To case traffic congestion Seoul Metropolitan Government formulated the 2nd Phase of Seoul Subway Construction Project in 1989. The project called for the construction of 160km of subway which included addition of 4 more subway lines and extension of 3 existing subway lines in addition to the existing 118km of subway. As a final stage of the project subway line 6 is under construction. The line 6 is 36.1 km-Iong route. The line was opened by the end of 2000. With the completion of the line Seoul \~II.1have 278km of subway network and the transport shared by subway will be increased from 25% in 1992 to 50% in 2002. In addition to Seoul subway project, the cases of underground space utilization such as energy storage, food storage, high-speed railway and underground car parking area arc also described in this paper. In Korea many large-scale structures have been constructed since1970s. This paper is a brief description of the current large- scale underground projects in Korea. some of which have been completed already.
Subway Construction Project except for the depot main line arc underground and major construction methods were cutand cover and tunnelling, As a tunnelling method New Austrian Tunnelling Method (NATM) was adapted. the line was opened In the end of 2000. With the completion of the line Seoul has 2~8~111 of subway network and the transport shared by subway w,\Ilncrease from 25% in 1992 to 50% in 2002. therefore, was weathered rocks or weathered soils. Substantiallengths of tunnels are being constructed and designed running through the alluvial deposits as well. In Korea many large-scale Structures have been constructed since 1970s, Technical experiencesaccumulated in the areas of underground rock engineering have. made it possible 10 undertake large-scale projects with do- ~estlc technology, This is a brief representation of large tunnellingand underground storage projects in Korea. some of whicharc still in progress.
According 10 Korea's stockpiling program, the construction of oil storage facilities began in the late 1970s and the first large ~nderground caverns for storing crude oil were built in 1985. hree additional facilities for underground LPG storage con-:~1Ibuted to ~ccomplishing the goal of st?ckpiling of crude oil for e 60-day s consumption III 1988 1he rapid Increase m oi! cOI~s.lIl11ption, however, required more construction of storage facilities, in order to maintain the stockpiling amount correspo. nding to the 60-day's consumption. Fable I lists the storage cavern in operation or under constr~ c~ion in Korea. K-I. U-2 and L-I have the extensions of preeXlstlllg facilities. AS shown in Table I. the first underground ~torage facility, which can store 231.000kl of refined oil. was 1I11~ In a granitic rock mass in the vicinity of caul. The crosssectIonal dimension is 15m × 20m with the total length of 1,262m. The construction was started in 1975 and was completed III 1982.
