• Tunnel and Underground Space
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• v.22 no.5
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• pp.297-309
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• 2012

The stability assessment of abandoned gangway for the purpose of services was performed. Among the many factors that affect the stability of openings, the span of the opening in a given rock mass condition provides an important element of design. In this paper, the stability of gangway was assessed by the critical span curves proposed by Lang, the modified Mathews'stability graph method and using support measures of the Q system. In the evaluation of stability as a whole the gangway is considered as stable. But the rockfalls of wedge-shaped blocks were expected in the area in which the horizontal joints of low angle appear. The support measures such as local rock bolts are required to use for commercial purposes of the abandoned gangway. And entrance section may require the particular attention as unstable section. Since there are so many spalling due to bad blasting in the roof and sidewall of gangway, the scaling operations should be followed primarily.

• Tunnel and Underground Space
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• v.17 no.5
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• pp.372-380
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• 2007

Surface damage due to subsidence is an inevitable consequence of underground mining, which may be immediate or delayed for many years. The surface damage due to abandoned underground mine is observed to be two subsidence types such as simple sinkhole or trough formation to a large scale sliding of the ground from with in the subsided area. An evaluation of the risk of a subsidence occurrence is vital in the areas affected by mining subsidence. For a subsidence prediction or a risk evaluation, there has been used various methods using empirical models, profile functions, influence functions and numerical models. In this study, a simple but efficient evaluation method of subsidence hazard is suggested, which is based on a diffusion theory and uses just information about geometry of caving and topography. The diffusion model has an analogous relationship with granular model which can explain a mechanism of subsidence. The diffusion model is applied for the evaluation of subsidence hazard in abandoned metal and coal mines. The model is found to be a simple but efficient tool because it needs information of geometry of caving and gangway and the topography.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.327-336
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• 2013

Approximately 70% of the Korean peninsula is composed of mountains, around 99,274 $km^2$. Even worse, population rate of Korea is the No.3 in the world now. Accordingly, it is necessary to develop the potential underground space actively with the concept of another territory to be utilized. The development of underground space should be considered not a choice but an indispensable issue. Since 1970s, many large-scale underground structures have been constructed like as crude-oil storage bins, liquefied petroleum gas storage caverns, and underground pumped storage powerplants. Also, In urban area, the underground facilities such as subway networks, underground shopping mall, underground pedestrian network, electric power tunnels, and car parking lots have been used extensively. The scale of Yeosu oil and gas underground storage facility and Seoul subway systems are one of the massive scale in the world. Recently, the trend of the development of underground space becomes more diverse and larger scale. The current status of Korean underground space developments and strategy are described in this paper.