stable among the tested models. In particular, as the model of 0.25D pillar width with only lining support showed shear failure of pillar according to the existing bedding planes, so both lining and pillar reinforcement were thought to be indispensable in that case of tunnel.
Thermal Analysis of a Horizontal Disposal System for High-level Radioactive Waste
Choi, Heui-Joo ; Kim, In-Young ; Lee, Jong Youl ; Kim, Hyun Ah ;
Tunnel and Underground Space, volume 23, issue 2, 2013, Pages 141~149
DOI : 10.7474/TUS.2013.23.2.141
The thermal analysis is carried out for a geological disposal system developed for the final disposal of a ceramic high-level waste from pyroprocessing of PWR spent fuel. The horizontal disposal tunnel type is considered with the distance of 2 m between the disposal canisters and the tunnel spacing of 25 m. The temperature distributions around the disposal canisters are calculated for the horizontal tunnel based on the conceptual design. The thermal performance analysis is carried out using a FEM program, ABAQUS. The performance analysis shows that the peak temperature in a disposal system outside the disposal canister is lower than
, which meets the thermal criterion of the disposal system. According the analysis, the peak temperature for the disposal canister located boundary of the disposal system is lower by
than that for the canister at the central area. This implies the disposal density can be improved by locating more disposal canisters along the boundary.
Mechanical Stability Analysis to Determine the Optimum Aspect Ratio of Rock Caverns for Thermal Energy Storage
Park, Dohyun ; Ryu, Dongwoo ; Choi, Byung-Hee ; Sunwoo, Choon ; Han, Kong-Chang ;
Tunnel and Underground Space, volume 23, issue 2, 2013, Pages 150~159
DOI : 10.7474/TUS.2013.23.2.150
It is generally well known that the stratification of thermal energy in heat stores can be improved by increasing the aspect ratio (the height-to-width ratio) of the stores. Accordingly, it will be desirable to apply a high aspect ratio so as to demonstrate the good thermal performance of heat stores. However, as the aspect ratio of a store increases, the height of the store become larger compared to its width, which may be unfavorable for the structural stability of the store. Therefore, to determine an optimum aspect ratio of heat stores, a quantitative mechanical stability assessment should be performed in addition to thermal performance evaluations. In the present study, we numerically investigated the mechanical stability of silo-shaped rock caverns for underground thermal energy storage at different aspect ratios. The applied aspect ratios ranged from 1 to 6 and the mechanical stability was examined based on factor of safety using a shear strength reduction method. The results from the present study showed that the factor of safety of rock caverns tended to decrease with the increase in aspect ratio and the stress ratio of the surrounding rock mass was influential to the stability of the caverns. In addition, the numerical results demonstrated that under the same conditions of rock mass properties and aspect ratio, mechanical stability could be improved by the reduction in cavern size (storage volume), which indicates that one can design high-aspect-ratio rock caverns by dividing a single large cavern into multiple small caverns.